Optimize webhooks JSON with compact format and string interning

- Convert params to compact array format (type-based dispatch)
- Intern duplicate property names into string table
- Use negative indices for object references to distinguish from string indices
- Rename objects.json → webhooks.objects.json, add webhooks.strings.json
- Move event filters to JSON for maintainability
- Add CI validation job to verify optimization correctness

Reduces combined minified size by ~67% (453 KB → 148 KB), ~27% gzipped (23 KB → 17 KB).

.github/workflows/buildtest.yml

@@ -12,18 +12,85 @@ jobs:
   build:
     runs-on: ubuntu-latest
 
+    strategy:
+      matrix:
+        node-version: [18.x, 20.x, 22.x]
+
     steps:
     - uses: actions/checkout@v4
-    - name: Use Node.js 16.15
+    - name: Use Node.js ${{ matrix.node-version }}
       uses: actions/setup-node@v4
       with:
-        node-version: 16.15
+        node-version: ${{ matrix.node-version }}
         cache: 'npm'
         registry-url: 'https://npm.pkg.github.com'
-    - run: npm ci
+    - run: npm ci --engine-strict
       env:
         NODE_AUTH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
     - run: npm run format-check -ws
     - run: npm run build -ws
     - run: npm run lint -ws
     - run: npm test -ws
+
+  check-generated:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v4
+    - name: Use Node.js 22.x
+      uses: actions/setup-node@v4
+      with:
+        node-version: 22.x
+        cache: 'npm'
+        registry-url: 'https://npm.pkg.github.com'
+    - run: npm ci
+      env:
+        NODE_AUTH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+    - name: Regenerate JSON files
+      run: |
+        cd languageservice && npm run update-webhooks && cd ..
+    - name: Check for uncommitted changes
+      run: |
+        if ! git diff --exit-code; then
+          echo ""
+          echo "=========================================="
+          echo "ERROR: Generated files are out of date!"
+          echo "=========================================="
+          echo ""
+          echo "Please run the following commands locally and commit the changes:"
+          echo ""
+          echo "  cd languageservice && npm run update-webhooks && cd .."
+          echo "  git add -A && git commit -m 'Regenerate JSON files'"
+          echo ""
+          exit 1
+        fi
+
+  validate-webhooks:
+    runs-on: ubuntu-latest
+    name: Validate webhook optimization
+
+    steps:
+    - uses: actions/checkout@v4
+    - name: Use Node.js 22.x
+      uses: actions/setup-node@v4
+      with:
+        node-version: 22.x
+        cache: 'npm'
+        registry-url: 'https://npm.pkg.github.com'
+    - run: npm ci
+      env:
+        NODE_AUTH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+    - name: Build workspaces
+      run: npm run build -ws
+    - name: Generate full webhooks file
+      run: cd languageservice && npm run update-webhooks
+    - name: Run optimization validation tests
+      run: cd languageservice && npm test -- --testPathPattern=eventPayloads
+    - name: Verify validation tests ran
+      run: |
+        if [ ! -f languageservice/src/context-providers/events/webhooks.full.validation-complete ]; then
+          echo "ERROR: Validation tests did not run!"
+          echo "The webhooks.full.validation-complete marker file was not created."
+          exit 1
+        fi
+        echo "Validation tests completed at: $(cat languageservice/src/context-providers/events/webhooks.full.validation-complete)"

.github/workflows/release.yml

@@ -69,7 +69,7 @@ jobs:
 
       - uses: actions/setup-node@v4
         with:
-          node-version: 16.x
+          node-version: 22.x
           cache: "npm"
           scope: '@actions'
 

.gitignore

@@ -2,4 +2,13 @@
 */dist
 lerna-debug.log
 node_modules
-.DS_Store
+.DS_Store
+
+# Minified JSON (generated at build time)
+*.min.json
+
+# Full webhooks source (generated by update-webhooks, used for validation tests)
+*.full.json
+
+# Validation marker (generated by tests)
+*.validation-complete

README.md

@@ -8,6 +8,10 @@ This repository contains multiple npm packages for working with GitHub Actions w
 - [languageserver](./languageserver) - Language Server for GitHub Actions, hosting the language service for LSP-compatible editors
 - [browser-playground](./browser-playground) - Browser-based playground for the language service
 
+## Documentation
+
+- [JSON Data Files](./docs/json-data-files.md) - How the JSON data files are generated and maintained
+
 ### Note
 
 Thank you for your interest in this GitHub repo, however, right now we are not taking contributions. 

docs/json-data-files.md

@@ -0,0 +1,223 @@
+# JSON Data Files
+
+This document describes the JSON data files used by the language service packages and how they are maintained.
+
+## Overview
+
+The language service uses several JSON files containing schema definitions, webhook payloads, and other metadata. To reduce bundle size, these files are:
+
+1. **Optimized at generation time** — unused events are dropped, unused fields are stripped, shared objects are deduplicated, property names are interned
+2. **Compacted using a space-efficient format** — params use type-based dispatch arrays instead of objects
+3. **Minified at build time** — whitespace is removed to produce `.min.json` files
+
+The source `.json` files are human-readable and checked into the repository. The `.min.json` files are generated during build and gitignored.
+
+## Files
+
+### languageservice
+
+| File | Description |
+|------|-------------|
+| `src/context-providers/events/webhooks.json` | Webhook event payload schemas for autocompletion |
+| `src/context-providers/events/webhooks.objects.json` | Deduplicated shared object definitions referenced by webhooks |
+| `src/context-providers/events/webhooks.strings.json` | Interned property names shared by webhooks and objects |
+| `src/context-providers/events/schedule.json` | Schedule event context data |
+| `src/context-providers/events/workflow_call.json` | Reusable workflow call context data |
+| `src/context-providers/descriptions.json` | Context variable descriptions for hover |
+
+### workflow-parser
+
+| File | Description |
+|------|-------------|
+| `src/workflow-v1.0.json` | Workflow YAML schema definition |
+
+## Generation
+
+### Webhooks and Objects
+
+The `webhooks.json`, `webhooks.objects.json`, and `webhooks.strings.json` files are generated from the [GitHub REST API description](https://github.com/github/rest-api-description):
+
+```bash
+cd languageservice
+npm run update-webhooks
+```
+
+This script:
+1. Fetches webhook schemas from the GitHub API description
+2. **Validates** all events are categorized (fails if new events are found)
+3. **Drops** events that aren't valid workflow triggers (see [Dropped Events](#dropped-events))
+4. **Compacts** params into a space-efficient array format, keeping only `name`, `description`, and `childParamsGroups` (see [Compact Format](#compact-format))
+5. **Deduplicates** shared object definitions into `webhooks.objects.json`
+6. **Interns** duplicate property names into `webhooks.strings.json` (see [String Interning](#string-interning))
+7. Writes the optimized, pretty-printed JSON files
+
+### Handling New Webhook Events
+
+When GitHub adds a new webhook event, the script will fail with an error like:
+
+```
+ERROR: New webhook event(s) detected!
+
+The following events are not categorized:
+  - new_event_name
+
+Action required:
+  1. Check if the event is a valid workflow trigger
+  2. Add the event to DROPPED_EVENTS or KEPT_EVENTS
+```
+
+**To resolve:**
+
+1. Check [Events that trigger workflows](https://docs.github.com/en/actions/writing-workflows/choosing-when-your-workflow-runs/events-that-trigger-workflows)
+
+2. Edit `languageservice/src/context-providers/events/event-filters.json`:
+   - Add to `kept` array if it's a valid workflow trigger
+   - Add to `dropped` array if it's GitHub App or API-only
+
+3. Run `npm run update-webhooks` and commit the changes
+
+#### Viewing Full Unprocessed Data
+
+To see all available fields and events before optimization:
+
+```bash
+npm run update-webhooks -- --all
+```
+
+This generates `webhooks.all.json` and `objects.all.json` (gitignored) containing the complete unprocessed data from the GitHub API.
+
+### Other Files
+
+The other JSON files (`schedule.json`, `workflow_call.json`, `descriptions.json`, `workflow-v1.0.json`) are manually maintained.
+
+## Minification
+
+At build time, all JSON files are minified (whitespace removed) to produce `.min.json` versions:
+
+```bash
+npm run minify-json
+```
+
+This runs automatically via `prebuild` and `pretest` hooks, so you don't need to run it manually.
+
+The code imports the minified versions:
+
+```ts
+import webhooks from "./events/webhooks.min.json"
+import objects from "./events/webhooks.objects.min.json"
+import strings from "./events/webhooks.strings.min.json"
+```
+
+## CI Verification
+
+CI verifies that generated source files are up-to-date:
+
+1. Runs `npm run update-webhooks` to regenerate webhooks.json, webhooks.objects.json, and webhooks.strings.json
+2. Checks for uncommitted changes with `git diff --exit-code`
+
+The `.min.json` files are generated at build time and are not committed to the repository.
+
+If the build fails, run `cd languageservice && npm run update-webhooks` locally and commit the changes.
+
+## Dropped Events
+
+Webhook events that aren't valid workflow `on:` triggers are dropped (e.g., `installation`, `ping`, `member`, etc.). These are GitHub App or API-only events.
+
+See `dropped` array in `src/context-providers/events/event-filters.json` for the full list.
+
+## Compact Format
+
+Params are converted from verbose objects into compact arrays, keeping only the fields needed for autocompletion and hover docs (`name`, `description`, `childParamsGroups`). Unused fields like `type`, `in`, `isRequired`, `enum`, and `default` are discarded.
+
+| Format | Meaning |
+|--------|---------|
+| `"name"` | Name only (no description, no children) |
+| `[name, desc]` | Name + description (arr[1] is a string) |
+| `[name, children]` | Name + children (arr[1] is an array) |
+| `[name, desc, children]` | Name + description + children |
+
+The reader uses `typeof arr[1]` to determine the format: if it's a string, it's a description; if it's an array, it's children.
+
+**Example:**
+
+```json
+// Before (object format)
+{
+  "name": "issue",
+  "description": "The issue itself.",
+  "childParamsGroups": [
+    { "name": "id" },
+    { "name": "title", "description": "Issue title" }
+  ]
+}
+
+// After (compact format)
+["issue", "The issue itself.", [
+  "id",
+  ["title", "Issue title"]
+]]
+```
+
+## String Interning
+
+Property names that appear 2+ times are "interned" into a shared string table (`webhooks.strings.json`). In the compact arrays, these names are replaced with non-negative numeric indices:
+
+```json
+// webhooks.strings.json
+["url", "id", "name", ...]  // Index 0 = "url", 1 = "id", 2 = "name"
+
+// webhooks.json - uses indices instead of strings
+{
+  "push": {
+    "default": {
+      "p": [
+        [0, "The URL..."],  // 0 = "url" from string table
+        [1, "Unique ID"],   // 1 = "id"
+        2                   // 2 = "name" (name-only, no description)
+      ]
+    }
+  }
+}
+```
+
+**How to distinguish indices from other values:**
+
+- **Negative numbers** → Object indices: `-1` = object 0, `-2` = object 1, etc. (formula: `-(index + 1)`)
+- **Non-negative numbers** → String indices (references into `webhooks.strings.json`)
+- **Literal strings** → Singletons (names appearing only once, not interned)
+
+Singletons are kept as literal strings for readability and to avoid the overhead of adding rarely-used names to the string table.
+
+## Deduplication
+
+Shared object definitions are extracted into `webhooks.objects.json` and referenced by negative index:
+
+```json
+// webhooks.objects.json
+[
+  ["url", "The URL"],           // Index 0 (referenced as -1)
+  ["id", "Unique identifier"],  // Index 1 (referenced as -2)
+  [...]
+]
+
+// webhooks.json - negative numbers reference objects
+{
+  "push": {
+    "default": {
+      "p": [-1, -2, ["ref", "The git ref"]]  // -1 = object 0, -2 = object 1
+    }
+  }
+}
+```
+
+This reduces duplication when the same object structure appears in multiple events (e.g., `repository`, `sender`, `organization`).
+
+## Size Reduction
+
+The optimizations achieve approximately 99% file size reduction:
+
+| Stage | Minified | Gzip |
+|-------|----------|------|
+| Original (webhooks.full.json) | 15.8 MB | 968 KB |
+| After optimization (combined) | 152 KB | 15.6 KB |
+| **Reduction** | **99%** | **98%** |

expressions/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@actions/expressions",
-  "version": "0.3.20",
+  "version": "0.3.23",
   "license": "MIT",
   "type": "module",
   "source": "./src/index.ts",
@@ -44,7 +44,7 @@
     "watch": "tsc --build tsconfig.build.json --watch"
   },
   "engines": {
-    "node": ">= 16.15"
+    "node": ">= 18"
   },
   "files": [
     "dist/**/*"

languageserver/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@actions/languageserver",
-  "version": "0.3.20",
+  "version": "0.3.23",
   "description": "Language server for GitHub Actions",
   "license": "MIT",
   "type": "module",
@@ -43,8 +43,8 @@
     "watch": "tsc --build tsconfig.build.json --watch"
   },
   "dependencies": {
-    "@actions/languageservice": "^0.3.20",
+    "@actions/languageservice": "^0.3.23",
-    "@actions/workflow-parser": "^0.3.20",
+    "@actions/workflow-parser": "^0.3.23",
     "@octokit/rest": "^21.1.1",
     "@octokit/types": "^9.0.0",
     "vscode-languageserver": "^8.0.2",
@@ -52,7 +52,7 @@
     "yaml": "^2.1.3"
   },
   "engines": {
-    "node": ">= 16.15"
+    "node": ">= 18"
   },
   "files": [
     "dist/**/*"

languageservice/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@actions/languageservice",
-  "version": "0.3.20",
+  "version": "0.3.23",
   "description": "Language service for GitHub Actions",
   "license": "MIT",
   "type": "module",
@@ -37,22 +37,25 @@
     "format-check": "prettier --check '**/*.ts'",
     "lint": "eslint 'src/**/*.ts'",
     "lint-fix": "eslint --fix 'src/**/*.ts'",
+    "minify-json": "node ../script/minify-json.js src/context-providers/descriptions.json src/context-providers/events/webhooks.json src/context-providers/events/webhooks.objects.json src/context-providers/events/webhooks.strings.json src/context-providers/events/schedule.json src/context-providers/events/workflow_call.json",
+    "prebuild": "npm run minify-json",
     "prepublishOnly": "npm run build && npm run test",
+    "pretest": "npm run minify-json",
     "test": "NODE_OPTIONS=\"--experimental-vm-modules\" jest",
     "test-watch": "NODE_OPTIONS=\"--experimental-vm-modules\" jest --watch",
-    "update-webhooks": "ts-node-esm script/webhooks/index.ts",
+    "update-webhooks": "npx tsx script/webhooks/update-webhooks.ts",
     "watch": "tsc --build tsconfig.build.json --watch"
   },
   "dependencies": {
-    "@actions/expressions": "^0.3.20",
+    "@actions/expressions": "^0.3.23",
-    "@actions/workflow-parser": "^0.3.20",
+    "@actions/workflow-parser": "^0.3.23",
     "vscode-languageserver-textdocument": "^1.0.7",
     "vscode-languageserver-types": "^3.17.2",
     "vscode-uri": "^3.0.8",
     "yaml": "^2.1.1"
   },
   "engines": {
-    "node": ">= 16.15"
+    "node": ">= 18"
   },
   "files": [
     "dist/**/*"

languageservice/script/webhooks/deduplicate.ts

@@ -1,5 +1,38 @@
 import Webhook from "./webhook";
 
+/**
+ * Get the name from a param.
+ * Formats: "name" (string), or [name, ...] (array)
+ */
+function getParamName(param: any): string {
+  if (typeof param === "string") {
+    return param;
+  }
+  if (Array.isArray(param)) {
+    return param[0];
+  }
+  return param.name;
+}
+
+/**
+ * Get params from a webhook action.
+ * Uses 'p' (short key) if present, falls back to 'bodyParameters'
+ */
+function getParams(webhook: any): any[] {
+  return webhook.p || webhook.bodyParameters || [];
+}
+
+/**
+ * Set params on a webhook action using the short key 'p'
+ */
+function setParams(webhook: any, params: any[]): void {
+  if (webhook.p !== undefined) {
+    webhook.p = params;
+  } else {
+    webhook.bodyParameters = params;
+  }
+}
+
 // Store any repeated body parameters in an array
 // and replace them in the webhook with an index in the array
 export function deduplicateWebhooks(webhooks: Record<string, Record<string, Webhook>>): any[] {
@@ -10,10 +43,11 @@ export function deduplicateWebhooks(webhooks: Record<string, Record<string, Webh
   const objectCount: Record<string, number> = {};
 
   for (const webhook of iterateWebhooks(webhooks)) {
-    for (const param of webhook.bodyParameters) {
+    for (const param of getParams(webhook)) {
-      objectsByName[param.name] ||= [];
+      const name = getParamName(param);
-      const index = findOrAdd(param, objectsByName[param.name]);
+      objectsByName[name] ||= [];
-      const key = `${param.name}:${index}`;
+      const index = findOrAdd(param, objectsByName[name]);
+      const key = `${name}:${index}`;
       objectCount[key] ||= 0;
       objectCount[key]++;
     }
@@ -27,18 +61,19 @@ export function deduplicateWebhooks(webhooks: Record<string, Record<string, Webh
 
   for (const webhook of iterateWebhooks(webhooks)) {
     const newParams: any[] = [];
-    for (const param of webhook.bodyParameters) {
+    for (const param of getParams(webhook)) {
-      const index = find(param, objectsByName[param.name]);
+      const name = getParamName(param);
-      const key = `${param.name}:${index}`;
+      const index = find(param, objectsByName[name]);
+      const key = `${name}:${index}`;
       if (objectCount[key] > 1) {
-        newParams.push(indexForParam(param, index, bodyParamIndexMap, duplicatedBodyParams));
+        newParams.push(indexForParam(param, name, index, bodyParamIndexMap, duplicatedBodyParams));
       } else {
         // If an object is only used once, keep it inline
         newParams.push(param);
       }
     }
 
-    webhook.bodyParameters = newParams;
+    setParams(webhook, newParams);
   }
 
   return duplicatedBodyParams;
@@ -74,11 +109,12 @@ function find(param: any, objects: any[]): number {
 
 function indexForParam(
   param: any,
+  paramName: string,
   paramNameIndex: number,
   objectIndexMap: Record<string, number>,
   duplicatedBodyParams: any[]
 ): number {
-  const key = `${param.name}:${paramNameIndex}`;
+  const key = `${paramName}:${paramNameIndex}`;
 
   const existingIndex = objectIndexMap[key];
   if (existingIndex !== undefined) {

languageservice/script/webhooks/index.ts

@@ -1,39 +0,0 @@
-import {promises as fs} from "fs";
-import Webhook from "./webhook.js";
-
-import schemaImport from "rest-api-description/descriptions/api.github.com/dereferenced/api.github.com.deref.json";
-import {deduplicateWebhooks} from "./deduplicate.js";
-const schema = schemaImport as any;
-
-const OUTPUT_PATH = "./src/context-providers/events/webhooks.json";
-const OBJECTS_PATH = "./src/context-providers/events/objects.json";
-
-const rawWebhooks = Object.values(schema.webhooks || schema["x-webhooks"]) as any[];
-if (!rawWebhooks) {
-  throw new Error("No webhooks found in schema");
-}
-
-const webhooks: Webhook[] = [];
-for (const webhook of Object.values(rawWebhooks)) {
-  webhooks.push(new Webhook(webhook.post));
-}
-
-await Promise.all(webhooks.map(webhook => webhook.process()));
-
-// The category is the name of the webhook
-const categorizedWebhooks: Record<string, Record<string, Webhook>> = {};
-for (const webhook of webhooks) {
-  if (!webhook.action) webhook.action = "default";
-
-  if (categorizedWebhooks[webhook.category]) {
-    categorizedWebhooks[webhook.category][webhook.action] = webhook;
-  } else {
-    categorizedWebhooks[webhook.category] = {};
-    categorizedWebhooks[webhook.category][webhook.action] = webhook;
-  }
-}
-
-const objectsArray = deduplicateWebhooks(categorizedWebhooks);
-
-await fs.writeFile(OBJECTS_PATH, JSON.stringify(objectsArray, null, 2));
-await fs.writeFile(OUTPUT_PATH, JSON.stringify(categorizedWebhooks, null, 2));

languageservice/script/webhooks/update-webhooks.ts

@@ -0,0 +1,291 @@
+import {promises as fs} from "fs";
+import Webhook from "./webhook.js";
+
+import schemaImport from "rest-api-description/descriptions/api.github.com/dereferenced/api.github.com.deref.json";
+import {deduplicateWebhooks} from "./deduplicate.js";
+import eventFilters from "../../src/context-providers/events/event-filters.json";
+const schema = schemaImport as any;
+
+const DROPPED_EVENTS = new Set(eventFilters.dropped);
+const KEPT_EVENTS = new Set(eventFilters.kept);
+
+const OUTPUT_PATH = "./src/context-providers/events/webhooks.json";
+const OBJECTS_PATH = "./src/context-providers/events/webhooks.objects.json";
+const STRINGS_PATH = "./src/context-providers/events/webhooks.strings.json";
+const FULL_OUTPUT_PATH = "./src/context-providers/events/webhooks.full.json";
+
+/**
+ * Fields discarded from each event action object (top level only).
+ * Body parameters are compacted to only keep name, description, and childParamsGroups.
+ */
+const EVENT_ACTION_FIELDS = ["description", "summary", "availability", "category", "action"];
+
+/**
+ * Convert a bodyParameter object to compact array format.
+ *
+ * Format (type-based dispatch):
+ *   - "name"                      - name only (just a string)
+ *   - [name, desc]                - name + description (desc is string)
+ *   - [name, [...children]]       - name + children (arr[1] is array)
+ *   - [name, desc, [...children]] - name + description + children
+ *
+ * The reader uses typeof to determine the meaning:
+ *   - string -> name only
+ *   - array with string arr[1] -> name + description
+ *   - array with array arr[1] -> name + children
+ */
+function compactParam(param: any): any {
+  if (typeof param !== "object" || param === null) {
+    return param;
+  }
+
+  const name: string = param.name;
+  const desc: string | undefined = param.description;
+  const children: any[] | undefined = param.childParamsGroups;
+
+  const hasDesc = desc && desc.length > 0;
+  const hasChildren = children && children.length > 0;
+
+  if (hasDesc && hasChildren) {
+    return [name, desc, children.map(compactParam)];
+  } else if (hasChildren) {
+    return [name, children.map(compactParam)];
+  } else if (hasDesc) {
+    return [name, desc];
+  } else {
+    return name; // Just the string, not wrapped in array
+  }
+}
+
+/**
+ * Convert event action data to compact format.
+ */
+function compactEventAction(action: any): any {
+  const result: any = {};
+  for (const [key, value] of Object.entries(action)) {
+    if (EVENT_ACTION_FIELDS.includes(key)) {
+      continue; // Discard this field
+    }
+    if (key === "bodyParameters" && Array.isArray(value)) {
+      // Use short key 'p' for params
+      result["p"] = value.map((p: any) => (typeof p === "number" ? p : compactParam(p)));
+    } else {
+      result[key] = value;
+    }
+  }
+  return result;
+}
+
+/**
+ * Convert all webhooks to compact format.
+ * Structure: { eventName: { actionName: { ...fields } } }
+ */
+function compactWebhooks(webhooks: Record<string, Record<string, any>>): Record<string, Record<string, any>> {
+  const result: Record<string, Record<string, any>> = {};
+  for (const [eventName, actions] of Object.entries(webhooks)) {
+    result[eventName] = {};
+    for (const [actionName, actionData] of Object.entries(actions)) {
+      result[eventName][actionName] = compactEventAction(actionData);
+    }
+  }
+  return result;
+}
+
+const rawWebhooks = Object.values(schema.webhooks || schema["x-webhooks"]) as any[];
+if (!rawWebhooks) {
+  throw new Error("No webhooks found in schema");
+}
+
+const webhooks: Webhook[] = [];
+for (const webhook of Object.values(rawWebhooks)) {
+  webhooks.push(new Webhook(webhook.post));
+}
+
+await Promise.all(webhooks.map(webhook => webhook.process()));
+
+// Check for unknown events (not in DROPPED_EVENTS or KEPT_EVENTS)
+const unknownEvents: string[] = [];
+for (const webhook of webhooks) {
+  if (!DROPPED_EVENTS.has(webhook.category) && !KEPT_EVENTS.has(webhook.category)) {
+    if (!unknownEvents.includes(webhook.category)) {
+      unknownEvents.push(webhook.category);
+    }
+  }
+}
+
+if (unknownEvents.length > 0) {
+  console.error("");
+  console.error("══════════════════════════════════════════════════════════════════");
+  console.error("ERROR: New webhook event(s) detected!");
+  console.error("══════════════════════════════════════════════════════════════════");
+  console.error("");
+  console.error("The following events are not categorized:");
+  for (const event of unknownEvents.sort()) {
+    console.error(`  - ${event}`);
+  }
+  console.error("");
+  console.error("Action required:");
+  console.error("  1. Check if the event is a valid workflow trigger:");
+  console.error(
+    "     https://docs.github.com/en/actions/writing-workflows/choosing-when-your-workflow-runs/events-that-trigger-workflows"
+  );
+  console.error("");
+  console.error("  2. Add the event to 'dropped' or 'kept' array in:");
+  console.error("     languageservice/src/context-providers/events/event-filters.json");
+  console.error("");
+  console.error("  3. See docs/json-data-files.md for more details.");
+  console.error("");
+  process.exit(1);
+}
+
+// Build full webhooks (all events, no transformations) for validation tests
+const fullWebhooks: Record<string, Record<string, Webhook>> = {};
+for (const webhook of webhooks) {
+  if (!webhook.action) webhook.action = "default";
+
+  if (fullWebhooks[webhook.category]) {
+    fullWebhooks[webhook.category][webhook.action] = webhook;
+  } else {
+    fullWebhooks[webhook.category] = {};
+    fullWebhooks[webhook.category][webhook.action] = webhook;
+  }
+}
+
+// Write full version (before any optimizations)
+await fs.writeFile(FULL_OUTPUT_PATH, JSON.stringify(fullWebhooks, null, 2));
+console.log(`Wrote ${FULL_OUTPUT_PATH} (${Object.keys(fullWebhooks).length} events, unoptimized)`);
+
+// The category is the name of the webhook
+const categorizedWebhooks: Record<string, Record<string, Webhook>> = {};
+for (const webhook of webhooks) {
+  if (!webhook.action) webhook.action = "default";
+
+  // Drop unused events
+  if (DROPPED_EVENTS.has(webhook.category)) {
+    continue;
+  }
+
+  if (categorizedWebhooks[webhook.category]) {
+    categorizedWebhooks[webhook.category][webhook.action] = webhook;
+  } else {
+    categorizedWebhooks[webhook.category] = {};
+    categorizedWebhooks[webhook.category][webhook.action] = webhook;
+  }
+}
+
+// Convert to compact format before deduplication
+const compactedWebhooks = compactWebhooks(categorizedWebhooks);
+
+// Deduplicate after compacting
+const objectsArray = deduplicateWebhooks(compactedWebhooks);
+
+// ============================================================================
+// String Interning (Phase 3)
+// ============================================================================
+// Intern duplicate property names to reduce file size.
+// Names appearing 2+ times are stored in a string table and referenced by index.
+// Singleton names stay as literal strings for readability.
+
+/**
+ * Collect all property names from params (for frequency counting)
+ */
+function collectNames(param: any, counts: Map<string, number>): void {
+  if (typeof param === "number") return;
+  if (typeof param === "string") {
+    counts.set(param, (counts.get(param) || 0) + 1);
+    return;
+  }
+  if (Array.isArray(param)) {
+    const name = param[0] as string;
+    counts.set(name, (counts.get(name) || 0) + 1);
+    const children = Array.isArray(param[1]) ? param[1] : param[2];
+    if (children) children.forEach((c: any) => collectNames(c, counts));
+  }
+}
+
+/**
+ * Replace duplicate names with indices into the string table.
+ * Object references use negative indices: objectIndex -> -(objectIndex + 1)
+ * String references use non-negative indices: stringIndex -> stringIndex
+ *
+ * @param param - The param to process
+ * @param nameToIndex - Map from name to string table index
+ */
+function internNames(param: any, nameToIndex: Map<string, number>): any {
+  // Object reference (already a number from deduplication) -> make negative
+  if (typeof param === "number") return -(param + 1);
+
+  // String -> intern if in table, otherwise keep as literal
+  if (typeof param === "string") {
+    const idx = nameToIndex.get(param);
+    return idx !== undefined ? idx : param;
+  }
+
+  if (Array.isArray(param)) {
+    const name = param[0] as string;
+    const idx = nameToIndex.get(name);
+    const internedName = idx !== undefined ? idx : name;
+
+    // Handle different array formats
+    if (typeof param[1] === "string" && !Array.isArray(param[1])) {
+      // [name, desc] or [name, desc, children]
+      if (param.length === 2) {
+        return [internedName, param[1]];
+      } else {
+        return [internedName, param[1], (param[2] as any[]).map((c: any) => internNames(c, nameToIndex))];
+      }
+    } else if (Array.isArray(param[1])) {
+      // [name, children]
+      return [internedName, param[1].map((c: any) => internNames(c, nameToIndex))];
+    }
+    // Shouldn't happen, but fallback
+    return [internedName, ...param.slice(1)];
+  }
+  return param;
+}
+
+// Pass 1: Count all names
+const nameCounts = new Map<string, number>();
+objectsArray.forEach((obj: any) => collectNames(obj, nameCounts));
+for (const event of Object.values(compactedWebhooks)) {
+  for (const action of Object.values(event as Record<string, any>)) {
+    if (action.p) action.p.forEach((p: any) => collectNames(p, nameCounts));
+  }
+}
+
+// Build string table from duplicates, sorted by frequency (most common first = smaller indices)
+const sortedNames = [...nameCounts.entries()].filter(([, count]) => count >= 2).sort((a, b) => b[1] - a[1]);
+const stringTable = sortedNames.map(([name]) => name);
+const nameToIndex = new Map(stringTable.map((name, i) => [name, i]));
+
+console.log(
+  `String table: ${stringTable.length} interned names (${nameCounts.size - stringTable.length} singletons kept inline)`
+);
+
+// Pass 2: Intern names in objects and webhooks
+// Objects use negative indices, strings use non-negative indices
+const internedObjects = objectsArray.map((obj: any) => internNames(obj, nameToIndex));
+const internedWebhooks: Record<string, Record<string, any>> = {};
+for (const [eventName, actions] of Object.entries(compactedWebhooks)) {
+  internedWebhooks[eventName] = {};
+  for (const [actionName, actionData] of Object.entries(actions as Record<string, any>)) {
+    internedWebhooks[eventName][actionName] = {
+      p: actionData.p.map((p: any) => internNames(p, nameToIndex))
+    };
+  }
+}
+
+// Write optimized output with separate string table
+// Format: webhooks.strings.json has string table, webhooks.json/webhooks.objects.json reference by index
+const finalOutput = {
+  "//": "Generated file - refer to docs/json-data-files.md for format documentation",
+  ...internedWebhooks
+};
+
+await fs.writeFile(STRINGS_PATH, JSON.stringify(stringTable, null, 2));
+await fs.writeFile(OBJECTS_PATH, JSON.stringify(internedObjects, null, 2));
+await fs.writeFile(OUTPUT_PATH, JSON.stringify(finalOutput, null, 2));
+
+console.log(`Wrote ${STRINGS_PATH} (${stringTable.length} interned strings)`);
+console.log(`Wrote ${OUTPUT_PATH} (${Object.keys(compactedWebhooks).length} events)`);
+console.log(`Wrote ${OBJECTS_PATH} (${internedObjects.length} objects)`);

languageservice/src/complete.expressions.test.ts

@@ -1268,7 +1268,7 @@ jobs:
 on: push
 jobs:
   a:
-    uses: ./reusable-workflow-with-outputs.yaml
+    uses: ./.github/workflows/reusable-workflow-with-outputs.yaml
   b:
     needs: [a]
     runs-on: ubuntu-latest

languageservice/src/complete.reusable-workflows.test.ts

@@ -21,7 +21,7 @@ on: push
 
 jobs:
   build:
-    uses: ./reusable-workflow-with-inputs.yaml
+    uses: ./.github/workflows/reusable-workflow-with-inputs.yaml
     with:
       |
 `;
@@ -49,7 +49,7 @@ on: push
 
 jobs:
   build:
-    uses: ./reusable-workflow-with-inputs.yaml
+    uses: ./.github/workflows/reusable-workflow-with-inputs.yaml
     with:
       username: monalisa
       |
@@ -74,7 +74,7 @@ on: push
 
 jobs:
   build:
-    uses: ./reusable-workflow-with-inputs.yaml
+    uses: ./.github/workflows/reusable-workflow-with-inputs.yaml
     secrets:
       |
 `;
@@ -102,7 +102,7 @@ on: push
 
 jobs:
   build:
-    uses: ./reusable-workflow-with-inputs.yaml
+    uses: ./.github/workflows/reusable-workflow-with-inputs.yaml
     secrets: |
 `;
     const result = await complete(...getPositionFromCursor(input), {fileProvider: testFileProvider});
@@ -117,7 +117,7 @@ on: push
 
 jobs:
   build:
-    uses: ./reusable-workflow-with-inputs.yaml
+    uses: ./.github/workflows/reusable-workflow-with-inputs.yaml
     secrets:
       envPAT: "myPAT"
       |

languageservice/src/context-providers/descriptions.ts

@@ -1,4 +1,4 @@
-import descriptions from "./descriptions.json";
+import descriptions from "./descriptions.min.json";
 
 export const RootContext = "root";
 const FunctionContext = "functions";

languageservice/src/context-providers/events/event-filters.json

@@ -0,0 +1,75 @@
+{
+  "dropped": [
+    "branch_protection_configuration",
+    "code_scanning_alert",
+    "commit_comment",
+    "custom_property",
+    "custom_property_values",
+    "dependabot_alert",
+    "deploy_key",
+    "github_app_authorization",
+    "installation",
+    "installation_repositories",
+    "installation_target",
+    "marketplace_purchase",
+    "member",
+    "membership",
+    "merge_group",
+    "meta",
+    "org_block",
+    "organization",
+    "package",
+    "personal_access_token_request",
+    "ping",
+    "repository",
+    "repository_advisory",
+    "repository_ruleset",
+    "secret_scanning_alert",
+    "secret_scanning_alert_location",
+    "security_advisory",
+    "security_and_analysis",
+    "sponsorship",
+    "star",
+    "team",
+    "team_add"
+  ],
+  "kept": [
+    "branch_protection_rule",
+    "check_run",
+    "check_suite",
+    "create",
+    "delete",
+    "deployment",
+    "deployment_status",
+    "discussion",
+    "discussion_comment",
+    "fork",
+    "gollum",
+    "issue_comment",
+    "issues",
+    "label",
+    "milestone",
+    "page_build",
+    "project",
+    "project_card",
+    "project_column",
+    "projects_v2",
+    "projects_v2_item",
+    "public",
+    "pull_request",
+    "pull_request_review",
+    "pull_request_review_comment",
+    "pull_request_review_thread",
+    "push",
+    "registry_package",
+    "release",
+    "repository_dispatch",
+    "repository_import",
+    "repository_vulnerability_alert",
+    "status",
+    "watch",
+    "workflow_dispatch",
+    "workflow_job",
+    "workflow_run"
+  ]
+}

languageservice/src/context-providers/events/eventPayloads.test.ts

@@ -0,0 +1,277 @@
+import {existsSync} from "fs";
+import {fileURLToPath} from "url";
+import {dirname, join} from "path";
+import {data, DescriptionDictionary, DescriptionPair, isDescriptionDictionary} from "@actions/expressions";
+import {getEventPayload, getSupportedEventTypes} from "./eventPayloads";
+import eventFilters from "./event-filters.json";
+
+const DROPPED_EVENTS = new Set(eventFilters.dropped);
+
+// Check if full webhooks file exists (generated by npm run update-webhooks)
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
+const fullWebhooksPath = join(__dirname, "webhooks.full.json");
+const hasFullWebhooks = existsSync(fullWebhooksPath);
+
+type Param = {
+  name: string;
+  description?: string;
+  childParamsGroups?: Param[];
+};
+
+type FullAction = {
+  action?: string;
+  bodyParameters?: Param[];
+};
+
+type FullWebhooks = {
+  [event: string]: {
+    [action: string]: FullAction;
+  };
+};
+
+describe("eventPayloads", () => {
+  describe("getSupportedEventTypes", () => {
+    it("returns action types for push event", () => {
+      const types = getSupportedEventTypes("push");
+      expect(types).toContain("default");
+    });
+
+    it("returns action types for issues event", () => {
+      const types = getSupportedEventTypes("issues");
+      expect(types.length).toBeGreaterThan(1);
+      expect(types).toContain("opened");
+      expect(types).toContain("closed");
+    });
+  });
+
+  describe("getEventPayload", () => {
+    it("returns payload for push event", () => {
+      const payload = getEventPayload("push", "default");
+      expect(payload).toBeDefined();
+
+      // Verify common fields exist
+      expect(payload?.get("ref")).toBeDefined();
+      expect(payload?.get("repository")).toBeDefined();
+      expect(payload?.get("sender")).toBeDefined();
+    });
+
+    it("returns payload for issues event", () => {
+      const payload = getEventPayload("issues", "opened");
+      expect(payload).toBeDefined();
+
+      expect(payload?.get("action")).toBeDefined();
+      expect(payload?.get("issue")).toBeDefined();
+      expect(payload?.get("repository")).toBeDefined();
+    });
+
+    it("preserves descriptions for hover documentation", () => {
+      // This test ensures bodyParameters[].description is not stripped
+      // during JSON optimization. The description field is used for hover
+      // documentation in the workflow editor.
+      const payload = getEventPayload("push", "default");
+      expect(payload).toBeDefined();
+
+      // Get the description for a well-known field
+      // repository should have a description like "A repository on GitHub"
+      const repoDescription = payload?.getDescription("repository");
+      expect(repoDescription).toBeDefined();
+      expect(repoDescription?.length).toBeGreaterThan(0);
+
+      // sender should have a description
+      const senderDescription = payload?.getDescription("sender");
+      expect(senderDescription).toBeDefined();
+      expect(senderDescription?.length).toBeGreaterThan(0);
+    });
+
+    it("preserves childParamsGroups for nested property access", () => {
+      // This test ensures bodyParameters[].childParamsGroups is not stripped
+      // during JSON optimization. childParamsGroups defines nested properties
+      // used for autocompletion like github.event.repository.owner.login
+      const payload = getEventPayload("push", "default");
+      expect(payload).toBeDefined();
+
+      // repository has nested properties like owner, license, etc.
+      const repository = payload?.get("repository") as DescriptionDictionary | undefined;
+      expect(repository).toBeDefined();
+
+      // repository.owner should exist (nested via childParamsGroups)
+      const owner = repository?.get("owner") as DescriptionDictionary | undefined;
+      expect(owner).toBeDefined();
+
+      // repository.owner.login should exist (deeply nested)
+      const login = owner?.get("login");
+      expect(login).toBeDefined();
+    });
+
+    it("preserves name fields for property identification", () => {
+      // This test ensures bodyParameters[].name is not stripped
+      // during JSON optimization. The name field identifies each property.
+      const payload = getEventPayload("issues", "opened");
+      expect(payload).toBeDefined();
+
+      // Verify well-known property names exist
+      expect(payload?.get("action")).toBeDefined();
+      expect(payload?.get("issue")).toBeDefined();
+      expect(payload?.get("repository")).toBeDefined();
+      expect(payload?.get("sender")).toBeDefined();
+
+      // Verify nested property names work
+      const issue = payload?.get("issue") as DescriptionDictionary | undefined;
+      expect(issue?.get("title")).toBeDefined();
+      expect(issue?.get("number")).toBeDefined();
+      expect(issue?.get("user")).toBeDefined();
+    });
+
+    it("returns undefined for unknown event", () => {
+      const payload = getEventPayload("not_a_real_event", "default");
+      expect(payload).toBeUndefined();
+    });
+  });
+});
+
+// Optimization validation tests - only run if webhooks.full.json exists
+// This file is generated by: npm run update-webhooks
+// In CI, a separate job runs these tests after generating the file
+const describeIfFullExists = hasFullWebhooks ? describe : describe.skip;
+
+// Marker file path - written after validation tests complete
+const fullValidationMarkerPath = join(__dirname, "webhooks.full.validation-complete");
+
+describeIfFullExists("optimization validation", () => {
+  let keptWebhooks: FullWebhooks;
+
+  beforeAll(async () => {
+    // Dynamically import the full webhooks file using fs to avoid TS module resolution
+    const {readFileSync} = await import("fs");
+    const fullWebhooks = JSON.parse(readFileSync(fullWebhooksPath, "utf-8")) as FullWebhooks;
+
+    // Filter to only kept events
+    keptWebhooks = {};
+    for (const [event, actions] of Object.entries(fullWebhooks)) {
+      if (!DROPPED_EVENTS.has(event)) {
+        keptWebhooks[event] = actions;
+      }
+    }
+  });
+
+  afterAll(async () => {
+    // Write marker file to prove validation tests ran
+    const {writeFileSync} = await import("fs");
+    writeFileSync(fullValidationMarkerPath, new Date().toISOString());
+  });
+
+  /**
+   * Build a DescriptionDictionary from raw params (same logic as eventPayloads.ts)
+   */
+  function buildFromParams(params: Param[]): DescriptionDictionary {
+    const d = new DescriptionDictionary();
+    for (const param of params) {
+      if (param.childParamsGroups && param.childParamsGroups.length > 0) {
+        const child = buildFromParams(param.childParamsGroups);
+        d.add(param.name, child, param.description);
+      } else {
+        // Match the behavior in eventPayloads.ts - don't overwrite existing
+        if (!d.get(param.name)) {
+          d.add(param.name, new data.Null(), param.description);
+        }
+      }
+    }
+    return d;
+  }
+
+  /**
+   * Compare two DescriptionDictionary structures recursively
+   */
+  function compareStructures(full: DescriptionDictionary, optimized: DescriptionDictionary, path: string): string[] {
+    const errors: string[] = [];
+
+    const fullPairs = full.pairs();
+    const optimizedPairs = optimized.pairs();
+
+    const fullKeys = new Set(fullPairs.map((p: DescriptionPair) => p.key));
+    const optimizedKeys = new Set(optimizedPairs.map((p: DescriptionPair) => p.key));
+
+    // Check for missing keys in optimized
+    for (const key of fullKeys) {
+      if (!optimizedKeys.has(key)) {
+        errors.push(`Missing key in optimized: ${path}.${key}`);
+      }
+    }
+
+    // Check for extra keys in optimized
+    for (const key of optimizedKeys) {
+      if (!fullKeys.has(key)) {
+        errors.push(`Extra key in optimized: ${path}.${key}`);
+      }
+    }
+
+    // Compare descriptions and recurse into nested structures
+    for (const fullPair of fullPairs) {
+      const optimizedValue = optimized.get(fullPair.key);
+      if (optimizedValue === undefined) continue;
+
+      // Compare descriptions
+      const fullDesc = full.getDescription(fullPair.key) ?? "";
+      const optimizedDesc = optimized.getDescription(fullPair.key) ?? "";
+      if (fullDesc !== optimizedDesc) {
+        errors.push(
+          `Description mismatch at ${path}.${fullPair.key}: ` + `full="${fullDesc}" vs optimized="${optimizedDesc}"`
+        );
+      }
+
+      // Recurse into nested dictionaries
+      if (isDescriptionDictionary(fullPair.value) && isDescriptionDictionary(optimizedValue)) {
+        errors.push(...compareStructures(fullPair.value, optimizedValue, `${path}.${fullPair.key}`));
+      }
+    }
+
+    return errors;
+  }
+
+  it("optimized webhooks match full source for all events and actions", () => {
+    const allErrors: string[] = [];
+
+    for (const [event, actions] of Object.entries(keptWebhooks)) {
+      for (const [action, actionData] of Object.entries(actions)) {
+        // Build from full source (use bodyParameters, may be undefined)
+        const params = actionData.bodyParameters || [];
+        const fullPayload = buildFromParams(params);
+
+        // Get from optimized (deduplicated) source
+        const optimizedPayload = getEventPayload(event, action);
+
+        if (!optimizedPayload) {
+          allErrors.push(`Missing optimized payload for ${event}.${action}`);
+          continue;
+        }
+
+        const errors = compareStructures(fullPayload, optimizedPayload, `${event}.${action}`);
+        allErrors.push(...errors);
+      }
+    }
+
+    if (allErrors.length > 0) {
+      fail(
+        `Optimization validation failed:\n${allErrors.slice(0, 20).join("\n")}` +
+          (allErrors.length > 20 ? `\n... and ${allErrors.length - 20} more errors` : "")
+      );
+    }
+  });
+
+  it("all full source events are present in optimized version", () => {
+    for (const event of Object.keys(keptWebhooks)) {
+      const types = getSupportedEventTypes(event);
+      expect(types.length).toBeGreaterThan(0);
+    }
+  });
+
+  it("all full source actions are present in optimized version", () => {
+    for (const [event, actions] of Object.entries(keptWebhooks)) {
+      for (const action of Object.keys(actions)) {
+        const payload = getEventPayload(event, action);
+        expect(payload).toBeDefined();
+      }
+    }
+  });
+});

languageservice/src/context-providers/events/eventPayloads.ts

@@ -1,10 +1,11 @@
 import {data, DescriptionDictionary} from "@actions/expressions";
 
-import webhookObjects from "./objects.json";
+import webhooksData from "./webhooks.min.json";
-import webhooks from "./webhooks.json";
+import objectsData from "./webhooks.objects.min.json";
+import stringsData from "./webhooks.strings.min.json";
 
-import schedule from "./schedule.json";
+import schedule from "./schedule.min.json";
-import workflow_call from "./workflow_call.json";
+import workflow_call from "./workflow_call.min.json";
 
 const customEventPayloads: {[name: string]: unknown} = {
   schedule,
@@ -49,9 +50,22 @@ type Param = {
 };
 
 /**
- * A full {@link Param} or an index into the objects array for deduplicated parameters
+ * Compact format for params (written by update-webhooks.ts).
+ *
+ * Names can be interned (number = index into string table) or literal strings.
+ * Type-based dispatch:
+ *   - number                   - interned name only (index into string table)
+ *   - "name"                   - literal name only (singleton, not interned)
+ *   - [name, desc]             - name + description (name is number or string, desc is string)
+ *   - [name, [...children]]    - name + children (arr[1] is array)
+ *   - [name, desc, [...children]] - name + description + children
  */
-type DeduplicatedParam = Param | number;
+type InternedName = number | string;
+type CompactParam =
+  | InternedName
+  | [InternedName, string]
+  | [InternedName, CompactParam[]]
+  | [InternedName, string, CompactParam[]];
 
 type WebhookPayload = {
   descriptionHtml: string;
@@ -65,17 +79,33 @@ type Webhooks = {
   };
 };
 
-type DeduplicatedWebhooks = {
+/**
-  [name: string]: {
+ * Webhooks data format after optimization:
-    [action: string]: WebhookPayload & {
+ * {
-      bodyParameters: DeduplicatedParam[];
+ *   [event]: { [action]: { p: CompactParam[] } }
-    };
+ * }
-  };
+ *
+ * String table and objects are loaded from separate files.
+ */
+type WebhooksData = {
+  [key: string]: {[action: string]: {p: CompactParam[]}};
 };
 
 /* eslint-disable @typescript-eslint/no-unsafe-assignment, @typescript-eslint/no-explicit-any */
-const dedupedWebhookPayloads: DeduplicatedWebhooks = webhooks as any;
+const webhooksJson: WebhooksData = webhooksData as any;
-const objects: Param[] = webhookObjects as any;
+const objectsJson: CompactParam[] = objectsData as any;
+
+// String table and objects are in separate files
+const stringTable: string[] = stringsData;
+const objects: CompactParam[] = objectsJson;
+
+// Build event payloads map (skip "//" comment key)
+const dedupedWebhookPayloads: {[event: string]: {[action: string]: {p: CompactParam[]}}} = {};
+for (const [key, value] of Object.entries(webhooksJson)) {
+  if (key !== "//" && typeof value === "object" && value !== null) {
+    dedupedWebhookPayloads[key] = value as {[action: string]: {p: CompactParam[]}};
+  }
+}
 /* eslint-enable @typescript-eslint/no-unsafe-assignment, @typescript-eslint/no-explicit-any */
 
 // Hydrated webhook payloads
@@ -169,10 +199,14 @@ function getWebhookPayload(event: string, action: string): WebhookPayload | unde
     return undefined;
   }
 
+  // Get params from 'p' (compact format)
+  const dedupedParams = deduplicatedPayload.p || [];
+
   // Recreate the full payload and store it for reuse
-  const params = deduplicatedPayload.bodyParameters.map(p => fullParam(p));
+  const params = dedupedParams.map(p => fullParam(p));
   const payload = {
-    ...deduplicatedPayload,
+    descriptionHtml: "",
+    summaryHtml: "",
     bodyParameters: params
   };
   webhookPayloads[event] ||= {};
@@ -180,13 +214,65 @@ function getWebhookPayload(event: string, action: string): WebhookPayload | unde
   return payload;
 }
 
-function fullParam(dedupedParam: DeduplicatedParam): Param {
+/**
-  if (typeof dedupedParam === "number") {
+ * Resolve an interned name (non-negative number -> string table lookup) or return literal string
-    if (dedupedParam >= objects.length) {
+ */
-      throw new Error(`Unknown object ${dedupedParam}`);
+function resolveName(name: InternedName): string {
+  if (typeof name === "number") {
+    if (name < 0 || name >= stringTable.length) {
+      throw new Error(`Unknown interned name index ${name}`);
     }
-    return objects[dedupedParam];
+    return stringTable[name];
+  }
+  return name;
+}
+
+/**
+ * Convert a deduplicated param to a full Param.
+ *
+ * Compact format (type-based dispatch):
+ *   - negative number          - object index: -(n + 1) -> objects[-n - 1]
+ *   - non-negative number      - interned string index -> stringTable[n]
+ *   - "name"                   - literal name only (singleton, not interned)
+ *   - [name, desc]             - name + description (name can be number or string)
+ *   - [name, [...children]]    - name + children (arr[1] is array)
+ *   - [name, desc, [...children]] - name + description + children
+ */
+function fullParam(dedupedParam: CompactParam): Param {
+  // Negative number -> object index
+  if (typeof dedupedParam === "number" && dedupedParam < 0) {
+    const objectIndex = -(dedupedParam + 1);
+    if (objectIndex >= objects.length) {
+      throw new Error(`Unknown object index ${objectIndex} (from ${dedupedParam})`);
+    }
+    return fullParam(objects[objectIndex]);
   }
 
-  return dedupedParam;
+  // Non-negative number or literal string -> name only
+  if (typeof dedupedParam === "number" || typeof dedupedParam === "string") {
+    return {
+      name: resolveName(dedupedParam),
+      description: ""
+    } as Param;
+  }
+
+  // Compact array format -> convert to Param object
+  if (Array.isArray(dedupedParam)) {
+    const arr = dedupedParam;
+    const name = resolveName(arr[0]);
+
+    // Type-based dispatch: if arr[1] is string -> description, if array -> children
+    const description = typeof arr[1] === "string" ? arr[1] : "";
+    // arr[1] is children if it's an array, otherwise arr[2] is children (if it exists and is an array)
+    const childrenArr = Array.isArray(arr[1]) ? arr[1] : Array.isArray(arr[2]) ? arr[2] : undefined;
+    const childParamsGroups = childrenArr ? childrenArr.map(c => fullParam(c)) : undefined;
+
+    return {
+      name,
+      description,
+      childParamsGroups
+    } as Param;
+  }
+
+  throw new Error(`Unexpected param format: ${JSON.stringify(dedupedParam)}`);
 }

languageservice/src/context-providers/events/webhooks.strings.json

@@ -0,0 +1,416 @@
+[
+  "url",
+  "id",
+  "node_id",
+  "html_url",
+  "name",
+  "events_url",
+  "avatar_url",
+  "login",
+  "repos_url",
+  "type",
+  "gravatar_id",
+  "followers_url",
+  "following_url",
+  "gists_url",
+  "starred_url",
+  "subscriptions_url",
+  "organizations_url",
+  "received_events_url",
+  "site_admin",
+  "email",
+  "deleted",
+  "created_at",
+  "description",
+  "updated_at",
+  "href",
+  "labels_url",
+  "comments_url",
+  "number",
+  "user",
+  "statuses_url",
+  "owner",
+  "commits_url",
+  "state",
+  "open_issues",
+  "sha",
+  "title",
+  "ref",
+  "body",
+  "hooks_url",
+  "issues_url",
+  "full_name",
+  "private",
+  "fork",
+  "archive_url",
+  "assignees_url",
+  "blobs_url",
+  "branches_url",
+  "collaborators_url",
+  "compare_url",
+  "contents_url",
+  "contributors_url",
+  "deployments_url",
+  "downloads_url",
+  "forks_url",
+  "git_commits_url",
+  "git_refs_url",
+  "git_tags_url",
+  "issue_comment_url",
+  "issue_events_url",
+  "keys_url",
+  "languages_url",
+  "merges_url",
+  "milestones_url",
+  "notifications_url",
+  "pulls_url",
+  "releases_url",
+  "stargazers_url",
+  "subscribers_url",
+  "subscription_url",
+  "tags_url",
+  "teams_url",
+  "trees_url",
+  "slug",
+  "size",
+  "repo",
+  "closed_at",
+  "permissions",
+  "archived",
+  "comments",
+  "homepage",
+  "license",
+  "git_url",
+  "ssh_url",
+  "clone_url",
+  "mirror_url",
+  "svn_url",
+  "language",
+  "forks_count",
+  "stargazers_count",
+  "watchers_count",
+  "default_branch",
+  "open_issues_count",
+  "is_template",
+  "topics",
+  "has_issues",
+  "has_projects",
+  "has_wiki",
+  "has_pages",
+  "has_downloads",
+  "disabled",
+  "visibility",
+  "pushed_at",
+  "forks",
+  "delete_branch_on_merge",
+  "allow_forking",
+  "watchers",
+  "allow_rebase_merge",
+  "allow_squash_merge",
+  "allow_auto_merge",
+  "allow_update_branch",
+  "allow_merge_commit",
+  "from",
+  "web_commit_signoff_required",
+  "author_association",
+  "label",
+  "labels",
+  "key",
+  "admin",
+  "pull",
+  "triage",
+  "push",
+  "maintain",
+  "draft",
+  "public",
+  "commits",
+  "organization",
+  "spdx_id",
+  "master_branch",
+  "active_lock_reason",
+  "locked",
+  "review_comments",
+  "use_squash_pr_title_as_default",
+  "squash_merge_commit_title",
+  "squash_merge_commit_message",
+  "merge_commit_title",
+  "merge_commit_message",
+  "role_name",
+  "creator",
+  "stargazers",
+  "milestone",
+  "members_url",
+  "statuses",
+  "assignee",
+  "assignees",
+  "permission",
+  "privacy",
+  "repositories_url",
+  "base",
+  "status",
+  "head",
+  "reactions",
+  "+1",
+  "-1",
+  "confused",
+  "eyes",
+  "heart",
+  "hooray",
+  "laugh",
+  "rocket",
+  "total_count",
+  "diff_url",
+  "merged_at",
+  "patch_url",
+  "changes",
+  "due_on",
+  "repository_url",
+  "color",
+  "issue",
+  "closed_issues",
+  "pull_request",
+  "conclusion",
+  "default",
+  "_links",
+  "html",
+  "author",
+  "self",
+  "pull_requests",
+  "issue_url",
+  "has_discussions",
+  "metadata",
+  "date",
+  "review_comment",
+  "auto_merge",
+  "merge_commit_sha",
+  "requested_reviewers",
+  "requested_teams",
+  "review_comment_url",
+  "review_comments_url",
+  "starred_at",
+  "external_url",
+  "issues",
+  "checks",
+  "contents",
+  "deployments",
+  "events",
+  "head_sha",
+  "username",
+  "performed_via_github_app",
+  "timeline_url",
+  "additions",
+  "changed_files",
+  "deletions",
+  "maintainer_can_modify",
+  "mergeable",
+  "mergeable_state",
+  "merged",
+  "merged_by",
+  "rebaseable",
+  "head_branch",
+  "completed_at",
+  "started_at",
+  "parent",
+  "commit_message",
+  "commit_title",
+  "enabled_by",
+  "merge_method",
+  "pages",
+  "path",
+  "actions",
+  "administration",
+  "content_references",
+  "discussions",
+  "emails",
+  "environments",
+  "keys",
+  "members",
+  "organization_administration",
+  "organization_hooks",
+  "organization_packages",
+  "organization_plan",
+  "organization_projects",
+  "organization_secrets",
+  "organization_self_hosted_runners",
+  "organization_user_blocking",
+  "packages",
+  "repository_hooks",
+  "repository_projects",
+  "secret_scanning_alerts",
+  "secrets",
+  "security_events",
+  "security_scanning_alert",
+  "single_file",
+  "team_discussions",
+  "vulnerability_alerts",
+  "workflows",
+  "run_attempt",
+  "committer",
+  "message",
+  "prerelease",
+  "tag_name",
+  "target_commitish",
+  "repository",
+  "repository_id",
+  "head_commit",
+  "timestamp",
+  "tree_id",
+  "to",
+  "content_type",
+  "published_at",
+  "category",
+  "emoji",
+  "is_answerable",
+  "state_reason",
+  "affected_package_name",
+  "affected_range",
+  "external_identifier",
+  "external_reference",
+  "fixed_in",
+  "ghsa_id",
+  "severity",
+  "check_run_url",
+  "run_id",
+  "run_url",
+  "runner_group_id",
+  "runner_group_name",
+  "runner_id",
+  "runner_name",
+  "workflow_name",
+  "steps",
+  "installations_count",
+  "client_id",
+  "client_secret",
+  "webhook_secret",
+  "pem",
+  "after",
+  "before",
+  "answer_chosen_at",
+  "answer_chosen_by",
+  "answer_html_url",
+  "release",
+  "assets",
+  "assets_url",
+  "tarball_url",
+  "upload_url",
+  "zipball_url",
+  "app",
+  "environment",
+  "summary",
+  "actor",
+  "artifacts_url",
+  "cancel_url",
+  "check_suite_id",
+  "check_suite_node_id",
+  "check_suite_url",
+  "event",
+  "head_repository",
+  "jobs_url",
+  "logs_url",
+  "previous_attempt_url",
+  "referenced_workflows",
+  "rerun_url",
+  "run_number",
+  "run_started_at",
+  "triggering_actor",
+  "workflow_id",
+  "workflow_url",
+  "note",
+  "after_id",
+  "column_id",
+  "project_url",
+  "dismiss_reason",
+  "dismissed_at",
+  "dismisser",
+  "fix_reason",
+  "fixed_at",
+  "commit",
+  "workflow_job",
+  "action",
+  "temp_clone_token",
+  "subscribers_count",
+  "network_count",
+  "check_suite",
+  "deployment",
+  "task",
+  "original_environment",
+  "transient_environment",
+  "production_environment",
+  "payload",
+  "workflow_run",
+  "discussion",
+  "comment",
+  "child_comment_count",
+  "discussion_id",
+  "parent_id",
+  "column_url",
+  "commit_id",
+  "pull_request_url",
+  "browser_download_url",
+  "download_count",
+  "uploader",
+  "discussion_url",
+  "alert",
+  "manifest",
+  "installation_command",
+  "version",
+  "admin_enforced",
+  "authorized_actor_names",
+  "authorized_actors_only",
+  "authorized_dismissal_actors_only",
+  "linear_history_requirement_enforcement_level",
+  "required_status_checks",
+  "required_status_checks_enforcement_level",
+  "check_run",
+  "details_url",
+  "external_id",
+  "actions_meta",
+  "check_runs_url",
+  "latest_check_runs_count",
+  "rerequestable",
+  "runs_rerequestable",
+  "workflow",
+  "display_title",
+  "project_card",
+  "content_url",
+  "short_description",
+  "archived_at",
+  "reason",
+  "diff_hunk",
+  "in_reply_to_id",
+  "line",
+  "original_commit_id",
+  "original_line",
+  "original_position",
+  "original_start_line",
+  "position",
+  "pull_request_review_id",
+  "side",
+  "start_line",
+  "start_side",
+  "ref_type",
+  "target_url",
+  "new_repository",
+  "pusher",
+  "added",
+  "distinct",
+  "modified",
+  "removed",
+  "registry_package",
+  "ecosystem",
+  "namespace",
+  "package_type",
+  "package_version",
+  "body_html",
+  "docker_metadata",
+  "package_files",
+  "download_url",
+  "md5",
+  "sha1",
+  "sha256",
+  "package_url",
+  "rubygems_metadata",
+  "target_oid",
+  "registry",
+  "dismiss_comment"
+]

languageservice/src/context-providers/needs.test.ts

@@ -111,7 +111,7 @@ jobs:
 on: push
 jobs:
   a:
-    uses: ./reusable-workflow-with-outputs.yaml
+    uses: ./.github/workflows/reusable-workflow-with-outputs.yaml
 
   b:
     needs: [a]

languageservice/src/hover.reusable-workflow.test.ts

@@ -14,7 +14,7 @@ on: push
 
 jobs:
   build:
-    uses: ./reusable-workflow-with-inputs.yaml
+    uses: ./.github/workflows/reusable-workflow-with-inputs.yaml
     with:
       us|ername:
 `;
@@ -31,7 +31,7 @@ on: push
 
 jobs:
   build:
-    uses: ./reusable-workflow-with-inputs-no-description.yaml
+    uses: ./.github/workflows/reusable-workflow-with-inputs-no-description.yaml
     with:
       us|ername:
 `;
@@ -48,7 +48,7 @@ on: push
 
 jobs:
   build:
-    uses: ./reusable-workflow-with-outputs.yaml
+    uses: ./.github/workflows/reusable-workflow-with-outputs.yaml
   echo_outputs:
     runs-on: ubuntu-latest
     needs: build

languageservice/src/hover.test.ts

@@ -110,11 +110,8 @@ jobs:
 `;
     const result = await hover(...getPositionFromCursor(input));
     expect(result).not.toBeUndefined();
-    expect(result?.contents).toEqual(
+    // Cron description is now shown via diagnostics, not hover
-      "Runs at 0 and 30 minutes past the hour, at 00:00 and 12:00\n\n" +
+    expect(result?.contents).toEqual("");
-        "Actions schedules run at most every 5 minutes. " +
-        "[Learn more](https://docs.github.com/actions/using-workflows/workflow-syntax-for-github-actions#onschedule)"
-    );
   });
 
   it("on a cron mapping key", async () => {

languageservice/src/hover.ts

@@ -2,11 +2,9 @@ import {data, DescriptionDictionary, Parser} from "@actions/expressions";
 import {FunctionDefinition, FunctionInfo} from "@actions/expressions/funcs/info";
 import {Lexer} from "@actions/expressions/lexer";
 import {ErrorPolicy} from "@actions/workflow-parser/model/convert";
-import {getCronDescription} from "@actions/workflow-parser/model/converter/cron";
 import {splitAllowedContext} from "@actions/workflow-parser/templates/allowed-context";
-import {StringToken} from "@actions/workflow-parser/templates/tokens/string-token";
 import {TemplateToken} from "@actions/workflow-parser/templates/tokens/template-token";
-import {isBasicExpression, isString} from "@actions/workflow-parser/templates/tokens/type-guards";
+import {isBasicExpression} from "@actions/workflow-parser/templates/tokens/type-guards";
 import {File} from "@actions/workflow-parser/workflows/file";
 import {FileProvider} from "@actions/workflow-parser/workflows/file-provider";
 import {Position, TextDocument} from "vscode-languageserver-textdocument";
@@ -23,7 +21,7 @@ import {ExpressionPos, mapToExpressionPos} from "./expression-hover/expression-p
 import {HoverVisitor} from "./expression-hover/visitor";
 import {info} from "./log";
 import {isPotentiallyExpression} from "./utils/expression-detection";
-import {findToken, TokenResult} from "./utils/find-token";
+import {findToken} from "./utils/find-token";
 import {mapRange} from "./utils/range";
 import {fetchOrConvertWorkflowTemplate, fetchOrParseWorkflow} from "./utils/workflow-cache";
 
@@ -89,17 +87,6 @@ export async function hover(document: TextDocument, position: Position, config?:
 
   info(`Calculating hover for token with definition ${token.definition.key}`);
 
-  if (tokenResult.parent && isCronMappingValue(tokenResult)) {
-    const tokenValue = (token as StringToken).value;
-    const description = getCronDescription(tokenValue);
-    if (description) {
-      return {
-        contents: description,
-        range: mapRange(token.range)
-      } satisfies Hover;
-    }
-  }
-
   if (tokenResult.parent && isReusableWorkflowJobInput(tokenResult)) {
     let description = getReusableWorkflowInputDescription(workflowContext, tokenResult);
     description = appendContext(description, token.definitionInfo?.allowedContext);
@@ -156,15 +143,6 @@ async function getDescription(
   return description || defaultDescription;
 }
 
-function isCronMappingValue(tokenResult: TokenResult): boolean {
-  return (
-    tokenResult.parent?.definition?.key === "cron-mapping" &&
-    !!tokenResult.token &&
-    isString(tokenResult.token) &&
-    tokenResult.token.value !== "cron"
-  );
-}
-
 function expressionHover(
   exprPos: ExpressionPos,
   context: DescriptionDictionary,

languageservice/src/test-utils/test-file-provider.ts

@@ -5,9 +5,9 @@ export const testFileProvider: FileProvider = {
   // eslint-disable-next-line @typescript-eslint/require-await
   getFileContent: async ref => {
     switch (fileIdentifier(ref)) {
-      case "monalisa/octocat/workflow.yaml@main":
+      case "monalisa/octocat/.github/workflows/workflow.yaml@main":
         return {
-          name: "monalisa/octocat/workflow.yaml",
+          name: "monalisa/octocat/.github/workflows/workflow.yaml",
           content: `
 on: workflow_call
 jobs:
@@ -31,9 +31,9 @@ jobs:
 `
         };
 
-      case "./reusable-workflow.yaml":
+      case "./.github/workflows/reusable-workflow.yaml":
         return {
-          name: "reusable-workflow.yaml",
+          name: ".github/workflows/reusable-workflow.yaml",
           content: `
 on: workflow_call
 jobs:
@@ -44,9 +44,9 @@ jobs:
 `
         };
 
-      case "./reusable-workflow-with-inputs.yaml":
+      case "./.github/workflows/reusable-workflow-with-inputs.yaml":
         return {
-          name: "reusable-workflow-with-inputs.yaml",
+          name: ".github/workflows/reusable-workflow-with-inputs.yaml",
           content: `
 on:
   workflow_call:
@@ -76,9 +76,9 @@ jobs:
   `
         };
 
-      case "./reusable-workflow-with-inputs-no-description.yaml":
+      case "./.github/workflows/reusable-workflow-with-inputs-no-description.yaml":
         return {
-          name: "reusable-workflow-with-inputs.yaml",
+          name: ".github/workflows/reusable-workflow-with-inputs.yaml",
           content: `
 on:
   workflow_call:
@@ -95,9 +95,9 @@ jobs:
   `
         };
 
-      case "./reusable-workflow-with-outputs.yaml":
+      case "./.github/workflows/reusable-workflow-with-outputs.yaml":
         return {
-          name: "reusable-workflow-with-outputs.yaml",
+          name: ".github/workflows/reusable-workflow-with-outputs.yaml",
           content: `
 on:
   workflow_call:

languageservice/src/validate.expressions.test.ts

@@ -635,7 +635,7 @@ jobs:
         fail-fast: true
         matrix:
           node: [14, 16]
-      uses: ./reusable-workflow-with-inputs.yaml
+      uses: ./.github/workflows/reusable-workflow-with-inputs.yaml
       with:
         username: User-\${{ strategy.fail-fast }}
   `;
@@ -654,7 +654,7 @@ jobs:
       strategy:
         matrix:
           node: [14, 16]
-      uses: ./reusable-workflow-with-inputs.yaml
+      uses: ./.github/workflows/reusable-workflow-with-inputs.yaml
       with:
         username: \${{ matrix.node }}
   `;

languageservice/src/validate.test.ts

@@ -181,7 +181,7 @@ jobs:
 
     expect(result.length).toBe(1);
     expect(result[0]).toEqual({
-      message: "Invalid cron string",
+      message: "Invalid cron expression. Expected format: '* * * * *' (minute hour day month weekday)",
       range: {
         end: {
           character: 21,
@@ -195,6 +195,96 @@ jobs:
     } as Diagnostic);
   });
 
+  it("cron with interval less than 5 minutes shows warning", async () => {
+    const result = await validate(
+      createDocument(
+        "wf.yaml",
+        `on:
+  schedule:
+    - cron: '*/1 * * * *'
+jobs:
+  build:
+    runs-on: ubuntu-latest`
+      ),
+      {valueProviderConfig: defaultValueProviders}
+    );
+
+    expect(result.length).toBe(1);
+    expect(result[0]).toEqual({
+      message:
+        'Actions schedules run at most every 5 minutes. "*/1 * * * *" (runs every minute) will not run as frequently as specified.',
+      severity: DiagnosticSeverity.Warning,
+      code: "on-schedule",
+      codeDescription: {
+        href: "https://docs.github.com/actions/using-workflows/workflow-syntax-for-github-actions#onschedule"
+      },
+      range: {
+        end: {
+          character: 25,
+          line: 2
+        },
+        start: {
+          character: 12,
+          line: 2
+        }
+      }
+    } as Diagnostic);
+  });
+
+  it("cron with interval of 5 minutes or more shows info", async () => {
+    const result = await validate(
+      createDocument(
+        "wf.yaml",
+        `on:
+  schedule:
+    - cron: '*/5 * * * *'
+jobs:
+  build:
+    runs-on: ubuntu-latest`
+      ),
+      {valueProviderConfig: defaultValueProviders}
+    );
+
+    expect(result.length).toBe(1);
+    expect(result[0]).toEqual({
+      message: "Runs every 5 minutes",
+      severity: DiagnosticSeverity.Information,
+      code: "on-schedule",
+      codeDescription: {
+        href: "https://docs.github.com/actions/using-workflows/workflow-syntax-for-github-actions#onschedule"
+      },
+      range: {
+        end: {
+          character: 25,
+          line: 2
+        },
+        start: {
+          character: 12,
+          line: 2
+        }
+      }
+    } as Diagnostic);
+  });
+
+  it("cron with comma-separated minutes less than 5 apart shows warning", async () => {
+    const result = await validate(
+      createDocument(
+        "wf.yaml",
+        `on:
+  schedule:
+    - cron: '0,2 * * * *'
+jobs:
+  build:
+    runs-on: ubuntu-latest`
+      ),
+      {valueProviderConfig: defaultValueProviders}
+    );
+
+    expect(result.length).toBe(1);
+    expect(result[0]?.severity).toBe(DiagnosticSeverity.Warning);
+    expect(result[0]?.message).toContain("Actions schedules run at most every 5 minutes.");
+  });
+
   it("invalid YAML", async () => {
     // This YAML has some mismatched single-quotes, which causes the string to be terminated early
     // within the fromJSON() expression.

languageservice/src/validate.ts

@@ -2,6 +2,7 @@ import {Lexer, Parser, data} from "@actions/expressions";
 import {Expr, FunctionCall, Literal, Logical} from "@actions/expressions/ast";
 import {ParseWorkflowResult, WorkflowTemplate, isBasicExpression, isString} from "@actions/workflow-parser";
 import {ErrorPolicy} from "@actions/workflow-parser/model/convert";
+import {getCronDescription, hasCronIntervalLessThan5Minutes} from "@actions/workflow-parser/model/converter/cron";
 import {ensureStatusFunction} from "@actions/workflow-parser/model/converter/if-condition";
 import {splitAllowedContext} from "@actions/workflow-parser/templates/allowed-context";
 import {BasicExpressionToken} from "@actions/workflow-parser/templates/tokens/basic-expression-token";
@@ -27,6 +28,9 @@ import {validateAction} from "./validate-action";
 import {ValueProviderConfig, ValueProviderKind} from "./value-providers/config";
 import {defaultValueProviders} from "./value-providers/default";
 
+const CRON_SCHEDULE_DOCS_URL =
+  "https://docs.github.com/actions/using-workflows/workflow-syntax-for-github-actions#onschedule";
+
 export type ValidationConfig = {
   valueProviderConfig?: ValueProviderConfig;
   contextProviderConfig?: ContextProviderConfig;
@@ -143,11 +147,34 @@ async function additionalValidations(
       }
     }
 
+    // Validate step uses field format
+    if (isString(token) && token.range && validationDefinition?.key === "step-uses") {
+      validateStepUsesFormat(diagnostics, token);
+    }
+
+    // Validate action metadata (inputs, required fields) for regular steps
     if (token.definition?.key === "regular-step" && token.range) {
       const context = getProviderContext(documentUri, template, root, token.range);
       await validateAction(diagnostics, token, context.step, config);
     }
 
+    // Validate job-level reusable workflow uses field format
+    if (
+      isString(token) &&
+      token.range &&
+      key &&
+      isString(key) &&
+      key.value === "uses" &&
+      parent?.definition?.key === "workflow-job"
+    ) {
+      validateWorkflowUsesFormat(diagnostics, token);
+    }
+
+    // Validate cron expressions - warn if interval is less than 5 minutes
+    if (isString(token) && token.range && validationDefinition?.key === "cron-pattern") {
+      validateCronExpression(diagnostics, token);
+    }
+
     // Allowed values coming from the schema have already been validated. Only check if
     // a value provider is defined for a token and if it is, validate the values match.
     if (token.range && validationDefinition) {
@@ -198,6 +225,357 @@ function invalidValue(diagnostics: Diagnostic[], token: StringToken, kind: Value
   }
 }
 
+/**
+ * Validates cron expressions and provides diagnostics for valid cron schedules.
+ * Shows a warning if the interval is less than 5 minutes (since GitHub Actions
+ * schedules run at most every 5 minutes), otherwise shows an info message.
+ */
+function validateCronExpression(diagnostics: Diagnostic[], token: StringToken): void {
+  const cronValue = token.value;
+
+  // Ensure we have a range for diagnostics
+  if (!token.range) {
+    return;
+  }
+
+  // Only check valid cron expressions - invalid ones are already caught by the parser
+  const description = getCronDescription(cronValue);
+  if (!description) {
+    return;
+  }
+
+  // Check if the cron specifies an interval less than 5 minutes
+  if (hasCronIntervalLessThan5Minutes(cronValue)) {
+    diagnostics.push({
+      message: `Actions schedules run at most every 5 minutes. "${cronValue}" (${description.toLowerCase()}) will not run as frequently as specified.`,
+      range: mapRange(token.range),
+      severity: DiagnosticSeverity.Warning,
+      code: "on-schedule",
+      codeDescription: {
+        href: CRON_SCHEDULE_DOCS_URL
+      }
+    });
+  } else {
+    // Show info message for valid cron expressions
+    diagnostics.push({
+      message: description,
+      range: mapRange(token.range),
+      severity: DiagnosticSeverity.Information,
+      code: "on-schedule",
+      codeDescription: {
+        href: CRON_SCHEDULE_DOCS_URL
+      }
+    });
+  }
+}
+
+/**
+ * Validates the format of a step's `uses` field.
+ *
+ * Valid formats:
+ * - docker://image:tag
+ * - ./local/path
+ * - .\local\path (Windows)
+ * - {owner}/{repo}@{ref}
+ * - {owner}/{repo}/{path}@{ref}
+ */
+function validateStepUsesFormat(diagnostics: Diagnostic[], token: StringToken): void {
+  const uses = token.value;
+
+  // Empty uses value
+  if (!uses) {
+    diagnostics.push({
+      message: "`uses' value in action cannot be blank",
+      severity: DiagnosticSeverity.Error,
+      range: mapRange(token.range),
+      code: "invalid-uses-format"
+    });
+    return;
+  }
+
+  // Docker image reference - always valid format
+  if (uses.startsWith("docker://")) {
+    return;
+  }
+
+  // Local action path - always valid format
+  if (uses.startsWith("./") || uses.startsWith(".\\")) {
+    return;
+  }
+
+  // Remote action: must be {owner}/{repo}[/path]@{ref}
+  const atSegments = uses.split("@");
+
+  // Must have exactly one @
+  if (atSegments.length !== 2) {
+    addStepUsesFormatError(diagnostics, token);
+    return;
+  }
+
+  const [repoPath, gitRef] = atSegments;
+
+  // Ref cannot be empty
+  if (!gitRef) {
+    addStepUsesFormatError(diagnostics, token);
+    return;
+  }
+
+  // Split by / or \ to get path segments
+  const pathSegments = repoPath.split(/[\\/]/);
+
+  // Must have at least owner and repo (both non-empty)
+  if (pathSegments.length < 2 || !pathSegments[0] || !pathSegments[1]) {
+    addStepUsesFormatError(diagnostics, token);
+    return;
+  }
+
+  // Check if this is a reusable workflow reference (should be at job level, not step)
+  // Path would be like: owner/repo/.github/workflows/file.yml
+  if (pathSegments.length >= 4 && pathSegments[2] === ".github" && pathSegments[3] === "workflows") {
+    diagnostics.push({
+      message: "Reusable workflows should be referenced at the top-level `jobs.<job_id>.uses` key, not within steps",
+      severity: DiagnosticSeverity.Error,
+      range: mapRange(token.range),
+      code: "invalid-uses-format"
+    });
+    return;
+  }
+}
+
+function addStepUsesFormatError(diagnostics: Diagnostic[], token: StringToken): void {
+  diagnostics.push({
+    message: `Expected format {owner}/{repo}[/path]@{ref}. Actual '${token.value}'`,
+    severity: DiagnosticSeverity.Error,
+    range: mapRange(token.range),
+    code: "invalid-uses-format"
+  });
+}
+
+/**
+ * Validates the format of a job's `uses` field (reusable workflow reference).
+ *
+ * Valid formats:
+ * - {owner}/{repo}/.github/workflows/{filename}.yml@{ref}
+ * - {owner}/{repo}/.github/workflows/{filename}.yaml@{ref}
+ * - {owner}/{repo}/.github/workflows-lab/{filename}.yml@{ref}
+ * - {owner}/{repo}/.github/workflows-lab/{filename}.yaml@{ref}
+ * - ./.github/workflows/{filename}.yml
+ * - ./.github/workflows/{filename}.yaml
+ * - ./.github/workflows-lab/{filename}.yml
+ * - ./.github/workflows-lab/{filename}.yaml
+ */
+function validateWorkflowUsesFormat(diagnostics: Diagnostic[], token: StringToken): void {
+  const uses = token.value;
+
+  // Local workflow reference
+  if (uses.startsWith("./.github/workflows/") || uses.startsWith("./.github/workflows-lab/")) {
+    // Cannot have @ version for local workflows
+    if (uses.includes("@")) {
+      addWorkflowUsesFormatError(diagnostics, token, "cannot specify version when calling local workflows");
+      return;
+    }
+
+    // Must have .yml or .yaml extension
+    if (!uses.endsWith(".yml") && !uses.endsWith(".yaml")) {
+      addWorkflowUsesFormatError(
+        diagnostics,
+        token,
+        "workflow file should have either a '.yml' or '.yaml' file extension"
+      );
+      return;
+    }
+
+    // Must be at top level of .github/workflows/ or .github/workflows-lab/ (no subdirectories)
+    const pathParts = uses.split("/");
+    if (pathParts.length !== 4) {
+      // Expected: ".", ".github", "workflows" or "workflows-lab", "filename.yml"
+      addWorkflowUsesFormatError(
+        diagnostics,
+        token,
+        "workflows must be defined at the top level of the .github/workflows/ directory"
+      );
+      return;
+    }
+
+    // Filename cannot be just the extension
+    const filename = pathParts[3];
+    if (filename === ".yml" || filename === ".yaml") {
+      addWorkflowUsesFormatError(diagnostics, token, "invalid workflow file name");
+      return;
+    }
+
+    return;
+  }
+
+  // Malformed local workflow reference (starts with ./ but not in .github/workflows)
+  if (uses.startsWith("./")) {
+    addWorkflowUsesFormatError(diagnostics, token, "local workflow references must be rooted in '.github/workflows'");
+    return;
+  }
+
+  // Remote workflow reference: must have @ for version
+  const atSegments = uses.split("@");
+  if (atSegments.length === 1) {
+    addWorkflowUsesFormatError(diagnostics, token, "no version specified");
+    return;
+  }
+  if (atSegments.length > 2) {
+    addWorkflowUsesFormatError(diagnostics, token, "too many '@' in workflow reference");
+    return;
+  }
+
+  const [pathPart, version] = atSegments;
+
+  // Version cannot be empty
+  if (!version) {
+    addWorkflowUsesFormatError(diagnostics, token, "no version specified");
+    return;
+  }
+
+  // Must contain .github/workflows or .github/workflows-lab path
+  const workflowsMatch = pathPart.match(/\.github\/workflows(-lab)?\//);
+  if (!workflowsMatch || workflowsMatch.index === undefined) {
+    addWorkflowUsesFormatError(diagnostics, token, "references to workflows must be rooted in '.github/workflows'");
+    return;
+  }
+
+  // Split to get owner/repo and path
+  const pathIdx = workflowsMatch.index;
+  const nwoPart = pathPart.substring(0, pathIdx);
+  const workflowPath = pathPart.substring(pathIdx);
+
+  // Validate NWO part: must be owner/repo/
+  const nwoSegments = nwoPart.split("/").filter(s => s.length > 0);
+  if (nwoSegments.length !== 2) {
+    addWorkflowUsesFormatError(
+      diagnostics,
+      token,
+      "references to workflows must be prefixed with format 'owner/repository/' or './' for local workflows"
+    );
+    return;
+  }
+
+  // Validate owner and repo names
+  const [owner, repo] = nwoSegments;
+  const nwoError = validateNWO(owner, repo);
+  if (nwoError) {
+    addWorkflowUsesFormatError(diagnostics, token, nwoError);
+    return;
+  }
+
+  // Validate ref/version format
+  const refError = validateRefName(version);
+  if (refError) {
+    addWorkflowUsesFormatError(diagnostics, token, refError);
+    return;
+  }
+
+  // Validate workflow path is at top level
+  const workflowPathParts = workflowPath.split("/");
+  if (workflowPathParts.length !== 3) {
+    // Expected: ".github", "workflows" or "workflows-lab", "filename.yml"
+    addWorkflowUsesFormatError(
+      diagnostics,
+      token,
+      "workflows must be defined at the top level of the .github/workflows/ directory"
+    );
+    return;
+  }
+
+  // Must have .yml or .yaml extension
+  const filename = workflowPathParts[2];
+  if (!filename.endsWith(".yml") && !filename.endsWith(".yaml")) {
+    addWorkflowUsesFormatError(
+      diagnostics,
+      token,
+      "workflow file should have either a '.yml' or '.yaml' file extension"
+    );
+    return;
+  }
+
+  // Filename cannot be just the extension
+  if (filename === ".yml" || filename === ".yaml") {
+    addWorkflowUsesFormatError(diagnostics, token, "invalid workflow file name");
+    return;
+  }
+}
+
+function addWorkflowUsesFormatError(diagnostics: Diagnostic[], token: StringToken, reason: string): void {
+  diagnostics.push({
+    message: `Invalid workflow reference '${token.value}': ${reason}`,
+    severity: DiagnosticSeverity.Error,
+    range: mapRange(token.range),
+    code: "invalid-workflow-uses-format"
+  });
+}
+
+/**
+ * Validates the git ref/version format.
+ * Based on Launch's ValidateRefName function.
+ */
+function validateRefName(refname: string): string | undefined {
+  if (refname.length === 0) {
+    return "no version specified";
+  }
+
+  // Cannot be the single character '@'
+  if (refname === "@") {
+    return "version cannot be the single character '@'";
+  }
+
+  // Cannot have certain invalid characters or sequences
+  const invalidSequences = ["?", "*", "[", "]", "\\", "~", "^", ":", "@{", "..", "//"];
+  for (const seq of invalidSequences) {
+    if (refname.includes(seq)) {
+      return `invalid character '${seq}' in version`;
+    }
+  }
+
+  // Cannot begin or end with a slash '/' or a dot '.'
+  if (refname.startsWith("/") || refname.endsWith("/") || refname.startsWith(".") || refname.endsWith(".")) {
+    return "version cannot begin or end with a slash '/' or a dot '.'";
+  }
+
+  // No slash-separated component can begin with a dot '.' or end with the sequence '.lock'
+  const components = refname.split("/");
+  for (const component of components) {
+    if (component.startsWith(".") || component.endsWith(".lock")) {
+      return `invalid version: ${refname}`;
+    }
+  }
+
+  // No ASCII control characters or whitespace
+  // eslint-disable-next-line no-control-regex
+  if (/[\x00-\x1f\x7f]/.test(refname)) {
+    return "version cannot have ASCII control characters";
+  }
+
+  if (/\s/.test(refname)) {
+    return "version cannot have whitespace";
+  }
+
+  return undefined;
+}
+
+/**
+ * Validates owner and repository names.
+ * Based on Launch's ValidateNWO function.
+ */
+function validateNWO(owner: string, repo: string): string | undefined {
+  // Owner name: can have word chars, dots, and hyphens
+  // \w in JS regex is [a-zA-Z0-9_]
+  if (!/^[\w.-]+$/.test(owner)) {
+    return "owner name must be a valid repository owner name";
+  }
+
+  // Repository name: can have word chars, dots, and hyphens
+  if (!/^[\w.-]+$/.test(repo)) {
+    return "repository name is invalid";
+  }
+
+  return undefined;
+}
+
 function getProviderContext(
   documentUri: URI,
   template: WorkflowTemplate,

languageservice/src/validate.uses-format.test.ts

@@ -0,0 +1,894 @@
+import {DiagnosticSeverity} from "vscode-languageserver-types";
+import {validate} from "./validate";
+import {createDocument} from "./test-utils/document";
+import {clearCache} from "./utils/workflow-cache";
+
+beforeEach(() => {
+  clearCache();
+});
+
+describe("validate uses format", () => {
+  describe("valid formats", () => {
+    it("standard org/repo@ref", async () => {
+      const input = `on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([]);
+    });
+
+    it("org/repo with path @ref", async () => {
+      const input = `on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/aws/ec2@main
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([]);
+    });
+
+    it("org/repo with deep path @ref", async () => {
+      const input = `on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/aws/nested/deep/path@v1
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([]);
+    });
+
+    it("docker image", async () => {
+      const input = `on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: docker://alpine:3.8
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([]);
+    });
+
+    it("docker image with registry", async () => {
+      const input = `on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: docker://gcr.io/my-project/my-image:latest
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([]);
+    });
+
+    it("local path with ./", async () => {
+      const input = `on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: ./my-action
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([]);
+    });
+
+    it("local path with ./ and subdirectories", async () => {
+      const input = `on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: ./.github/actions/my-action
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([]);
+    });
+
+    it("local path with .\\ (Windows)", async () => {
+      const input = `on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: .\\my-action
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([]);
+    });
+
+    it("SHA ref", async () => {
+      const input = `on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([]);
+    });
+
+    it("branch ref", async () => {
+      const input = `on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: owner/repo@feature/my-branch
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([]);
+    });
+  });
+
+  describe("invalid formats", () => {
+    it("missing @ref", async () => {
+      const input = `on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([
+        {
+          message: "Expected format {owner}/{repo}[/path]@{ref}. Actual 'actions/checkout'",
+          severity: DiagnosticSeverity.Error,
+          range: {
+            start: {line: 5, character: 12},
+            end: {line: 5, character: 28}
+          },
+          code: "invalid-uses-format"
+        }
+      ]);
+    });
+
+    it("empty ref", async () => {
+      const input = `on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([
+        {
+          message: "Expected format {owner}/{repo}[/path]@{ref}. Actual 'actions/checkout@'",
+          severity: DiagnosticSeverity.Error,
+          range: {
+            start: {line: 5, character: 12},
+            end: {line: 5, character: 29}
+          },
+          code: "invalid-uses-format"
+        }
+      ]);
+    });
+
+    it("missing org/owner", async () => {
+      const input = `on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: checkout@v4
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([
+        {
+          message: "Expected format {owner}/{repo}[/path]@{ref}. Actual 'checkout@v4'",
+          severity: DiagnosticSeverity.Error,
+          range: {
+            start: {line: 5, character: 12},
+            end: {line: 5, character: 23}
+          },
+          code: "invalid-uses-format"
+        }
+      ]);
+    });
+
+    it("empty owner", async () => {
+      const input = `on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: /repo@v4
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([
+        {
+          message: "Expected format {owner}/{repo}[/path]@{ref}. Actual '/repo@v4'",
+          severity: DiagnosticSeverity.Error,
+          range: {
+            start: {line: 5, character: 12},
+            end: {line: 5, character: 20}
+          },
+          code: "invalid-uses-format"
+        }
+      ]);
+    });
+
+    it("empty repo", async () => {
+      const input = `on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: owner/@v4
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([
+        {
+          message: "Expected format {owner}/{repo}[/path]@{ref}. Actual 'owner/@v4'",
+          severity: DiagnosticSeverity.Error,
+          range: {
+            start: {line: 5, character: 12},
+            end: {line: 5, character: 21}
+          },
+          code: "invalid-uses-format"
+        }
+      ]);
+    });
+
+    it("multiple @ symbols", async () => {
+      const input = `on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4@extra
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([
+        {
+          message: "Expected format {owner}/{repo}[/path]@{ref}. Actual 'actions/checkout@v4@extra'",
+          severity: DiagnosticSeverity.Error,
+          range: {
+            start: {line: 5, character: 12},
+            end: {line: 5, character: 37}
+          },
+          code: "invalid-uses-format"
+        }
+      ]);
+    });
+
+    it("just a name with no slash", async () => {
+      const input = `on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: checkout
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([
+        {
+          message: "Expected format {owner}/{repo}[/path]@{ref}. Actual 'checkout'",
+          severity: DiagnosticSeverity.Error,
+          range: {
+            start: {line: 5, character: 12},
+            end: {line: 5, character: 20}
+          },
+          code: "invalid-uses-format"
+        }
+      ]);
+    });
+
+    it("empty uses value", async () => {
+      const input = `on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: ""
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toContainEqual({
+        message: "`uses' value in action cannot be blank",
+        severity: DiagnosticSeverity.Error,
+        range: {
+          start: {line: 5, character: 12},
+          end: {line: 5, character: 14}
+        },
+        code: "invalid-uses-format"
+      });
+    });
+
+    it("reusable workflow in step", async () => {
+      const input = `on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: owner/repo/.github/workflows/test.yml@main
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([
+        {
+          message:
+            "Reusable workflows should be referenced at the top-level `jobs.<job_id>.uses` key, not within steps",
+          severity: DiagnosticSeverity.Error,
+          range: {
+            start: {line: 5, character: 12},
+            end: {line: 5, character: 54}
+          },
+          code: "invalid-uses-format"
+        }
+      ]);
+    });
+  });
+});
+
+describe("workflow uses format validation", () => {
+  beforeEach(() => {
+    clearCache();
+  });
+
+  describe("valid formats", () => {
+    it("local workflow path", async () => {
+      const input = `on: push
+jobs:
+  test:
+    uses: ./.github/workflows/test.yml
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([]);
+    });
+
+    it("local workflow path with yaml extension", async () => {
+      const input = `on: push
+jobs:
+  test:
+    uses: ./.github/workflows/test.yaml
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([]);
+    });
+
+    it("remote workflow with version", async () => {
+      const input = `on: push
+jobs:
+  test:
+    uses: owner/repo/.github/workflows/test.yml@v1
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([]);
+    });
+
+    it("remote workflow with sha ref", async () => {
+      const input = `on: push
+jobs:
+  test:
+    uses: owner/repo/.github/workflows/test.yml@abc123
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([]);
+    });
+
+    it("remote workflow with branch ref", async () => {
+      const input = `on: push
+jobs:
+  test:
+    uses: owner/repo/.github/workflows/test.yml@main
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([]);
+    });
+
+    it("remote workflow with yaml extension", async () => {
+      const input = `on: push
+jobs:
+  test:
+    uses: owner/repo/.github/workflows/test.yaml@v1
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([]);
+    });
+
+    it("local workflows-lab path", async () => {
+      const input = `on: push
+jobs:
+  test:
+    uses: ./.github/workflows-lab/test.yml
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([]);
+    });
+
+    it("local workflows-lab path with yaml extension", async () => {
+      const input = `on: push
+jobs:
+  test:
+    uses: ./.github/workflows-lab/test.yaml
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([]);
+    });
+
+    it("remote workflows-lab with version", async () => {
+      const input = `on: push
+jobs:
+  test:
+    uses: owner/repo/.github/workflows-lab/test.yml@v1
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([]);
+    });
+  });
+
+  describe("invalid formats", () => {
+    it("remote workflow missing version", async () => {
+      const input = `on: push
+jobs:
+  test:
+    uses: owner/repo/.github/workflows/test.yml
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([
+        {
+          message: "Invalid workflow reference 'owner/repo/.github/workflows/test.yml': no version specified",
+          severity: DiagnosticSeverity.Error,
+          range: {
+            start: {line: 3, character: 10},
+            end: {line: 3, character: 47}
+          },
+          code: "invalid-workflow-uses-format"
+        }
+      ]);
+    });
+
+    it("local workflow with version", async () => {
+      const input = `on: push
+jobs:
+  test:
+    uses: ./.github/workflows/test.yml@v1
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([
+        {
+          message:
+            "Invalid workflow reference './.github/workflows/test.yml@v1': cannot specify version when calling local workflows",
+          severity: DiagnosticSeverity.Error,
+          range: {
+            start: {line: 3, character: 10},
+            end: {line: 3, character: 41}
+          },
+          code: "invalid-workflow-uses-format"
+        }
+      ]);
+    });
+
+    it("malformed local path not in .github/workflows", async () => {
+      const input = `on: push
+jobs:
+  test:
+    uses: ./foo/bar.yml
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([
+        {
+          message:
+            "Invalid workflow reference './foo/bar.yml': local workflow references must be rooted in '.github/workflows'",
+          severity: DiagnosticSeverity.Error,
+          range: {
+            start: {line: 3, character: 10},
+            end: {line: 3, character: 23}
+          },
+          code: "invalid-workflow-uses-format"
+        }
+      ]);
+    });
+
+    it("missing .github/workflows path", async () => {
+      const input = `on: push
+jobs:
+  test:
+    uses: owner/repo/test.yml@v1
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([
+        {
+          message:
+            "Invalid workflow reference 'owner/repo/test.yml@v1': references to workflows must be rooted in '.github/workflows'",
+          severity: DiagnosticSeverity.Error,
+          range: {
+            start: {line: 3, character: 10},
+            end: {line: 3, character: 32}
+          },
+          code: "invalid-workflow-uses-format"
+        }
+      ]);
+    });
+
+    it("invalid file extension", async () => {
+      const input = `on: push
+jobs:
+  test:
+    uses: owner/repo/.github/workflows/test.txt@v1
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([
+        {
+          message:
+            "Invalid workflow reference 'owner/repo/.github/workflows/test.txt@v1': workflow file should have either a '.yml' or '.yaml' file extension",
+          severity: DiagnosticSeverity.Error,
+          range: {
+            start: {line: 3, character: 10},
+            end: {line: 3, character: 50}
+          },
+          code: "invalid-workflow-uses-format"
+        }
+      ]);
+    });
+
+    it("no extension", async () => {
+      const input = `on: push
+jobs:
+  test:
+    uses: owner/repo/.github/workflows/test@v1
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([
+        {
+          message:
+            "Invalid workflow reference 'owner/repo/.github/workflows/test@v1': workflow file should have either a '.yml' or '.yaml' file extension",
+          severity: DiagnosticSeverity.Error,
+          range: {
+            start: {line: 3, character: 10},
+            end: {line: 3, character: 46}
+          },
+          code: "invalid-workflow-uses-format"
+        }
+      ]);
+    });
+
+    it("just a ref", async () => {
+      const input = `on: push
+jobs:
+  test:
+    uses: test.yml@v1
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([
+        {
+          message:
+            "Invalid workflow reference 'test.yml@v1': references to workflows must be rooted in '.github/workflows'",
+          severity: DiagnosticSeverity.Error,
+          range: {
+            start: {line: 3, character: 10},
+            end: {line: 3, character: 21}
+          },
+          code: "invalid-workflow-uses-format"
+        }
+      ]);
+    });
+
+    it("local without .github/workflows", async () => {
+      const input = `on: push
+jobs:
+  test:
+    uses: ./workflows/test.yml
+`;
+      const result = await validate(createDocument("wf.yaml", input));
+      expect(result).toEqual([
+        {
+          message:
+            "Invalid workflow reference './workflows/test.yml': local workflow references must be rooted in '.github/workflows'",
+          severity: DiagnosticSeverity.Error,
+          range: {
+            start: {line: 3, character: 10},
+            end: {line: 3, character: 30}
+          },
+          code: "invalid-workflow-uses-format"
+        }
+      ]);
+    });
+
+    describe("invalid ref/version format", () => {
+      it("empty version after @", async () => {
+        const input = `on: push
+jobs:
+  test:
+    uses: owner/repo/.github/workflows/test.yml@
+`;
+        const result = await validate(createDocument("wf.yaml", input));
+        expect(result).toEqual([
+          {
+            message: "Invalid workflow reference 'owner/repo/.github/workflows/test.yml@': no version specified",
+            severity: DiagnosticSeverity.Error,
+            range: {
+              start: {line: 3, character: 10},
+              end: {line: 3, character: 48}
+            },
+            code: "invalid-workflow-uses-format"
+          }
+        ]);
+      });
+
+      it("version with invalid character ?", async () => {
+        const input = `on: push
+jobs:
+  test:
+    uses: owner/repo/.github/workflows/test.yml@v1?
+`;
+        const result = await validate(createDocument("wf.yaml", input));
+        expect(result).toEqual([
+          {
+            message:
+              "Invalid workflow reference 'owner/repo/.github/workflows/test.yml@v1?': invalid character '?' in version",
+            severity: DiagnosticSeverity.Error,
+            range: {
+              start: {line: 3, character: 10},
+              end: {line: 3, character: 51}
+            },
+            code: "invalid-workflow-uses-format"
+          }
+        ]);
+      });
+
+      it("version with double dots", async () => {
+        const input = `on: push
+jobs:
+  test:
+    uses: owner/repo/.github/workflows/[email protected]
+`;
+        const result = await validate(createDocument("wf.yaml", input));
+        expect(result).toEqual([
+          {
+            message:
+              "Invalid workflow reference 'owner/repo/.github/workflows/[email protected]': invalid character '..' in version",
+            severity: DiagnosticSeverity.Error,
+            range: {
+              start: {line: 3, character: 10},
+              end: {line: 3, character: 54}
+            },
+            code: "invalid-workflow-uses-format"
+          }
+        ]);
+      });
+
+      it("version ending with dot", async () => {
+        const input = `on: push
+jobs:
+  test:
+    uses: owner/repo/.github/workflows/test.yml@v1.
+`;
+        const result = await validate(createDocument("wf.yaml", input));
+        expect(result).toEqual([
+          {
+            message:
+              "Invalid workflow reference 'owner/repo/.github/workflows/test.yml@v1.': version cannot begin or end with a slash '/' or a dot '.'",
+            severity: DiagnosticSeverity.Error,
+            range: {
+              start: {line: 3, character: 10},
+              end: {line: 3, character: 51}
+            },
+            code: "invalid-workflow-uses-format"
+          }
+        ]);
+      });
+
+      it("version starting with slash", async () => {
+        const input = `on: push
+jobs:
+  test:
+    uses: owner/repo/.github/workflows/test.yml@/v1
+`;
+        const result = await validate(createDocument("wf.yaml", input));
+        expect(result).toEqual([
+          {
+            message:
+              "Invalid workflow reference 'owner/repo/.github/workflows/test.yml@/v1': version cannot begin or end with a slash '/' or a dot '.'",
+            severity: DiagnosticSeverity.Error,
+            range: {
+              start: {line: 3, character: 10},
+              end: {line: 3, character: 51}
+            },
+            code: "invalid-workflow-uses-format"
+          }
+        ]);
+      });
+
+      it("version ending with .lock", async () => {
+        const input = `on: push
+jobs:
+  test:
+    uses: owner/repo/.github/workflows/test.yml@refs/heads/main.lock
+`;
+        const result = await validate(createDocument("wf.yaml", input));
+        expect(result).toEqual([
+          {
+            message:
+              "Invalid workflow reference 'owner/repo/.github/workflows/test.yml@refs/heads/main.lock': invalid version: refs/heads/main.lock",
+            severity: DiagnosticSeverity.Error,
+            range: {
+              start: {line: 3, character: 10},
+              end: {line: 3, character: 68}
+            },
+            code: "invalid-workflow-uses-format"
+          }
+        ]);
+      });
+
+      it("version with whitespace", async () => {
+        const input = `on: push
+jobs:
+  test:
+    uses: owner/repo/.github/workflows/test.yml@v1 && rm -rf
+`;
+        const result = await validate(createDocument("wf.yaml", input));
+        expect(result).toEqual([
+          {
+            message:
+              "Invalid workflow reference 'owner/repo/.github/workflows/test.yml@v1 && rm -rf': version cannot have whitespace",
+            severity: DiagnosticSeverity.Error,
+            range: {
+              start: {line: 3, character: 10},
+              end: {line: 3, character: 60}
+            },
+            code: "invalid-workflow-uses-format"
+          }
+        ]);
+      });
+
+      it("version with backslash", async () => {
+        const input = `on: push
+jobs:
+  test:
+    uses: owner/repo/.github/workflows/test.yml@v1\\1
+`;
+        const result = await validate(createDocument("wf.yaml", input));
+        expect(result).toEqual([
+          {
+            message:
+              "Invalid workflow reference 'owner/repo/.github/workflows/test.yml@v1\\1': invalid character '\\' in version",
+            severity: DiagnosticSeverity.Error,
+            range: {
+              start: {line: 3, character: 10},
+              end: {line: 3, character: 52}
+            },
+            code: "invalid-workflow-uses-format"
+          }
+        ]);
+      });
+    });
+
+    describe("invalid owner/repo names", () => {
+      it("owner with invalid characters", async () => {
+        const input = `on: push
+jobs:
+  test:
+    uses: owner*/repo/.github/workflows/test.yml@v1
+`;
+        const result = await validate(createDocument("wf.yaml", input));
+        expect(result).toEqual([
+          {
+            message:
+              "Invalid workflow reference 'owner*/repo/.github/workflows/test.yml@v1': owner name must be a valid repository owner name",
+            severity: DiagnosticSeverity.Error,
+            range: {
+              start: {line: 3, character: 10},
+              end: {line: 3, character: 51}
+            },
+            code: "invalid-workflow-uses-format"
+          }
+        ]);
+      });
+
+      it("repo with invalid characters", async () => {
+        const input = `on: push
+jobs:
+  test:
+    uses: owner/repo!name/.github/workflows/test.yml@v1
+`;
+        const result = await validate(createDocument("wf.yaml", input));
+        expect(result).toEqual([
+          {
+            message:
+              "Invalid workflow reference 'owner/repo!name/.github/workflows/test.yml@v1': repository name is invalid",
+            severity: DiagnosticSeverity.Error,
+            range: {
+              start: {line: 3, character: 10},
+              end: {line: 3, character: 55}
+            },
+            code: "invalid-workflow-uses-format"
+          }
+        ]);
+      });
+
+      it("owner with spaces", async () => {
+        const input = `on: push
+jobs:
+  test:
+    uses: owner name/repo/.github/workflows/test.yml@v1
+`;
+        const result = await validate(createDocument("wf.yaml", input));
+        expect(result).toEqual([
+          {
+            message:
+              "Invalid workflow reference 'owner name/repo/.github/workflows/test.yml@v1': owner name must be a valid repository owner name",
+            severity: DiagnosticSeverity.Error,
+            range: {
+              start: {line: 3, character: 10},
+              end: {line: 3, character: 55}
+            },
+            code: "invalid-workflow-uses-format"
+          }
+        ]);
+      });
+    });
+
+    describe("invalid workflow filename", () => {
+      it("filename is just .yml", async () => {
+        const input = `on: push
+jobs:
+  test:
+    uses: owner/repo/.github/workflows/.yml@v1
+`;
+        const result = await validate(createDocument("wf.yaml", input));
+        expect(result).toEqual([
+          {
+            message: "Invalid workflow reference 'owner/repo/.github/workflows/.yml@v1': invalid workflow file name",
+            severity: DiagnosticSeverity.Error,
+            range: {
+              start: {line: 3, character: 10},
+              end: {line: 3, character: 46}
+            },
+            code: "invalid-workflow-uses-format"
+          }
+        ]);
+      });
+
+      it("filename is just .yaml", async () => {
+        const input = `on: push
+jobs:
+  test:
+    uses: owner/repo/.github/workflows/.yaml@v1
+`;
+        const result = await validate(createDocument("wf.yaml", input));
+        expect(result).toEqual([
+          {
+            message: "Invalid workflow reference 'owner/repo/.github/workflows/.yaml@v1': invalid workflow file name",
+            severity: DiagnosticSeverity.Error,
+            range: {
+              start: {line: 3, character: 10},
+              end: {line: 3, character: 47}
+            },
+            code: "invalid-workflow-uses-format"
+          }
+        ]);
+      });
+
+      it("local workflow filename is just .yml", async () => {
+        const input = `on: push
+jobs:
+  test:
+    uses: ./.github/workflows/.yml
+`;
+        const result = await validate(createDocument("wf.yaml", input));
+        expect(result).toEqual([
+          {
+            message: "Invalid workflow reference './.github/workflows/.yml': invalid workflow file name",
+            severity: DiagnosticSeverity.Error,
+            range: {
+              start: {line: 3, character: 10},
+              end: {line: 3, character: 34}
+            },
+            code: "invalid-workflow-uses-format"
+          }
+        ]);
+      });
+    });
+  });
+});

languageservice/src/validate.workflow-references.test.ts

@@ -43,7 +43,7 @@ on: push
 
 jobs:
   build:
-    uses: monalisa/octocat/workflow.yaml@not-a-branch
+    uses: monalisa/octocat/.github/workflows/workflow.yaml@not-a-branch
 `;
     const result = await validate(createDocument("wf.yaml", input), {
       fileProvider: testFileProvider
@@ -58,7 +58,7 @@ jobs:
             line: 5
           },
           end: {
-            character: 53,
+            character: 71,
             line: 5
           }
         }
@@ -72,7 +72,7 @@ on: push
 
 jobs:
   build:
-    uses: monalisa/octocat/workflow.yaml@main
+    uses: monalisa/octocat/.github/workflows/workflow.yaml@main
 `;
     const result = await validate(createDocument("wf.yaml", input), {
       fileProvider: testFileProvider
@@ -87,7 +87,7 @@ on: push
 
 jobs:
   build:
-    uses: ./reusable-workflow.yaml
+    uses: ./.github/workflows/reusable-workflow.yaml
 `;
     const result = await validate(createDocument("wf.yaml", input), {
       fileProvider: testFileProvider
@@ -102,7 +102,7 @@ on: push
 
 jobs:
   build:
-    uses: ./reusable-workflow-with-inputs.yaml
+    uses: ./.github/workflows/reusable-workflow-with-inputs.yaml
     secrets:
       envPAT: pat
 `;
@@ -119,7 +119,7 @@ jobs:
             line: 5
           },
           end: {
-            character: 46,
+            character: 64,
             line: 5
           }
         }
@@ -133,7 +133,7 @@ on: push
 
 jobs:
   build:
-    uses: ./reusable-workflow-with-inputs.yaml
+    uses: ./.github/workflows/reusable-workflow-with-inputs.yaml
     with:
       username: monalisa
     secrets:

lerna.json

@@ -6,5 +6,5 @@
     "languageservice",
     "languageserver"
   ],
-  "version": "0.3.20"
+  "version": "0.3.23"
 }

package-lock.json

@@ -135,7 +135,7 @@
     },
     "expressions": {
       "name": "@actions/expressions",
-      "version": "0.3.20",
+      "version": "0.3.23",
       "license": "MIT",
       "devDependencies": {
         "@types/jest": "^29.0.3",
@@ -340,9 +340,9 @@
       }
     },
     "expressions/node_modules/js-yaml": {
-      "version": "4.1.0",
+      "version": "4.1.1",
-      "resolved": "https://registry.npmjs.org/js-yaml/-/js-yaml-4.1.0.tgz",
+      "resolved": "https://registry.npmjs.org/js-yaml/-/js-yaml-4.1.1.tgz",
-      "integrity": "sha512-wpxZs9NoxZaJESJGIZTyDEaYpl0FKSA+FB9aJiyemKhMwkxQg63h4T1KJgUGHpTqPDNRcmmYLugrRjJlBtWvRA==",
+      "integrity": "sha512-qQKT4zQxXl8lLwBtHMWwaTcGfFOZviOJet3Oy/xmGk2gZH677CJM9EvtfdSkgWcATZhj/55JZ0rmy3myCT5lsA==",
       "dev": true,
       "dependencies": {
         "argparse": "^2.0.1"
@@ -395,11 +395,11 @@
     },
     "languageserver": {
       "name": "@actions/languageserver",
-      "version": "0.3.20",
+      "version": "0.3.23",
       "license": "MIT",
       "dependencies": {
-        "@actions/languageservice": "^0.3.20",
+        "@actions/languageservice": "^0.3.23",
-        "@actions/workflow-parser": "^0.3.20",
+        "@actions/workflow-parser": "^0.3.23",
         "@octokit/rest": "^21.1.1",
         "@octokit/types": "^9.0.0",
         "vscode-languageserver": "^8.0.2",
@@ -921,11 +921,11 @@
     },
     "languageservice": {
       "name": "@actions/languageservice",
-      "version": "0.3.20",
+      "version": "0.3.23",
       "license": "MIT",
       "dependencies": {
-        "@actions/expressions": "^0.3.20",
+        "@actions/expressions": "^0.3.23",
-        "@actions/workflow-parser": "^0.3.20",
+        "@actions/workflow-parser": "^0.3.23",
         "vscode-languageserver-textdocument": "^1.0.7",
         "vscode-languageserver-types": "^3.17.2",
         "vscode-uri": "^3.0.8",
@@ -1136,9 +1136,9 @@
       }
     },
     "languageservice/node_modules/js-yaml": {
-      "version": "4.1.0",
+      "version": "4.1.1",
-      "resolved": "https://registry.npmjs.org/js-yaml/-/js-yaml-4.1.0.tgz",
+      "resolved": "https://registry.npmjs.org/js-yaml/-/js-yaml-4.1.1.tgz",
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@@ -1218,89 +1218,19 @@
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-      "version": "7.22.13",
+      "version": "7.27.1",
-      "resolved": "https://registry.npmjs.org/@babel/code-frame/-/code-frame-7.22.13.tgz",
+      "resolved": "https://registry.npmjs.org/@babel/code-frame/-/code-frame-7.27.1.tgz",
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       "dev": true,
       "dependencies": {
-        "@babel/highlight": "^7.22.13",
+        "@babel/helper-validator-identifier": "^7.27.1",
-        "chalk": "^2.4.2"
+        "js-tokens": "^4.0.0",
+        "picocolors": "^1.1.1"
       },
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         "node": ">=6.9.0"
       }
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-    "node_modules/@babel/code-frame/node_modules/ansi-styles": {
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-      "resolved": "https://registry.npmjs.org/ansi-styles/-/ansi-styles-3.2.1.tgz",
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-      "resolved": "https://registry.npmjs.org/chalk/-/chalk-2.4.2.tgz",
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-        "escape-string-regexp": "^1.0.5",
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-      "engines": {
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-      }
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-    "node_modules/@babel/code-frame/node_modules/has-flag": {
-      "version": "3.0.0",
-      "resolved": "https://registry.npmjs.org/has-flag/-/has-flag-3.0.0.tgz",
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-      "dev": true,
-      "engines": {
-        "node": ">=4"
-      }
-    },
-    "node_modules/@babel/code-frame/node_modules/supports-color": {
-      "version": "5.5.0",
-      "resolved": "https://registry.npmjs.org/supports-color/-/supports-color-5.5.0.tgz",
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-      "dev": true,
-      "dependencies": {
-        "has-flag": "^3.0.0"
-      },
-      "engines": {
-        "node": ">=4"
-      }
-    },
     "node_modules/@babel/compat-data": {
       "version": "7.20.1",
       "dev": true,
@@ -1483,18 +1413,18 @@
       }
     },
     "node_modules/@babel/helper-string-parser": {
-      "version": "7.22.5",
+      "version": "7.27.1",
-      "resolved": "https://registry.npmjs.org/@babel/helper-string-parser/-/helper-string-parser-7.22.5.tgz",
+      "resolved": "https://registry.npmjs.org/@babel/helper-string-parser/-/helper-string-parser-7.27.1.tgz",
-      "integrity": "sha512-mM4COjgZox8U+JcXQwPijIZLElkgEpO5rsERVDJTc2qfCDfERyob6k5WegS14SX18IIjv+XD+GrqNumY5JRCDw==",
+      "integrity": "sha512-qMlSxKbpRlAridDExk92nSobyDdpPijUq2DW6oDnUqd0iOGxmQjyqhMIihI9+zv4LPyZdRje2cavWPbCbWm3eA==",
       "dev": true,
       "engines": {
         "node": ">=6.9.0"
       }
     },
     "node_modules/@babel/helper-validator-identifier": {
-      "version": "7.22.20",
+      "version": "7.28.5",
-      "resolved": "https://registry.npmjs.org/@babel/helper-validator-identifier/-/helper-validator-identifier-7.22.20.tgz",
+      "resolved": "https://registry.npmjs.org/@babel/helper-validator-identifier/-/helper-validator-identifier-7.28.5.tgz",
-      "integrity": "sha512-Y4OZ+ytlatR8AI+8KZfKuL5urKp7qey08ha31L8b3BwewJAoJamTzyvxPR/5D+KkdJCGPq/+8TukHBlY10FX9A==",
+      "integrity": "sha512-qSs4ifwzKJSV39ucNjsvc6WVHs6b7S03sOh2OcHF9UHfVPqWWALUsNUVzhSBiItjRZoLHx7nIarVjqKVusUZ1Q==",
       "dev": true,
       "engines": {
         "node": ">=6.9.0"
@@ -1509,13 +1439,13 @@
       }
     },
     "node_modules/@babel/helpers": {
-      "version": "7.20.1",
+      "version": "7.28.4",
+      "resolved": "https://registry.npmjs.org/@babel/helpers/-/helpers-7.28.4.tgz",
+      "integrity": "sha512-HFN59MmQXGHVyYadKLVumYsA9dBFun/ldYxipEjzA4196jpLZd8UjEEBLkbEkvfYreDqJhZxYAWFPtrfhNpj4w==",
       "dev": true,
-      "license": "MIT",
       "dependencies": {
-        "@babel/template": "^7.18.10",
+        "@babel/template": "^7.27.2",
-        "@babel/traverse": "^7.20.1",
+        "@babel/types": "^7.28.4"
-        "@babel/types": "^7.20.0"
       },
       "engines": {
         "node": ">=6.9.0"
@@ -1600,10 +1530,13 @@
       }
     },
     "node_modules/@babel/parser": {
-      "version": "7.23.0",
+      "version": "7.28.5",
-      "resolved": "https://registry.npmjs.org/@babel/parser/-/parser-7.23.0.tgz",
+      "resolved": "https://registry.npmjs.org/@babel/parser/-/parser-7.28.5.tgz",
-      "integrity": "sha512-vvPKKdMemU85V9WE/l5wZEmImpCtLqbnTvqDS2U1fJ96KrxoW7KrXhNsNCblQlg8Ck4b85yxdTyelsMUgFUXiw==",
+      "integrity": "sha512-KKBU1VGYR7ORr3At5HAtUQ+TV3SzRCXmA/8OdDZiLDBIZxVyzXuztPjfLd3BV1PRAQGCMWWSHYhL0F8d5uHBDQ==",
       "dev": true,
+      "dependencies": {
+        "@babel/types": "^7.28.5"
+      },
       "bin": {
         "parser": "bin/babel-parser.js"
       },
@@ -1786,14 +1719,14 @@
       }
     },
     "node_modules/@babel/template": {
-      "version": "7.22.15",
+      "version": "7.27.2",
-      "resolved": "https://registry.npmjs.org/@babel/template/-/template-7.22.15.tgz",
+      "resolved": "https://registry.npmjs.org/@babel/template/-/template-7.27.2.tgz",
-      "integrity": "sha512-QPErUVm4uyJa60rkI73qneDacvdvzxshT3kksGqlGWYdOTIUOwJ7RDUL8sGqslY1uXWSL6xMFKEXDS3ox2uF0w==",
+      "integrity": "sha512-LPDZ85aEJyYSd18/DkjNh4/y1ntkE5KwUHWTiqgRxruuZL2F1yuHligVHLvcHY2vMHXttKFpJn6LwfI7cw7ODw==",
       "dev": true,
       "dependencies": {
-        "@babel/code-frame": "^7.22.13",
+        "@babel/code-frame": "^7.27.1",
-        "@babel/parser": "^7.22.15",
+        "@babel/parser": "^7.27.2",
-        "@babel/types": "^7.22.15"
+        "@babel/types": "^7.27.1"
       },
       "engines": {
         "node": ">=6.9.0"
@@ -1821,14 +1754,13 @@
       }
     },
     "node_modules/@babel/types": {
-      "version": "7.23.0",
+      "version": "7.28.5",
-      "resolved": "https://registry.npmjs.org/@babel/types/-/types-7.23.0.tgz",
+      "resolved": "https://registry.npmjs.org/@babel/types/-/types-7.28.5.tgz",
-      "integrity": "sha512-0oIyUfKoI3mSqMvsxBdclDwxXKXAUA8v/apZbc+iSyARYou1o8ZGDxbUYyLFoW2arqS2jDGqJuZvv1d/io1axg==",
+      "integrity": "sha512-qQ5m48eI/MFLQ5PxQj4PFaprjyCTLI37ElWMmNs0K8Lk3dVeOdNpB3ks8jc7yM5CDmVC73eMVk/trk3fgmrUpA==",
       "dev": true,
       "dependencies": {
-        "@babel/helper-string-parser": "^7.22.5",
+        "@babel/helper-string-parser": "^7.27.1",
-        "@babel/helper-validator-identifier": "^7.22.20",
+        "@babel/helper-validator-identifier": "^7.28.5"
-        "to-fast-properties": "^2.0.0"
       },
       "engines": {
         "node": ">=6.9.0"
@@ -4231,12 +4163,10 @@
       }
     },
     "node_modules/@typescript-eslint/eslint-plugin/node_modules/semver": {
-      "version": "7.3.8",
+      "version": "7.7.3",
+      "resolved": "https://registry.npmjs.org/semver/-/semver-7.7.3.tgz",
+      "integrity": "sha512-SdsKMrI9TdgjdweUSR9MweHA4EJ8YxHn8DFaDisvhVlUOe4BF1tLD7GAj0lIqWVl+dPb/rExr0Btby5loQm20Q==",
       "dev": true,
-      "license": "ISC",
-      "dependencies": {
-        "lru-cache": "^6.0.0"
-      },
       "bin": {
         "semver": "bin/semver.js"
       },
@@ -4361,12 +4291,10 @@
       }
     },
     "node_modules/@typescript-eslint/typescript-estree/node_modules/semver": {
-      "version": "7.3.8",
+      "version": "7.7.3",
+      "resolved": "https://registry.npmjs.org/semver/-/semver-7.7.3.tgz",
+      "integrity": "sha512-SdsKMrI9TdgjdweUSR9MweHA4EJ8YxHn8DFaDisvhVlUOe4BF1tLD7GAj0lIqWVl+dPb/rExr0Btby5loQm20Q==",
       "dev": true,
-      "license": "ISC",
-      "dependencies": {
-        "lru-cache": "^6.0.0"
-      },
       "bin": {
         "semver": "bin/semver.js"
       },
@@ -4402,12 +4330,10 @@
       }
     },
     "node_modules/@typescript-eslint/utils/node_modules/semver": {
-      "version": "7.3.8",
+      "version": "7.7.3",
+      "resolved": "https://registry.npmjs.org/semver/-/semver-7.7.3.tgz",
+      "integrity": "sha512-SdsKMrI9TdgjdweUSR9MweHA4EJ8YxHn8DFaDisvhVlUOe4BF1tLD7GAj0lIqWVl+dPb/rExr0Btby5loQm20Q==",
       "dev": true,
-      "license": "ISC",
-      "dependencies": {
-        "lru-cache": "^6.0.0"
-      },
       "bin": {
         "semver": "bin/semver.js"
       },
@@ -4877,9 +4803,10 @@
       }
     },
     "node_modules/brace-expansion": {
-      "version": "1.1.11",
+      "version": "1.1.12",
+      "resolved": "https://registry.npmjs.org/brace-expansion/-/brace-expansion-1.1.12.tgz",
+      "integrity": "sha512-9T9UjW3r0UW5c1Q7GTwllptXwhvYmEzFhzMfZ9H7FQWt+uZePjZPjBP/W1ZEyZ1twGWom5/56TF4lPcqjnDHcg==",
       "dev": true,
-      "license": "MIT",
       "dependencies": {
         "balanced-match": "^1.0.0",
         "concat-map": "0.0.1"
@@ -6265,12 +6192,10 @@
       }
     },
     "node_modules/eslint/node_modules/semver": {
-      "version": "7.3.8",
+      "version": "7.7.3",
+      "resolved": "https://registry.npmjs.org/semver/-/semver-7.7.3.tgz",
+      "integrity": "sha512-SdsKMrI9TdgjdweUSR9MweHA4EJ8YxHn8DFaDisvhVlUOe4BF1tLD7GAj0lIqWVl+dPb/rExr0Btby5loQm20Q==",
       "dev": true,
-      "license": "ISC",
-      "dependencies": {
-        "lru-cache": "^6.0.0"
-      },
       "bin": {
         "semver": "bin/semver.js"
       },
@@ -8392,12 +8317,10 @@
       }
     },
     "node_modules/jest-snapshot/node_modules/semver": {
-      "version": "7.3.8",
+      "version": "7.7.3",
+      "resolved": "https://registry.npmjs.org/semver/-/semver-7.7.3.tgz",
+      "integrity": "sha512-SdsKMrI9TdgjdweUSR9MweHA4EJ8YxHn8DFaDisvhVlUOe4BF1tLD7GAj0lIqWVl+dPb/rExr0Btby5loQm20Q==",
       "dev": true,
-      "license": "ISC",
-      "dependencies": {
-        "lru-cache": "^6.0.0"
-      },
       "bin": {
         "semver": "bin/semver.js"
       },
@@ -8510,9 +8433,10 @@
       "license": "MIT"
     },
     "node_modules/js-yaml": {
-      "version": "3.14.1",
+      "version": "3.14.2",
+      "resolved": "https://registry.npmjs.org/js-yaml/-/js-yaml-3.14.2.tgz",
+      "integrity": "sha512-PMSmkqxr106Xa156c2M265Z+FTrPl+oxd/rgOQy2tijQeK5TxQ43psO1ZCwhVOSdnn+RzkzlRz/eY4BgJBYVpg==",
       "dev": true,
-      "license": "MIT",
       "dependencies": {
         "argparse": "^1.0.7",
         "esprima": "^4.0.0"
@@ -9514,11 +9438,12 @@
       }
     },
     "node_modules/micromatch": {
-      "version": "4.0.5",
+      "version": "4.0.8",
+      "resolved": "https://registry.npmjs.org/micromatch/-/micromatch-4.0.8.tgz",
+      "integrity": "sha512-PXwfBhYu0hBCPw8Dn0E+WDYb7af3dSLVWKi3HGv84IdF4TyFoC0ysxFd0Goxw7nSv4T/PzEJQxsYsEiFCKo2BA==",
       "dev": true,
-      "license": "MIT",
       "dependencies": {
-        "braces": "^3.0.2",
+        "braces": "^3.0.3",
         "picomatch": "^2.3.1"
       },
       "engines": {
@@ -10760,9 +10685,10 @@
       }
     },
     "node_modules/picocolors": {
-      "version": "1.0.0",
+      "version": "1.1.1",
-      "dev": true,
+      "resolved": "https://registry.npmjs.org/picocolors/-/picocolors-1.1.1.tgz",
-      "license": "ISC"
+      "integrity": "sha512-xceH2snhtb5M9liqDsmEw56le376mTZkEX/jEb/RxNFyegNul7eNslCXP9FDj/Lcu0X8KEyMceP2ntpaHrDEVA==",
+      "dev": true
     },
     "node_modules/picomatch": {
       "version": "2.3.1",
@@ -11524,9 +11450,10 @@
       "license": "MIT"
     },
     "node_modules/semver": {
-      "version": "6.3.0",
+      "version": "6.3.1",
+      "resolved": "https://registry.npmjs.org/semver/-/semver-6.3.1.tgz",
+      "integrity": "sha512-BR7VvDCVHO+q2xBEWskxS6DJE1qRnb7DxzUrogb71CWoSficBxYsiAGd+Kl0mmq/MprG9yArRkyrQxTO6XjMzA==",
       "dev": true,
-      "license": "ISC",
       "bin": {
         "semver": "bin/semver.js"
       }
@@ -12147,14 +12074,6 @@
       "dev": true,
       "license": "BSD-3-Clause"
     },
-    "node_modules/to-fast-properties": {
-      "version": "2.0.0",
-      "dev": true,
-      "license": "MIT",
-      "engines": {
-        "node": ">=4"
-      }
-    },
     "node_modules/to-regex-range": {
       "version": "5.0.1",
       "resolved": "https://registry.npmjs.org/to-regex-range/-/to-regex-range-5.0.1.tgz",
@@ -12235,12 +12154,10 @@
       }
     },
     "node_modules/ts-jest/node_modules/semver": {
-      "version": "7.3.8",
+      "version": "7.7.3",
+      "resolved": "https://registry.npmjs.org/semver/-/semver-7.7.3.tgz",
+      "integrity": "sha512-SdsKMrI9TdgjdweUSR9MweHA4EJ8YxHn8DFaDisvhVlUOe4BF1tLD7GAj0lIqWVl+dPb/rExr0Btby5loQm20Q==",
       "dev": true,
-      "license": "ISC",
-      "dependencies": {
-        "lru-cache": "^6.0.0"
-      },
       "bin": {
         "semver": "bin/semver.js"
       },
@@ -12917,10 +12834,10 @@
     },
     "workflow-parser": {
       "name": "@actions/workflow-parser",
-      "version": "0.3.20",
+      "version": "0.3.23",
       "license": "MIT",
       "dependencies": {
-        "@actions/expressions": "^0.3.20",
+        "@actions/expressions": "^0.3.23",
         "cronstrue": "^2.21.0",
         "yaml": "^2.0.0-8"
       },

package.json

@@ -1,6 +1,7 @@
 {
   "name": "actions-languageservices",
   "private": true,
+  "type": "module",
   "workspaces": [
     "./expressions",
     "./workflow-parser",

script/minify-json.js

@@ -0,0 +1,43 @@
+#!/usr/bin/env node
+
+/**
+ * Minifies JSON files by removing whitespace.
+ *
+ * Usage: node script/minify-json.js <file1.json> <file2.json> ...
+ *
+ * For each input file, creates a corresponding .min.json file.
+ * Example: src/data.json -> src/data.min.json
+ */
+
+import {promises as fs} from "fs";
+import path from "path";
+
+const files = process.argv.slice(2);
+
+if (files.length === 0) {
+  console.error("Usage: node script/minify-json.js <file1.json> <file2.json> ...");
+  process.exit(1);
+}
+
+for (const file of files) {
+  try {
+    const content = await fs.readFile(file, "utf8");
+    const data = JSON.parse(content);
+    const minified = JSON.stringify(data);
+
+    // Replace .json with .min.json
+    const ext = path.extname(file);
+    const outputFile = file.slice(0, -ext.length) + ".min" + ext;
+
+    await fs.writeFile(outputFile, minified);
+
+    const originalSize = Buffer.byteLength(content, "utf8");
+    const minifiedSize = Buffer.byteLength(minified, "utf8");
+    const savings = ((1 - minifiedSize / originalSize) * 100).toFixed(1);
+
+    console.log(`${file} -> ${outputFile} (${savings}% smaller)`);
+  } catch (err) {
+    console.error(`Error processing ${file}:`, err);
+    process.exit(1);
+  }
+}

workflow-parser/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@actions/workflow-parser",
-  "version": "0.3.20",
+  "version": "0.3.23",
   "license": "MIT",
   "type": "module",
   "source": "./src/index.ts",
@@ -38,19 +38,22 @@
     "format-check": "prettier --check '**/*.ts'",
     "lint": "eslint 'src/**/*.ts'",
     "lint-fix": "eslint --fix 'src/**/*.ts'",
+    "minify-json": "node ../script/minify-json.js src/workflow-v1.0.json",
+    "prebuild": "npm run minify-json",
     "prepublishOnly": "npm run build && npm run test",
+    "pretest": "npm run minify-json",
     "test": "NODE_OPTIONS=\"--experimental-vm-modules\" jest",
     "test-xlang": "NODE_OPTIONS=\"--experimental-vm-modules\" jest --testPathPattern xlang",
     "test-watch": "NODE_OPTIONS=\"--experimental-vm-modules\" jest --watch",
     "watch": "tsc --build tsconfig.build.json --watch"
   },
   "dependencies": {
-    "@actions/expressions": "^0.3.20",
+    "@actions/expressions": "^0.3.23",
     "cronstrue": "^2.21.0",
     "yaml": "^2.0.0-8"
   },
   "engines": {
-    "node": ">= 16.15"
+    "node": ">= 18"
   },
   "files": [
     "dist/**/*"

workflow-parser/src/model/converter/cron.test.ts

@@ -1,4 +1,4 @@
-import {isValidCron, getCronDescription} from "./cron";
+import {isValidCron, getCronDescription, hasCronIntervalLessThan5Minutes} from "./cron";
 
 describe("cron", () => {
   describe("valid cron", () => {
@@ -66,14 +66,54 @@ describe("cron", () => {
 
   describe("getCronDescription", () => {
     it(`Produces a sentence for valid cron`, () => {
-      expect(getCronDescription("0 * * * *")).toEqual(
+      expect(getCronDescription("0 * * * *")).toEqual("Runs every hour");
-        "Runs every hour\n\n" +
-          "Actions schedules run at most every 5 minutes. [Learn more](https://docs.github.com/actions/using-workflows/workflow-syntax-for-github-actions#onschedule)"
-      );
     });
 
     it(`Returns nothing for invalid cron`, () => {
       expect(getCronDescription("* * * * * *")).toBeUndefined();
     });
   });
+
+  describe("hasCronIntervalLessThan5Minutes", () => {
+    it("returns true for step expressions with interval < 5 min", () => {
+      expect(hasCronIntervalLessThan5Minutes("*/1 * * * *")).toBe(true);
+      expect(hasCronIntervalLessThan5Minutes("*/4 * * * *")).toBe(true);
+    });
+
+    it("returns false for step expressions with interval >= 5 min", () => {
+      expect(hasCronIntervalLessThan5Minutes("*/5 * * * *")).toBe(false);
+      expect(hasCronIntervalLessThan5Minutes("*/15 * * * *")).toBe(false);
+    });
+
+    it("returns true for comma-separated values with gap < 5 min", () => {
+      expect(hasCronIntervalLessThan5Minutes("0,2,4 * * * *")).toBe(true);
+      expect(hasCronIntervalLessThan5Minutes("0,10,12 * * * *")).toBe(true);
+    });
+
+    it("returns false for comma-separated values with gap >= 5 min", () => {
+      expect(hasCronIntervalLessThan5Minutes("0,10,20 * * * *")).toBe(false);
+      expect(hasCronIntervalLessThan5Minutes("0,30 * * * *")).toBe(false);
+    });
+
+    it("returns true for comma-separated values with wrap-around gap < 5 min", () => {
+      expect(hasCronIntervalLessThan5Minutes("0,58 * * * *")).toBe(true);
+      expect(hasCronIntervalLessThan5Minutes("2,59 * * * *")).toBe(true);
+    });
+
+    it("returns true for * (every minute)", () => {
+      expect(hasCronIntervalLessThan5Minutes("* * * * *")).toBe(true);
+    });
+
+    it("returns true for range expressions (runs every minute in range)", () => {
+      expect(hasCronIntervalLessThan5Minutes("0-4 * * * *")).toBe(true);
+    });
+
+    it("returns false for single value (hourly)", () => {
+      expect(hasCronIntervalLessThan5Minutes("0 * * * *")).toBe(false);
+    });
+
+    it("returns false for invalid cron", () => {
+      expect(hasCronIntervalLessThan5Minutes("invalid")).toBe(false);
+    });
+  });
 });

workflow-parser/src/model/converter/cron.ts

@@ -8,6 +8,78 @@ type Range = {
   names?: Record<string, number>;
 };
 
+/**
+ * Checks if a cron expression specifies an interval shorter than 5 minutes.
+ * GitHub Actions schedules run at most every 5 minutes, so intervals < 5 min won't work as expected.
+ */
+export function hasCronIntervalLessThan5Minutes(cron: string): boolean {
+  if (!isValidCron(cron)) {
+    return false;
+  }
+
+  const parts = cron.split(/ +/);
+  const minutePart = parts[0];
+
+  // Parse the minute field to determine the effective interval
+  return getMinuteInterval(minutePart) < 5;
+}
+
+/**
+ * Gets the minimum interval in minutes between cron executions based on the minute field.
+ * Returns 60 if there's only one execution per hour, otherwise returns the minimum gap.
+ */
+function getMinuteInterval(minutePart: string): number {
+  // Handle step expressions like */1, */3, 0-59/2
+  if (minutePart.includes("/")) {
+    const [, step] = minutePart.split("/");
+    const stepNum = parseInt(step, 10);
+    if (!isNaN(stepNum) && stepNum > 0) {
+      return stepNum;
+    }
+  }
+
+  // Handle comma-separated values like 0,2,4 or 0,1,5,10
+  if (minutePart.includes(",")) {
+    const values = minutePart
+      .split(",")
+      .map(v => parseInt(v, 10))
+      .filter(n => !isNaN(n))
+      .sort((a, b) => a - b);
+    if (values.length >= 2) {
+      let minGap = 60;
+      for (let i = 1; i < values.length; i++) {
+        const gap = values[i] - values[i - 1];
+        if (gap < minGap) {
+          minGap = gap;
+        }
+      }
+      // Check wrap-around gap from last minute to first minute of next hour
+      const wrapGap = values[0] + 60 - values[values.length - 1];
+      if (wrapGap < minGap) {
+        minGap = wrapGap;
+      }
+      return minGap;
+    }
+  }
+
+  // Handle range expressions like 0-4 (runs every minute from 0-4)
+  if (minutePart.includes("-") && !minutePart.includes("/")) {
+    const [start, end] = minutePart.split("-").map(v => parseInt(v, 10));
+    if (!isNaN(start) && !isNaN(end) && end > start) {
+      // A range without step means every minute in that range
+      return 1;
+    }
+  }
+
+  // * means every minute
+  if (minutePart === "*") {
+    return 1;
+  }
+
+  // Single value or unrecognized pattern - assume hourly (60 min interval)
+  return 60;
+}
+
 export function isValidCron(cron: string): boolean {
   // https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#schedule
 
@@ -46,11 +118,7 @@ export function getCronDescription(cronspec: string): string | undefined {
   }
 
   // Make first character lowercase
-  let result = "Runs " + desc.charAt(0).toLowerCase() + desc.slice(1);
+  return "Runs " + desc.charAt(0).toLowerCase() + desc.slice(1);
-  result +=
-    "\n\nActions schedules run at most every 5 minutes." +
-    " [Learn more](https://docs.github.com/actions/using-workflows/workflow-syntax-for-github-actions#onschedule)";
-  return result;
 }
 
 function validateCronPart(value: string, range: Range, allowSeparators = true): boolean {

workflow-parser/src/model/converter/events.ts

@@ -158,7 +158,7 @@ function convertSchedule(context: TemplateContext, token: SequenceToken): Schedu
         const cron = schedule.value.assertString(`schedule cron`);
         // Validate the cron string
         if (!isValidCron(cron.value)) {
-          context.error(cron, "Invalid cron string");
+          context.error(cron, "Invalid cron expression. Expected format: '* * * * *' (minute hour day month weekday)");
         }
         result.push({cron: cron.value});
       } else {

workflow-parser/src/workflows/workflow-schema.ts

@@ -1,6 +1,6 @@
 import {JSONObjectReader} from "../templates/json-object-reader";
 import {TemplateSchema} from "../templates/schema";
-import WorkflowSchema from "../workflow-v1.0.json";
+import WorkflowSchema from "../workflow-v1.0.min.json";
 
 let schema: TemplateSchema;