diff --git a/actions-languageservice/src/complete.ts b/actions-languageservice/src/complete.ts
index 1ba93ad..97c8e84 100644
--- a/actions-languageservice/src/complete.ts
+++ b/actions-languageservice/src/complete.ts
@@ -1,6 +1,8 @@
 import {complete as completeExpression} from "@github/actions-expressions";
 import {convertWorkflowTemplate, isSequence, isString, parseWorkflow} from "@github/actions-workflow-parser";
 import {ErrorPolicy} from "@github/actions-workflow-parser/model/convert";
+import {DefinitionType} from "@github/actions-workflow-parser/templates/schema/definition-type";
+import {StringDefinition} from "@github/actions-workflow-parser/templates/schema/string-definition";
 import {CLOSE_EXPRESSION, OPEN_EXPRESSION} from "@github/actions-workflow-parser/templates/template-constants";
 import {TemplateToken} from "@github/actions-workflow-parser/templates/tokens/index";
 import {MappingToken} from "@github/actions-workflow-parser/templates/tokens/mapping-token";
@@ -72,9 +74,10 @@ export async function complete(
   if (token) {
     // We don't have any way of specifying that a token in the workflow schema is alwyas an expression. For now these
     // are only the job and step level `if` nodes, so check for those here.
-    const isIfKey = keyToken && isString(keyToken) && keyToken.value === "if";
+    const isExpression =
+      token.definition?.definitionType === DefinitionType.String && (token.definition as StringDefinition).isExpression;
     const containsExpression = isString(token) && token.value.indexOf(OPEN_EXPRESSION) >= 0;
-    if (isString(token) && (isIfKey || containsExpression)) {
+    if (isString(token) && (isExpression || containsExpression)) {
       const currentInput = token.value;
 
       // Transform the overall position into a node relative position
diff --git a/actions-languageservice/src/validate.expressions.test.ts b/actions-languageservice/src/validate.expressions.test.ts
index c73f8c8..9a78a59 100644
--- a/actions-languageservice/src/validate.expressions.test.ts
+++ b/actions-languageservice/src/validate.expressions.test.ts
@@ -7,7 +7,13 @@ describe("expression validation", () => {
     const result = await validate(
       createDocument(
         "wf.yaml",
-        "on: push\nrun-name: name-${{ github.does-not-exist }}\njobs:\n  build:\n    runs-on: ubuntu-latest\n    steps:\n    - run: echo"
+        `on: push
+run-name: name-\${{ github.does-not-exist }}
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - run: echo`
       )
     );
 
@@ -73,4 +79,38 @@ jobs:
 
     expect(result).toEqual([]);
   });
+
+  describe("expressions without markers", () => {
+    it("access invalid context field", async () => {
+      const result = await validate(
+        createDocument(
+          "wf.yaml",
+          `on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - run: echo
+        if: github.does-not-exist`
+        )
+      );
+
+      expect(result).toEqual([
+        {
+          message: "Context access might be invalid: does-not-exist",
+          range: {
+            start: {
+              character: 12,
+              line: 6
+            },
+            end: {
+              character: 33,
+              line: 6
+            }
+          },
+          severity: DiagnosticSeverity.Warning
+        }
+      ]);
+    });
+  });
 });