diff --git a/dotnet/test/Harness/E2ETestContext.cs b/dotnet/test/Harness/E2ETestContext.cs
index 00fc32075..62acd580f 100644
--- a/dotnet/test/Harness/E2ETestContext.cs
+++ b/dotnet/test/Harness/E2ETestContext.cs
@@ -94,13 +94,13 @@ public IReadOnlyDictionary<string, string> GetEnvironment()
         Cwd = WorkDir,
         CliPath = GetCliPath(_repoRoot),
         Environment = GetEnvironment(),
-        GitHubToken = !string.IsNullOrEmpty(Environment.GetEnvironmentVariable("CI")) ? "fake-token-for-e2e-tests" : null,
+        GitHubToken = !string.IsNullOrEmpty(Environment.GetEnvironmentVariable("GITHUB_ACTIONS")) ? "fake-token-for-e2e-tests" : null,
     });
 
     public async ValueTask DisposeAsync()
     {
         // Skip writing snapshots in CI to avoid corrupting them on test failures
-        var isCI = !string.IsNullOrEmpty(Environment.GetEnvironmentVariable("CI"));
+        var isCI = !string.IsNullOrEmpty(Environment.GetEnvironmentVariable("GITHUB_ACTIONS"));
         await _proxy.StopAsync(skipWritingCache: isCI);
 
         try { if (Directory.Exists(HomeDir)) Directory.Delete(HomeDir, true); } catch { }
diff --git a/go/internal/e2e/testharness/context.go b/go/internal/e2e/testharness/context.go
index cefb87b58..b9edab1e5 100644
--- a/go/internal/e2e/testharness/context.go
+++ b/go/internal/e2e/testharness/context.go
@@ -166,7 +166,7 @@ func (c *TestContext) NewClient() *copilot.Client {
 	}
 
 	// Use fake token in CI to allow cached responses without real auth
-	if os.Getenv("CI") == "true" {
+	if os.Getenv("GITHUB_ACTIONS") == "true" {
 		options.GitHubToken = "fake-token-for-e2e-tests"
 	}
 
diff --git a/nodejs/test/e2e/harness/sdkTestContext.ts b/nodejs/test/e2e/harness/sdkTestContext.ts
index 4986d1299..a5cf2ec57 100644
--- a/nodejs/test/e2e/harness/sdkTestContext.ts
+++ b/nodejs/test/e2e/harness/sdkTestContext.ts
@@ -13,6 +13,8 @@ import { CopilotClient } from "../../../src";
 import { CapiProxy } from "./CapiProxy";
 import { retry } from "./sdkTestHelper";
 
+export const isCI = process.env.GITHUB_ACTIONS === "true";
+
 const __filename = fileURLToPath(import.meta.url);
 const __dirname = dirname(__filename);
 const SNAPSHOTS_DIR = resolve(__dirname, "../../../../test/snapshots");
@@ -42,7 +44,7 @@ export async function createSdkTestContext({
         logLevel: logLevel || "error",
         cliPath: process.env.COPILOT_CLI_PATH,
         // Use fake token in CI to allow cached responses without real auth
-        githubToken: process.env.CI === "true" ? "fake-token-for-e2e-tests" : undefined,
+        githubToken: isCI ? "fake-token-for-e2e-tests" : undefined,
     });
 
     const harness = { homeDir, workDir, openAiEndpoint, copilotClient, env };
diff --git a/nodejs/test/e2e/session.test.ts b/nodejs/test/e2e/session.test.ts
index 9d067a8ef..93731d617 100644
--- a/nodejs/test/e2e/session.test.ts
+++ b/nodejs/test/e2e/session.test.ts
@@ -2,7 +2,7 @@ import { rm } from "fs/promises";
 import { describe, expect, it, onTestFinished } from "vitest";
 import { ParsedHttpExchange } from "../../../test/harness/replayingCapiProxy.js";
 import { CopilotClient, approveAll } from "../../src/index.js";
-import { createSdkTestContext } from "./harness/sdkTestContext.js";
+import { createSdkTestContext, isCI } from "./harness/sdkTestContext.js";
 import { getFinalAssistantMessage, getNextEventOfType } from "./harness/sdkTestHelper.js";
 
 describe("Sessions", async () => {
@@ -187,7 +187,7 @@ describe("Sessions", async () => {
         // Resume using a new client
         const newClient = new CopilotClient({
             env,
-            githubToken: process.env.CI === "true" ? "fake-token-for-e2e-tests" : undefined,
+            githubToken: isCI ? "fake-token-for-e2e-tests" : undefined,
         });
 
         onTestFinished(() => newClient.forceStop());
diff --git a/python/e2e/test_session.py b/python/e2e/test_session.py
index 47cb1b5ae..13e749507 100644
--- a/python/e2e/test_session.py
+++ b/python/e2e/test_session.py
@@ -183,7 +183,9 @@ async def test_should_resume_a_session_using_a_new_client(self, ctx: E2ETestCont
         assert "2" in answer.data.content
 
         # Resume using a new client
-        github_token = "fake-token-for-e2e-tests" if os.environ.get("CI") == "true" else None
+        github_token = (
+            "fake-token-for-e2e-tests" if os.environ.get("GITHUB_ACTIONS") == "true" else None
+        )
         new_client = CopilotClient(
             {
                 "cli_path": ctx.cli_path,
diff --git a/python/e2e/testharness/context.py b/python/e2e/testharness/context.py
index eb0c44081..c03088912 100644
--- a/python/e2e/testharness/context.py
+++ b/python/e2e/testharness/context.py
@@ -60,7 +60,9 @@ async def setup(self):
 
         # Create the shared client (like Node.js/Go do)
         # Use fake token in CI to allow cached responses without real auth
-        github_token = "fake-token-for-e2e-tests" if os.environ.get("CI") == "true" else None
+        github_token = (
+            "fake-token-for-e2e-tests" if os.environ.get("GITHUB_ACTIONS") == "true" else None
+        )
         self._client = CopilotClient(
             {
                 "cli_path": self.cli_path,
diff --git a/test/harness/replayingCapiProxy.ts b/test/harness/replayingCapiProxy.ts
index 6864731df..1a8fbc243 100644
--- a/test/harness/replayingCapiProxy.ts
+++ b/test/harness/replayingCapiProxy.ts
@@ -311,7 +311,8 @@ export class ReplayingCapiProxy extends CapturingHttpProxy {
 
         // Fallback to normal proxying if no cached response found
         // This implicitly captures the new exchange too
-        if (process.env.CI === "true") {
+        const isCI = process.env.GITHUB_ACTIONS === "true";
+        if (isCI) {
           await exitWithNoMatchingRequestError(
             options,
             state.testInfo,