diff --git a/actions/setup/js/validate_lockdown_requirements_templates.cjs b/actions/setup/js/validate_lockdown_requirements_templates.cjs
index ac564c22cec..e553ca159ff 100644
--- a/actions/setup/js/validate_lockdown_requirements_templates.cjs
+++ b/actions/setup/js/validate_lockdown_requirements_templates.cjs
@@ -40,14 +40,17 @@ const TEMPLATE_CONTEXT = {
   strict_compile_command: "gh aw compile --strict",
 };
 
+/** @returns {string} Rendered lockdown token error message with documentation URL */
 function renderLockdownTokenErrorMessage() {
   return renderTemplate(LOCKDOWN_TOKEN_ERROR_TEMPLATE, TEMPLATE_CONTEXT);
 }
 
+/** @returns {string} Rendered public strict mode error message with compile command and documentation URL */
 function renderPublicStrictModeErrorMessage() {
   return renderTemplate(PUBLIC_STRICT_MODE_ERROR_TEMPLATE, TEMPLATE_CONTEXT);
 }
 
+/** @returns {string} Rendered pull_request_target security error message with documentation URL */
 function renderPullRequestTargetErrorMessage() {
   return renderTemplate(PULL_REQUEST_TARGET_ERROR_TEMPLATE, TEMPLATE_CONTEXT);
 }
diff --git a/actions/setup/js/validate_lockdown_requirements_templates.test.cjs b/actions/setup/js/validate_lockdown_requirements_templates.test.cjs
new file mode 100644
index 00000000000..f05526d206c
--- /dev/null
+++ b/actions/setup/js/validate_lockdown_requirements_templates.test.cjs
@@ -0,0 +1,156 @@
+// @ts-check
+const { renderLockdownTokenErrorMessage, renderPublicStrictModeErrorMessage, renderPullRequestTargetErrorMessage } = require("./validate_lockdown_requirements_templates.cjs");
+
+// Content-contract tests below assert specific phrasing and key terms from each template.
+// They document intentional wording and will fail on purposeful rewording — that is the intent.
+describe("validate_lockdown_requirements_templates", () => {
+  describe("renderLockdownTokenErrorMessage", () => {
+    it("returns a non-empty string", () => {
+      const message = renderLockdownTokenErrorMessage();
+      expect(message).toBeTypeOf("string");
+      expect(message.length).toBeGreaterThan(0);
+    });
+
+    it("includes the auth documentation URL", () => {
+      const message = renderLockdownTokenErrorMessage();
+      expect(message).toContain("https://github.com/github/gh-aw/blob/main/docs/src/content/docs/reference/auth.mdx");
+    });
+
+    it("includes GH_AW_GITHUB_TOKEN recommendation", () => {
+      const message = renderLockdownTokenErrorMessage();
+      expect(message).toContain("GH_AW_GITHUB_TOKEN (recommended)");
+    });
+
+    it("includes GH_AW_GITHUB_MCP_SERVER_TOKEN as alternative", () => {
+      const message = renderLockdownTokenErrorMessage();
+      expect(message).toContain("GH_AW_GITHUB_MCP_SERVER_TOKEN (alternative)");
+    });
+
+    it("includes the gh aw secrets set command", () => {
+      const message = renderLockdownTokenErrorMessage();
+      expect(message).toContain("gh aw secrets set GH_AW_GITHUB_TOKEN");
+    });
+
+    it("mentions lockdown mode is enabled", () => {
+      const message = renderLockdownTokenErrorMessage();
+      expect(message).toContain("Lockdown mode is enabled");
+    });
+
+    it("does not contain unreplaced {auth_docs_url} placeholder", () => {
+      const message = renderLockdownTokenErrorMessage();
+      expect(message).not.toContain("{auth_docs_url}");
+    });
+  });
+
+  describe("renderPublicStrictModeErrorMessage", () => {
+    it("returns a non-empty string", () => {
+      const message = renderPublicStrictModeErrorMessage();
+      expect(message).toBeTypeOf("string");
+      expect(message.length).toBeGreaterThan(0);
+    });
+
+    it("includes the security documentation URL", () => {
+      const message = renderPublicStrictModeErrorMessage();
+      expect(message).toContain("https://github.com/github/gh-aw/blob/main/docs/src/content/docs/reference/security.mdx");
+    });
+
+    it("includes the strict compile command", () => {
+      const message = renderPublicStrictModeErrorMessage();
+      expect(message).toContain("gh aw compile --strict");
+    });
+
+    it("mentions public repository context", () => {
+      const message = renderPublicStrictModeErrorMessage();
+      expect(message).toContain("public repository");
+    });
+
+    it("mentions strict mode", () => {
+      const message = renderPublicStrictModeErrorMessage();
+      expect(message).toContain("strict mode");
+    });
+
+    it("does not contain unreplaced {strict_compile_command} placeholder", () => {
+      const message = renderPublicStrictModeErrorMessage();
+      expect(message).not.toContain("{strict_compile_command}");
+    });
+
+    it("does not contain unreplaced {security_docs_url} placeholder", () => {
+      const message = renderPublicStrictModeErrorMessage();
+      expect(message).not.toContain("{security_docs_url}");
+    });
+  });
+
+  describe("renderPullRequestTargetErrorMessage", () => {
+    it("returns a non-empty string", () => {
+      const message = renderPullRequestTargetErrorMessage();
+      expect(message).toBeTypeOf("string");
+      expect(message.length).toBeGreaterThan(0);
+    });
+
+    it("includes the security documentation URL", () => {
+      const message = renderPullRequestTargetErrorMessage();
+      expect(message).toContain("https://github.com/github/gh-aw/blob/main/docs/src/content/docs/reference/security.mdx");
+    });
+
+    it("mentions the pull_request_target event", () => {
+      const message = renderPullRequestTargetErrorMessage();
+      expect(message).toContain("pull_request_target");
+    });
+
+    it("mentions pwn request security risk", () => {
+      const message = renderPullRequestTargetErrorMessage();
+      expect(message).toContain("pwn request");
+    });
+
+    it("mentions public repositories", () => {
+      const message = renderPullRequestTargetErrorMessage();
+      expect(message).toContain("public repositories");
+    });
+
+    it("suggests using the pull_request event instead", () => {
+      const message = renderPullRequestTargetErrorMessage();
+      expect(message).toContain("pull_request event instead");
+    });
+
+    it("does not contain unreplaced {security_docs_url} placeholder", () => {
+      const message = renderPullRequestTargetErrorMessage();
+      expect(message).not.toContain("{security_docs_url}");
+    });
+  });
+
+  describe("cross-function checks", () => {
+    it("each render function returns a distinct message", () => {
+      const lockdown = renderLockdownTokenErrorMessage();
+      const strictMode = renderPublicStrictModeErrorMessage();
+      const prTarget = renderPullRequestTargetErrorMessage();
+
+      expect(lockdown).not.toBe(strictMode);
+      expect(lockdown).not.toBe(prTarget);
+      expect(strictMode).not.toBe(prTarget);
+    });
+
+    it("lockdown message does not contain strict mode content", () => {
+      const message = renderLockdownTokenErrorMessage();
+      expect(message).not.toContain("gh aw compile --strict");
+    });
+
+    it("strict mode message does not contain lockdown token content", () => {
+      const message = renderPublicStrictModeErrorMessage();
+      expect(message).not.toContain("GH_AW_GITHUB_TOKEN");
+    });
+
+    it("module exposes exactly the expected exports", () => {
+      const mod = require("./validate_lockdown_requirements_templates.cjs");
+      const keys = Object.keys(mod);
+      expect(keys).toHaveLength(3);
+      expect(keys).toEqual(expect.arrayContaining(["renderLockdownTokenErrorMessage", "renderPublicStrictModeErrorMessage", "renderPullRequestTargetErrorMessage"]));
+    });
+
+    it("no message contains unreplaced placeholders", () => {
+      const messages = [renderLockdownTokenErrorMessage(), renderPublicStrictModeErrorMessage(), renderPullRequestTargetErrorMessage()];
+      for (const message of messages) {
+        expect(message).not.toMatch(/\{[A-Za-z][A-Za-z0-9_]*\}/);
+      }
+    });
+  });
+});