test: update tests for --allow-unrestricted-paths behavior change

- Update the legacy 'validatePath allows all paths if roots are undefined'
  test to explicitly pass allowUnrestrictedPaths: true, matching the new
  behavior where the old permissive default requires an opt-in flag.
- Add a new test verifying that paths outside tmpdir are denied by default
  when the client never negotiates roots (and the flag is not set).
- Expose allowUnrestrictedPaths in withMcpContext() test helper.
- Run npm run gen to update README and telemetry metrics for the new flag.

Author: herdiyana256

README.md

@@ -744,6 +744,11 @@ The Chrome DevTools MCP server supports the following configuration option:
   - **Type:** boolean
   - **Default:** `false`
 
+- **`--allowUnrestrictedPaths`/ `--allow-unrestricted-paths`**
+  If set, disables the default path restriction that applies when the MCP client does not negotiate the roots capability. By default, file-writing tools are restricted to the OS temp directory when no roots are configured. Use this only when connecting a trusted local client that does not implement MCP roots and requires access to paths outside the temp directory.
+  - **Type:** boolean
+  - **Default:** `false`
+
 <!-- END AUTO GENERATED OPTIONS -->
 
 Pass them via the `args` property in the JSON configuration. For example:

src/telemetry/flag_usage_metrics.json

@@ -347,5 +347,13 @@
   {
     "name": "screenshot_max_height_present",
     "flagType": "boolean"
+  },
+  {
+    "name": "allow_unrestricted_paths_present",
+    "flagType": "boolean"
+  },
+  {
+    "name": "allow_unrestricted_paths",
+    "flagType": "boolean"
   }
 ]

tests/McpContext.test.ts

@@ -278,10 +278,23 @@ describe('McpContext', () => {
     });
   });
 
-  it('validatePath allows all paths if roots are undefined (legacy)', async () => {
+  it('validatePath allows all paths if roots are undefined and allowUnrestrictedPaths is set', async () => {
+    await withMcpContext(
+      async (_response, context) => {
+        context.setRoots(undefined);
+        await context.validatePath(path.resolve(os.homedir(), 'anywhere.txt'));
+      },
+      {allowUnrestrictedPaths: true},
+    );
+  });
+
+  it('validatePath denies paths outside tmpdir if roots are undefined and allowUnrestrictedPaths is not set', async () => {
     await withMcpContext(async (_response, context) => {
-      context.setRoots(undefined);
-      await context.validatePath(path.resolve(os.homedir(), 'anywhere.txt'));
+      // setRoots() never called — simulates a client that skips roots capability.
+      const outsidePath = path.resolve(os.homedir(), 'anywhere.txt');
+      await assert.rejects(context.validatePath(outsidePath), /Access denied/);
+      // Temp dir must still be reachable.
+      await context.validatePath(path.join(os.tmpdir(), 'test.txt'));
     });
   });
 

tests/utils.ts

@@ -121,6 +121,7 @@ export async function withMcpContext(
     args?: string[];
     blockedUrlPattern?: string[];
     allowedUrlPattern?: string[];
+    allowUnrestrictedPaths?: boolean;
   } = {},
   args: Partial<ParsedArguments> = {},
 ) {
@@ -138,6 +139,7 @@ export async function withMcpContext(
         performanceCrux: options.performanceCrux ?? true,
         allowList: options.allowedUrlPattern,
         blocklist: options.blockedUrlPattern,
+        allowUnrestrictedPaths: options.allowUnrestrictedPaths ?? false,
       },
       Locator,
     );