Add example showing how to setup an MCP server for a workspace

[scuffi]

Codemode already runs model-written JavaScript in an isolated Dynamic Worker, and Computer already provides bounded tools for working with a durable workspace. This example shows how to compose those pieces without adding another Computer backend or executor. All implementation code stays in examples/codemode.

The example creates an internal MCP server from Computer's read, ls, write, edit, and exec tools. Codemode's codeMcpServer() discovers those tools, generates their JavaScript types, and exposes them to MCP clients as one code tool.

MCP client
  → code
  → Codemode DynamicWorkerExecutor
  → Computer read / ls / write / edit / exec
  → durable Workspace

The main composition is intentionally small:

const computer = createComputerMcpServer(workspace);
const server = await codeMcpServer({
  server: computer,
  executor: new DynamicWorkerExecutor({
    loader: env.LOADER,
    globalOutbound: null,
  }),
});

Code running in the Codemode sandbox can then use the native Computer tools together:

async () => {
  await codemode.write({
    path: "/workspace/message.txt",
    content: "hello from codemode"
  });
  const file = await codemode.read({ path: "/workspace/message.txt" });
  const shell = await codemode.exec({ command: "pwd" });
  return { content: file.content, cwd: shell.stdout.trim() };
}

To try it locally, run:

npm install
npm run dev --workspace @example/computer-codemode

Then connect a Streamable HTTP MCP client to http://127.0.0.1:8787/mcp. The local harness is stateless and accepts POST only; it does not open a session-bound event stream.

The integration test connects with a real MCP client, checks that only code is public, exercises all five Computer tools through Codemode's Dynamic Worker, and confirms that files persist across calls. The example README documents the architecture, local setup, and trust boundary. A public deployment would still need tenant-derived Workspace identity, authentication, authorization, limits, and storage quotas.

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/@cloudflare/computer@28

commit: 652d3bd

[aron-cf]

Trying to figure out if we need this on top of the existing backend. I'm not sure what it would be used for. What are your thoughts?

[aron-cf]

Looking good, left some early comments.

[aron-cf]

nit: We call it Code Mode, so camel case it'd be CodeMode, though lower case I still prefer codemode over codeMode...

Suggested change

	describe("Computer Codemode MCP", () => {
	describe("Computer Code Mode MCP", () => {

[aron-cf]

nit: MCP over Mcp

Suggested change

	export function createComputerMcpServer(workspace: WorkspaceClient) {
	export function createComputerMCPServer(workspace: WorkspaceClient) {

[aron-cf]

We should probably make this an option on createAITools, also I don't think it should override the user provided one... or at least it should use the provided one as a cap...

[aron-cf]

I don't like this interface much. As this is the tool description for exec, we probably need something a lot more detailed here to get good results. Check out the tool prompts in the think example.

[aron-cf]

This is weird, do you know why it needs to extend DurableObject here? Is it to do with the generics? We should fix this if so.

[aron-cf]

Hey @agent-think can you deploy a version of this MCP server example, then can you:

(1) do some light smoke testing of file based workflows.
(2) report back with the full interface of the Code Mode server that you were able to discover using the server (without using the source code as a reference)