Add harness.fetch(request) to OpenCodeHarness. It would serve OpenCode's HTTP API from the Durable Object, so the OpenCode CLI can attach to a hosted session:

npx @opencode/cli@2 --server <origin>/agents/open-code-agent/<name> --session <ses_id>

export class OpenCodeAgent extends DurableObject<Env> {
  async fetch(request: Request) {
    return this.harness.fetch(stripAgentPrefix(request));
  }
}

Blocked on upstream

@opencode/sdk builds the embedded server's handler (host.fetch) but doesn't return it from OpenCodeWorkerd.create. Asked for it in anomalyco/opencode#54803.

#2483 got the handler by redefining OpenCode.make in @opencode/client and catching its fetch option with AsyncLocalStorage. We're not taking that: it's a monkey-patch, and it breaks when the SDK and the app resolve different copies of @opencode/client.

When it ships

• Bump @opencode/sdk and @opencode/plugin.
• harness.fetch(request) holds a lease and calls (await this.#open()).fetch(request), so it counts as activity for the idle close.
• In the example, add a route under /agents/open-code-agent/<name> that strips the agent prefix (src/cli.ts in Harness opencode #2483), plus a README section on attaching the CLI.
• Test: a GET for a session through harness.fetch returns the same session as harness.sessions.list().