Switchboard

Switchboard lets Codex and Claude Code communicate with the sessions you already have open on your Mac. It runs as a local Model Context Protocol (MCP) server in both clients, with tools to find running sessions, read recent conversation text, and send a message to a particular session.

The point is to keep working where you are. If Claude needs a review from Codex, it can ask the Codex session that already knows the project, then read its response. Each session keeps its conversation, workspace, model, and permissions. Switchboard connects those sessions; it doesn't launch replacement agents or move their work into a separate orchestration system.

This is an experimental integration with version-sensitive local interfaces. The verified path connects Codex desktop tasks and Claude Code sessions in Claude Desktop. Independent terminal sessions are not verified, and ordinary Claude Chat and Cowork conversations are outside its scope.

Install

You need macOS, Node.js 24 or later with node:sqlite, and both agent clients installed under the same local account. Tests for this extraction ran on Node.js 26.8.2. There are no package dependencies, API keys, or hosted services to configure for Switchboard itself. The agents retain their own authentication and usage costs.

Clone the repository and run the tests:

git clone https://github.com/chrischabot/agent-switchboard.git \
  ~/Projects/agent-switchboard
cd ~/Projects/agent-switchboard
npm test

From the repository directory, register the server in both clients:

claude mcp add --scope user --transport stdio agent-switchboard -- \
  "$(command -v node)" "$PWD/server.mjs"

codex mcp add agent-switchboard -- \
  "$(command -v node)" "$PWD/server.mjs"

Both registrations use absolute paths. If you move the checkout or replace the Node.js executable, update those paths. Codex also accepts a [mcp_servers.agent-switchboard] entry in its configuration; see the Codex MCP documentation.

Reload the MCP connection when your client supports it, or open a session that loads the updated configuration. A saved registration doesn't establish that an already-running conversation has loaded the tools. Check for codex_list and claude_list in each client's tool catalog before using them.

Related MCP server: claude-intercom-mcp

Use it

Start by asking either agent to list the running Codex and Claude Code sessions. Choose the intended session from that list, then ask it to read the recent conversation or send a specific request. For example:

Find the Codex session working on this project, read its recent messages, and ask it to review the parser changes. Don't ask it to edit files.

Reads and messages use exact session UUIDs, so an agent must resolve an ambiguous name before sending. A message is a request to another agent, not a synchronous function call: inspect the receiving conversation for its response.

The following table describes the seven tools:

codex_list examines 30 recent saved sessions by default, with a maximum limit of 100; it isn't a complete inventory of every open task. Both read tools accept maxChars, and claude_send accepts receiptWaitMs. The MCP schemas describe their limits.

To check the MCP connection without asking an agent to call a tool, run the diagnostic client:

node mcp-client.mjs claude_list '{}'
node mcp-client.mjs codex_list '{"limit":10}'

This client starts only the MCP server, initializes it, retrieves the tool catalog, and calls the selected tool. It doesn't start a model session.

Permissions and delivery

Installing Switchboard gives the connected agent tools to read and direct other local sessions. Only install it in clients you trust with that access. The receiving agent can act with its own permissions, so sending a request can cause file changes, command execution, or external actions there. Switchboard does not provide cross-session permission isolation.

The adapters check local ownership, require private messaging sockets, read history without modifying it, and preserve the recipient's approval controls. Peer messages carry a Switchboard label, but that label is not authentication. Treat conversation content as untrusted input.

Claude can hold or refuse a message. transport-sent means the socket write finished, not that the agent accepted or completed the request. Similarly, owner-accepted from Codex is not proof of completion. After a timeout, inspect the conversation before retrying; the first message might already have arrived.

Compatibility

Live tests on September 11, 2026, demonstrated discovery, transcript reads, and bidirectional messaging between existing desktop sessions, including a second exchange after Claude became idle. Claude used its installed MCP tools; the Codex outbound path used the diagnostic MCP client. Those results do not establish compatibility with later application versions.

Codex idle start is implemented but lacks the live verification of steer. Session creation, cancellation, a Codex terminal adapter, and durable delivery receipts are not implemented. Claude terminal sessions that publish the same registry and inbox are discoverable by the adapter, but terminal messaging needs separate live acceptance. Recheck discovery, reads, and a bounded round trip after client upgrades.

For protocol details and the limits of the local checks, see the architecture and verification record.

Development

Run syntax checks and the local test suite:

npm run check
npm test

The tests use temporary sockets and fixture records. They do not message your running agents. Keep transcripts, session identifiers, peer keys, and local configuration out of commits; evidence/local/ is ignored for private test records.

License

Switchboard is available under the MIT license.