codex-peers-mcp

Peer discovery + messaging for Codex sessions on one machine.

Isolation tip: on shared hosts, set a unique CODEX_PEERS_NAMESPACE (and optionally CODEX_PEERS_TOKEN) to prevent cross-user message mixing.

Features

• whoami: get current peer id/context

• list_peers: find other Codex sessions (machine, directory, repo scopes)

• send_message: direct message by peer id

• send_message_by_filter: message a peer by repo_name / cwd_contains / summary_contains

• set_summary: publish what this session is working on

• check_messages: read unread inbox

Related MCP server: slm-mesh

Architecture

• Local broker daemon on localhost:${CODEX_PEERS_PORT:-7899}

• SQLite backing store (${CODEX_PEERS_DB:-~/.codex-peers.db})

• MCP stdio server per Codex session

Install

cd ~/clawd/projects/codex-peers-mcp
bun install

Run broker manually (optional)

bun run src/broker.ts

The MCP server auto-starts the broker if it is not running.

Register with Codex MCP

Add this server to Codex MCP config (example command shape; adapt to your codex mcp add flow):

codex mcp add codex-peers -- bun ~/clawd/projects/codex-peers-mcp/src/server.ts

Test quickly

Option A — one-command smoke test (recommended for new users)

cd ~/clawd/projects/codex-peers-mcp
bash scripts/smoke.sh

This runs a self-loop MCP validation in Codex:

• whoami

• set_summary

• send_message (to self)

• check_messages

You should see JSON output followed by smoke: PASS.

Option B — manual two-session test

1. Start Codex session A and B with this MCP server enabled.

2. In B: call set_summary (e.g. receiver-smoke).

3. In A: call send_message_by_filter with summary_contains=receiver-smoke.

4. In B: call check_messages.

CLI

bun run src/cli.ts status
bun run src/cli.ts peers
bun run src/cli.ts send <peer_id> "hello"

Auth caveat (important)

If Codex says quota exceeded unexpectedly, verify auth mode:

codex login status

If it says API key mode, switch back to ChatGPT OAuth for this workflow:

codex logout
unset OPENAI_API_KEY
codex login

Env vars

• CODEX_PEERS_PORT (default 7899)

• CODEX_PEERS_DB (default ~/.codex-peers.db)

• CODEX_PEERS_NAMESPACE (default default) — use a unique namespace to isolate teams/users on shared hosts

• CODEX_PEERS_TOKEN (optional) — when set, broker requires x-codex-peers-token on non-health routes

• CODEX_PEER_ID (optional override for generated peer id)

Validation scripts

bash scripts/test-broker-routes.sh
bash scripts/smoke.sh