claude-peers-mcp

Skill by ara.so — Daily 2026 Skills collection.

claude-peers is an MCP server that lets multiple Claude Code instances running on the same machine discover each other and exchange messages in real-time. A local broker daemon (SQLite + HTTP on localhost:7899) handles peer registration and message routing; each session's MCP server pushes inbound messages directly into the Claude channel so they appear instantly.

Installation

1. Clone and install dependencies

git clone https://github.com/louislva/claude-peers-mcp.git ~/claude-peers-mcp
cd ~/claude-peers-mcp
bun install

2. Register as a global MCP server

claude mcp add --scope user --transport stdio claude-peers -- bun ~/claude-peers-mcp/server.ts

Adjust the path if you cloned elsewhere.

3. Launch Claude Code with the channel enabled

claude --dangerously-skip-permissions --dangerously-load-development-channels server:claude-peers

Add a shell alias to avoid typing it every time:

# ~/.bashrc or ~/.zshrc
alias claudepeers='claude --dangerously-load-development-channels server:claude-peers'

The broker daemon starts automatically on first use. No manual daemon management needed.

Requirements

• Bun runtime
• Claude Code v2.1.80+
• claude.ai login (channels require it — API key auth does not work)

Architecture

                    ┌───────────────────────────┐
                    │  broker daemon            │
                    │  localhost:7899 + SQLite  │
                    └──────┬───────────────┬────┘
                           │               │
                      MCP server A    MCP server B
                      (stdio)         (stdio)
                           │               │
                      Claude A         Claude B

• Each Claude Code session spawns its own server.ts MCP process over stdio
• MCP servers register with the broker and poll every second
• Inbound messages are pushed via the claude/channel protocol for instant delivery
• The broker auto-cleans dead peers and is localhost-only

MCP Tools Reference

Tool	Description
list_peers	Discover other Claude Code instances; scope: machine, directory, or repo
send_message	Send a message to a peer by ID — delivered instantly via channel push
set_summary	Set a description of what this instance is working on
check_messages	Manually poll for messages (fallback without channel mode)

Example prompts to Claude

List all peers on this machine

Send a message to peer abc123: "what files are you editing right now?"

Set your summary to: "refactoring the authentication module"

Check for any new messages from peers

CLI Usage

Inspect and interact with the broker directly from the terminal:

cd ~/claude-peers-mcp

# Show broker status and all registered peers
bun cli.ts status

# List peers in a table
bun cli.ts peers

# Send a message into a specific Claude session
bun cli.ts send <peer-id> "your message here"

# Stop the broker daemon
bun cli.ts kill-broker

Configuration

Set these environment variables before starting Claude Code:

Variable	Default	Description
CLAUDE_PEERS_PORT	7899	Port the broker listens on
CLAUDE_PEERS_DB	~/.claude-peers.db	Path to the SQLite database
OPENAI_API_KEY	—	Enables auto-summary via gpt-4o-mini on startup

export CLAUDE_PEERS_PORT=7899
export CLAUDE_PEERS_DB=~/.claude-peers.db
export OPENAI_API_KEY=$OPENAI_API_KEY  # optional — enables auto-summary

Auto-Summary Feature

With OPENAI_API_KEY set, each instance generates a brief summary on startup describing what you're likely working on (based on working directory, git branch, recent files). Other peers see this in list_peers output. Without the key, Claude sets its own summary via set_summary.

Common Patterns

Cross-project coordination

Start two sessions in different project directories:

# Terminal 1 — in ~/projects/backend
claudepeers

# Terminal 2 — in ~/projects/frontend
claudepeers

Ask Claude in Terminal 1:

List peers scoped to machine, then ask the peer in the frontend project what API endpoints it needs

Scope-filtered peer discovery

List peers scoped to repo

Shows only instances running in the same git repository — useful when you have worktrees or split terminals on the same codebase.

Scripted message injection via CLI

# Inject a task into a running Claude session from a shell script
PEER_ID=$(bun ~/claude-peers-mcp/cli.ts peers | grep 'backend' | awk '{print $1}')
bun ~/claude-peers-mcp/cli.ts send "$PEER_ID" "run the test suite and report failures"

Polling fallback (no channel mode)

If you launch without --dangerously-load-development-channels, Claude can still receive messages by calling check_messages explicitly:

Check for any new peer messages

Troubleshooting

Broker not starting

# Check if something is already on port 7899
lsof -i :7899

# Kill a stuck broker and restart
bun ~/claude-peers-mcp/cli.ts kill-broker
# Then relaunch Claude Code

Peers not appearing in list_peers

• Ensure both sessions were started with --dangerously-load-development-channels server:claude-peers
• Confirm both use the same CLAUDE_PEERS_PORT (default 7899)
• Run bun cli.ts status to verify the broker sees both registrations

Messages not arriving instantly

• Channel push requires claude.ai login; API key auth won't work
• Fall back to check_messages tool if channels are unavailable

Auto-summary not generating

• Verify OPENAI_API_KEY is exported in the shell where Claude Code was launched: echo $OPENAI_API_KEY
• The feature uses gpt-4o-mini; confirm your key has access

Database issues

# Reset the database entirely (all peers/messages lost)
rm ~/.claude-peers.db
bun ~/claude-peers-mcp/cli.ts kill-broker

MCP server not found after registration

# Verify registration
claude mcp list

# Re-register if missing
claude mcp add --scope user --transport stdio claude-peers -- bun ~/claude-peers-mcp/server.ts