beads/docs/AGENT_MAIL.md

Agent Mail Integration Guide

Status: Optional Enhancement
Minimum bd Version: 0.21.0
Related ADR: 002-agent-mail-integration.md

Overview

MCP Agent Mail provides real-time coordination for multi-agent beads workflows, reducing latency from 2-5 seconds (git sync) to <100ms (HTTP API) and preventing work collisions through file reservations.

Key Benefits:

• 20-50x latency reduction: <100ms vs 2000-5000ms for status updates
• Collision prevention: Exclusive file reservations prevent duplicate work
• Lightweight: <50MB memory, simple HTTP API
• 100% optional: Git-only mode works identically without it

Quick Start

Prerequisites

• Python 3.11+
• bd 0.21.0+
• Multi-agent workflow (2+ AI agents working on same repository)

Installation

# Install Agent Mail server
git clone https://github.com/Dicklesworthstone/mcp_agent_mail.git
cd mcp_agent_mail
python3 -m venv .venv
source .venv/bin/activate  # Windows: .venv\Scripts\activate
pip install -e .

# Start server
python -m mcp_agent_mail.cli serve-http
# Server runs on http://127.0.0.1:8765

Configuration

Enable Agent Mail by setting environment variables before running bd commands:

# Agent 1
export BEADS_AGENT_MAIL_URL=http://127.0.0.1:8765
export BEADS_AGENT_NAME=assistant-alpha
export BEADS_PROJECT_ID=my-project

# Agent 2
export BEADS_AGENT_MAIL_URL=http://127.0.0.1:8765
export BEADS_AGENT_NAME=assistant-beta
export BEADS_PROJECT_ID=my-project

# Now run bd commands normally
bd ready
bd update bd-42 --status in_progress

All configuration is via environment variables - no changes to .beads/ or git required.

Verification

# Check if Agent Mail is active
bd info --json | grep agent_mail

# View reservations in web UI
open http://127.0.0.1:8765/mail

# Test collision prevention
# Terminal 1 (Agent A):
bd update bd-123 --status in_progress

# Terminal 2 (Agent B):
bd update bd-123 --status in_progress
# Expected: Error - bd-123 reserved by assistant-alpha

How It Works

Architecture

┌─────────────────────────────────────────────┐
│ bd (Beads CLI)                              │
│                                             │
│  ┌─────────────┐      ┌─────────────────┐  │
│  │ Git Sync    │      │ Agent Mail      │  │
│  │ (required)  │      │ (optional)      │  │
│  │             │      │                 │  │
│  │ - Export    │      │ - Reservations  │  │
│  │ - Import    │      │ - Notifications │  │
│  │ - Commit    │      │ - Status updates│  │
│  │ - Push/Pull │      │                 │  │
│  └─────────────┘      └─────────────────┘  │
│         │                      │            │
└─────────┼──────────────────────┼────────────┘
          │                      │
          ▼                      ▼
  ┌──────────────┐      ┌──────────────┐
  │ .beads/      │      │ Agent Mail   │
  │ issues.jsonl │      │ Server       │
  │ (git)        │      │ (HTTP)       │
  └──────────────┘      └──────────────┘

Git remains the source of truth. Agent Mail provides ephemeral coordination state only.

Coordination Flow

Without Agent Mail (git-only):

Agent A: bd update bd-123 --status in_progress
  ↓ (30s debounce)
  ↓ export to JSONL
  ↓ git commit + push (1-2s)
  ↓ 
Agent B: git pull (1-2s)
  ↓ import from JSONL
  ↓ sees bd-123 is taken (TOO LATE - work already started!)

Total latency: 2000-5000ms
Risk: Both agents work on same issue

With Agent Mail:

Agent A: bd update bd-123 --status in_progress
  ↓ 
  ├─ Agent Mail: POST /api/reservations (5ms)
  │  └─ Reserve bd-123 for Agent A
  ├─ Local: Update .beads/beads.db
  └─ Background: Export to JSONL (30s debounce)
  
Agent B: bd update bd-123 --status in_progress
  ↓
  └─ Agent Mail: POST /api/reservations (5ms)
     └─ HTTP 409 Conflict: "bd-123 reserved by Agent A"
     └─ bd exits with clear error

Total latency: <100ms
Risk: Zero - collision prevented at reservation layer

Integration Points

Agent Mail integrates at 4 key points in the bd workflow:

1. Issue Reservation (bd update --status in_progress)

   • Check if issue already reserved
   • Create reservation if available
   • Error 409 if conflict

2. Issue Release (bd close)

   • Release reservation automatically
   • Notify other agents (optional)

3. Ready Work Query (bd ready)

   • Filter out reserved issues (future enhancement)
   • Show only truly available work

4. Status Updates (bd update --priority, etc.)

   • No reservation required for non-status changes
   • Graceful degradation if server unavailable

Configuration Reference

Environment Variables

Variable	Required	Default	Description
BEADS_AGENT_MAIL_URL	Yes	None	Agent Mail server URL (e.g., http://127.0.0.1:8765)
BEADS_AGENT_NAME	Yes	None	Unique agent identifier (e.g., assistant-alpha)
BEADS_PROJECT_ID	Yes	None	Project namespace (e.g., my-project)
BEADS_AGENT_MAIL_TOKEN	No	None	Bearer token for authentication (future)

Example Configurations

Local Development (Single Machine):

# ~/.bashrc or ~/.zshrc
export BEADS_AGENT_MAIL_URL=http://127.0.0.1:8765
export BEADS_AGENT_NAME=$(whoami)-$(hostname)
export BEADS_PROJECT_ID=$(basename $(pwd))

Multi-Machine Setup:

# Machine 1 (runs server)
export BEADS_AGENT_MAIL_URL=http://192.168.1.100:8765
export BEADS_AGENT_NAME=dev-machine-1
export BEADS_PROJECT_ID=beads

# Machine 2 (client only)
export BEADS_AGENT_MAIL_URL=http://192.168.1.100:8765
export BEADS_AGENT_NAME=dev-machine-2
export BEADS_PROJECT_ID=beads

Docker Compose:

services:
  agent-mail:
    image: ghcr.io/dicklesworthstone/mcp_agent_mail:latest
    ports:
      - "8765:8765"
    
  agent-1:
    image: my-beads-agent
    environment:
      BEADS_AGENT_MAIL_URL: http://agent-mail:8765
      BEADS_AGENT_NAME: worker-1
      BEADS_PROJECT_ID: my-project

When to Use Agent Mail

✅ Use Agent Mail When:

1. Multiple AI agents working on the same repository simultaneously
2. Frequent status updates (multiple agents claiming/releasing work)
3. Collision-sensitive workflows (duplicate work is expensive)
4. Real-time coordination needed (latency matters)
5. CI/CD integration (agents triggered by webhooks/events)

Example Scenario:

• Team has 3 AI agents (Claude, GPT-4, Gemini)
• Agents pull from work queue every 5 minutes
• Repository has 50+ open issues
• Duplicate work costs 30+ minutes to resolve

❌ Skip Agent Mail When:

1. Single agent workflows (no collision risk)
2. Infrequent updates (once per day/week)
3. Git-only infrastructure (no external services allowed)
4. Offline workflows (no network connectivity)
5. Low issue volume (<10 open issues)

Example Scenario:

• Solo developer using beads for personal task tracking
• Updates happen once per session
• No concurrent work
• Simplicity over latency

Graceful Degradation

Agent Mail failure NEVER breaks beads. If the server is unavailable:

1. bd logs a warning: Agent Mail unavailable, falling back to git-only mode
2. All operations proceed normally
3. Git sync handles coordination (with higher latency)
4. No errors, no crashes

Test graceful degradation:

# Stop Agent Mail server
pkill -f "mcp_agent_mail.cli"

# bd commands work identically
bd ready  # Success
bd update bd-42 --status in_progress  # Success (git-only mode)

Automatic fallback conditions:

• Server not responding (connection refused)
• Server returns 500+ errors
• Network timeout (>5s)
• Invalid/missing environment variables

Multi-Machine Deployment

Centralized Server Pattern (Recommended)

┌─────────────┐     ┌─────────────┐     ┌─────────────┐
│  Agent A    │────▶│ Agent Mail  │◀────│  Agent B    │
│ (Machine 1) │     │   Server    │     │ (Machine 2) │
└─────────────┘     │ (Machine 3) │     └─────────────┘
                    └─────────────┘
                           │
                           ▼
                    ┌─────────────┐
                    │ PostgreSQL  │ (optional)
                    │  Storage    │
                    └─────────────┘

Steps:

1. Deploy Agent Mail on dedicated server/container
2. Configure firewall to allow port 8765 from agent machines
3. Set BEADS_AGENT_MAIL_URL to server IP on all agents
4. (Optional) Configure PostgreSQL backend for persistence

Peer-to-Peer Pattern (Advanced)

┌─────────────┐     ┌─────────────┐
│  Agent A    │────▶│  Agent B    │
│ + Server    │     │ + Server    │
└─────────────┘     └─────────────┘
       │                   │
       └─────────┬─────────┘
                 ▼
          ┌─────────────┐
          │ Shared DB   │ (e.g., Redis)
          └─────────────┘

Use case: High-availability setups where server can't be single point of failure.

Troubleshooting

Issue: "Agent Mail unavailable" warnings

Symptoms:

WARN Agent Mail unavailable, falling back to git-only mode

Solutions:

1. Check server is running: curl http://127.0.0.1:8765/health
2. Verify BEADS_AGENT_MAIL_URL is set correctly
3. Check firewall allows connections to port 8765
4. Review server logs: tail -f ~/.mcp_agent_mail/logs/server.log

Issue: "Reservation conflict" errors

Symptoms:

Error: bd-123 already reserved by assistant-alpha

Solutions:

1. Expected behavior - another agent claimed the issue first
2. Find different work: bd ready
3. If reservation is stale (agent crashed), release manually:

   curl -X DELETE http://127.0.0.1:8765/api/reservations/bd-123
   

4. Configure reservation TTL to auto-expire stale locks (future)

Issue: Reservations persist after agent crashes

Symptoms:

• Agent crashes mid-work
• Reservation not released
• Other agents can't claim the issue

Solutions:

1. Manual release via web UI: http://127.0.0.1:8765/mail
2. API release: curl -X DELETE http://127.0.0.1:8765/api/reservations/<issue-id>
3. Restart server (clears all ephemeral state): pkill -f mcp_agent_mail; python -m mcp_agent_mail.cli serve-http
4. Future: Configure TTL to auto-expire (not yet implemented)

Issue: Two agents have different project IDs

Symptoms:

• Agents don't see each other's reservations
• Collisions still happen

Solutions:

1. Ensure all agents use same BEADS_PROJECT_ID
2. Check environment: echo $BEADS_PROJECT_ID
3. Set globally in shell profile:

   # ~/.bashrc
   export BEADS_PROJECT_ID=my-project
   

Issue: Server uses too much memory

Symptoms:

• Agent Mail process grows to 100+ MB
• Server becomes slow

Solutions:

1. Normal for in-memory mode (<50MB baseline + reservation data)
2. Use PostgreSQL backend for large-scale deployments
3. Configure reservation expiry to prevent unbounded growth
4. Restart server periodically (ephemeral state is OK to lose)

Migration from Git-Only Mode

Good news: Zero migration required! Agent Mail is purely additive.

Step 1: Test with Single Agent

# Start server
python -m mcp_agent_mail.cli serve-http

# Configure one agent
export BEADS_AGENT_MAIL_URL=http://127.0.0.1:8765
export BEADS_AGENT_NAME=test-agent
export BEADS_PROJECT_ID=test

# Run normal workflow
bd ready
bd update bd-42 --status in_progress
bd close bd-42 "Done"

# Verify in web UI
open http://127.0.0.1:8765/mail

Step 2: Add Second Agent

# In separate terminal/machine
export BEADS_AGENT_MAIL_URL=http://127.0.0.1:8765
export BEADS_AGENT_NAME=test-agent-2
export BEADS_PROJECT_ID=test

# Try claiming same issue (should fail)
bd update bd-42 --status in_progress
# Expected: Error - reservation conflict

Step 3: Roll Out to Production

1. Deploy Agent Mail server to production environment
2. Add environment variables to agent deployment configs
3. Monitor logs for "Agent Mail unavailable" warnings
4. Gradually enable for all agents

Rollback Plan

Simply unset environment variables - agents immediately fall back to git-only mode:

unset BEADS_AGENT_MAIL_URL
unset BEADS_AGENT_NAME
unset BEADS_PROJECT_ID

# bd works identically without Agent Mail
bd ready

FAQ

Q: Do I need Agent Mail for single-agent workflows?

A: No. Agent Mail is only useful for multi-agent coordination. Single agents get no benefit from it.

Q: Can I use Agent Mail with the MCP server (beads-mcp)?

A: Yes! Set the environment variables before starting beads-mcp, and it will use Agent Mail for all operations.

Q: What happens if Agent Mail and git get out of sync?

A: Git is the source of truth. If Agent Mail has stale reservation data, worst case is a 409 error. Agent can manually release and retry.

Q: Does Agent Mail require changes to .beads/ or git?

A: No. Agent Mail is 100% external. No changes to database schema, JSONL format, or git workflow.

Q: Can I use Agent Mail for multiple projects on the same server?

A: Yes. Set different BEADS_PROJECT_ID for each project. Agent Mail provides namespace isolation.

Q: Is Agent Mail required for beads 1.0?

A: No. Agent Mail is an optional enhancement. Git-only mode is fully supported indefinitely.

Q: How does Agent Mail handle authentication?

A: Currently, no authentication (local network only). Bearer token support planned for future release.

Q: Can I self-host Agent Mail on corporate infrastructure?

A: Yes. Agent Mail is open source (MIT license) and can be deployed anywhere Python runs.

Q: What's the performance impact of Agent Mail?

A: ~5ms overhead per reservation API call. Negligible compared to 2000-5000ms git sync.

Q: Does Agent Mail work with protected branches?

A: Yes. Agent Mail operates independently of git workflow. Use with bd config set sync.branch beads-metadata as normal.

Advanced Topics

Custom Reservation TTL

# Future feature (not yet implemented)
export BEADS_RESERVATION_TTL=3600  # 1 hour in seconds

PostgreSQL Backend

# For production deployments with persistence
export AGENT_MAIL_DB_URL=postgresql://user:pass@localhost/agentmail
python -m mcp_agent_mail.cli serve-http

Monitoring & Observability

# Server exposes Prometheus metrics (future)
curl http://127.0.0.1:8765/metrics

# Health check
curl http://127.0.0.1:8765/health

Integration with CI/CD

# GitHub Actions example
jobs:
  agent-workflow:
    runs-on: ubuntu-latest
    services:
      agent-mail:
        image: ghcr.io/dicklesworthstone/mcp_agent_mail:latest
        ports:
          - 8765:8765
    env:
      BEADS_AGENT_MAIL_URL: http://localhost:8765
      BEADS_AGENT_NAME: github-actions-${{ github.run_id }}
      BEADS_PROJECT_ID: ${{ github.repository }}
    steps:
      - run: bd ready | head -1 | xargs -I {} bd update {} --status in_progress

Resources

• ADR 002: Agent Mail Integration
• Agent Mail Repository
• Python Agent Example

Contributing

Found a bug or want to improve Agent Mail integration? See:

• CONTRIBUTING.md for beads contribution guidelines
• Agent Mail Issues for server-side issues

License

Beads: Apache 2.0
MCP Agent Mail: MIT