When should I use Agent Mail instead of git worktrees?

Use Agent Mail when multiple agents need to work on the same branch simultaneously. Git worktrees isolate agents completely, which prevents conflicts but also prevents coordination. Agent Mail gives agents shared visibility into who's working on what, advisory file reservations, and threaded messaging — enabling real collaboration rather than just isolation.

Does Agent Mail work with Claude Code, Codex, and Gemini?

Yes. Running 'am' auto-detects all installed coding agents (Claude Code, Codex CLI, Gemini CLI, GitHub Copilot CLI) and configures their MCP connections. Agents communicate through the MCP standard, so any MCP-capable coding agent can use Agent Mail.

How does the pre-commit guard work?

The mcp-agent-mail-guard binary installs as a Git pre-commit hook. When you commit, it checks whether any committed files overlap with another agent's active reservations. If they do, the commit is blocked with a clear conflict message. You can bypass it with AGENT_MAIL_BYPASS=1 or set AGENT_MAIL_GUARD_MODE=warn for warning-only mode.

How does Agent Mail prevent message history from filling up context windows?

Messages are stored externally in SQLite (for query speed) and Git (for audit trails). Agents only fetch what they need via fetch_inbox or search_messages. The full conversation history lives outside agent context windows, so agents can coordinate across thousands of messages without consuming tokens.

Can Agent Mail coordinate across multiple repositories?

Yes. The product bus links multiple repositories under a single umbrella. Agents in different repos can discover each other via contact handshakes, exchange messages across project boundaries, and search across all linked projects.

What happens when a reservation expires?

Reservations have a TTL (default 3600 seconds). When the TTL expires, the reservation is automatically cleaned up and other agents can reserve the same files. Agents can renew reservations before expiration to extend their work window.

How is Agent Mail different from the Python version?

The Rust rewrite is a ground-up reimplementation that eliminates the Python version's scalability bottlenecks: Git lock contention, SQLite pool exhaustion, and GIL limitations. The Rust version adds hybrid search (V3), a 15-screen TUI, robot mode CLI, build slot management, and passes a 10-scenario stress gauntlet including 30-agent pipelines and sustained 49 RPS workloads.

How do I monitor what my agents are doing?

Three ways: (1) The 15-screen TUI provides real-time dashboards, message browsing, thread exploration, and system health monitoring. (2) The web UI at localhost:8765/mail gives browser-based oversight with inbox, search, and the Human Overseer compose form. (3) Robot mode (am robot status) provides machine-readable output for automation.

What is the stress gauntlet?

A 10-scenario test suite that validates production readiness: 30-agent message pipelines, 10-project concurrent operations, commit coalescer efficiency, stale Git lock recovery, mixed reservation + messaging loads, connection pool exhaustion recovery, sustained 30-second throughput, thundering herd handling, and inbox reads during message storms. All scenarios pass with zero errors.

Get Started

Install MCP Agent Mail, start the server, and launch your first reservation-aware multi-agent workflow.

Step 1

Install

Install the binary with the recommended one-liner.

$curl -fsSL "https://raw.githubusercontent.com/Dicklesworthstone/mcp_agent_mail_rust/main/install.sh?$(date +%s)" | bash

Step 2

Run Your First Coordination Flow

Start `am`, register an agent, reserve files, and coordinate through threaded messages.

quickstart.md

01# 1) Start MCP Agent Mail server + TUI02am03 04# 2) Bootstrap session context in one call05macro_start_session(06  project_key="/abs/path/to/repo",07  program="codex-cli",08  model="gpt-5"09)10 11# 3) Reserve files before editing12file_reservation_paths(13  project_key,14  agent_name,15  ["src/**"],16  ttl_seconds=3600,17  exclusive=true18)19 20# 4) Coordinate through threaded messages21send_message(22  project_key,23  sender_name="GreenCastle",24  to=["BlueLake"],25  subject="Starting auth refactor",26  thread_id="FEAT-123",27  ack_required=true,28  body_md="I have reservations on src/auth/**; taking login + token rotation."29)30fetch_inbox(project_key, agent_name)31acknowledge_message(project_key, agent_name, message_id)

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Step 3

Configure MCP Client

Add the MCP server entry once; then your agent CLI can call Agent Mail tools directly.

.mcp.json / .codex/config.json

01{02  "mcpServers": {03    "agent-mail": {04      "command": "mcp-agent-mail",05      "args": []06    }07  }08}

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Core Patterns

Three Pillars

The foundations of safe multi-agent execution at scale.

Scoped Agent Identity

Project-scoped identities, thread continuity, and explicit inbox semantics keep parallel agents coordinated instead of colliding.

Reservation Guardrails

Advisory file reservations plus optional guard enforcement make ownership visible before edits and safer at commit time.

Auditable Workflows

Messages, acknowledgements, and search traces are queryable in SQLite and preserved in a Git-auditable archive.

FAQ

Common Questions

Answers to common setup and operations questions for MCP Agent Mail.

Do I need to configure every agent manually?

No. Running `am` auto-detects common coding agents and can bootstrap MCP connectivity. Manual config snippets are still available for Claude Code, Codex CLI, and Gemini CLI when needed.

What is the fastest way to start on a repository?

Start `am`, then use `macro_start_session` to register the agent, fetch inbox context, and begin reservation-aware work in one step.

Are file reservations mandatory locks?

They are advisory coordination primitives with conflict visibility, plus optional pre-commit enforcement if you install the guard integration.

How does Agent Mail avoid losing message history?

Messages are recorded in SQLite for query speed and exported into a Git-auditable archive for durable, reviewable history.

Can this work across multiple repos/projects?

Yes. Product-level search, inbox aggregation, and cross-project contact workflows are built in for multi-repo coordination.

Read the System Architecture Explore Interactive Demos