How do I install the Agentmail skill?

Run npx skillmds@latest add diegosouzapw/agentmail in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

What does the Agentmail skill do?

Inter-agent communication for tmux sessions. Send and receive messages between AI agents. It is listed under AI & ML, Integrations & APIs on SkillMD.

Is Agentmail safe to use?

SkillMD's automated safety review verdict for this skill is PASS. Independent scanners report: SkillSpector: PASS, Skill Scanner: PASS. Capability flags: docs only. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Agentmail?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Agentmail free to use?

Yes. Installing skills from SkillMD is free. This skill is licensed under MIT.

Who published Agentmail?

diegosouzapw (@diegosouzapw) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Agentmail by diegosouzapw — Agent Skill

Name: Agentmail
Rating: 4.666666666666667 (3 reviews)
Author: diegosouzapw

File contents

AgentMail Skill

AgentMail enables communication between AI agents running in different tmux windows through a simple file-based mail system.

Overview

AgentMail is a CLI tool for inter-agent communication within tmux sessions. Messages are stored in .agentmail/mailboxes/ as JSONL files, providing persistent, file-locked message queues for each agent.

Prerequisites

Must be running inside a tmux session
AgentMail CLI must be installed and available in PATH
Messages stored in .agentmail/ directory

Core Commands

Send a Message

agentmail send <recipient> "<message>"

Send a message to another agent. The recipient must be a valid tmux window name.

Examples:

agentmail send agent2 "Can you review the changes in src/api?"
agentmail send -r worker -m "Task completed"
echo "Build succeeded" | agentmail send agent2

Receive Messages

agentmail receive

Read the oldest unread message from your mailbox. Messages are delivered in FIFO order and marked as read after display.

List Recipients

agentmail recipients

List all tmux windows that can receive messages. Your current window is marked with [you].

Set Status

agentmail status <ready|work|offline>

Set your availability status:

ready - Available to receive messages and notifications
work - Busy working (suppresses notifications)
offline - Not available (suppresses notifications)

Workflow

Checking for Messages

Run agentmail receive to check for new messages
If a message is available, read and process it
Optionally reply using agentmail send

Sending Messages

Run agentmail recipients to see available agents
Send your message: agentmail send <recipient> "<message>"
Confirm delivery via the returned message ID

Status Management

The plugin automatically manages your status:

Session start: Status set to ready
Session end: Status set to offline
End of turn (Stop): Status set to ready, checks for new messages

Message Format

Messages include:

ID: Unique 8-character base62 identifier (a-z, A-Z, 0-9)
From: Sender's tmux window name
To: Recipient's tmux window name
Content: Message body

Best Practices

Check messages regularly - Use agentmail receive to stay informed
Keep messages concise - Focus on actionable information
Include context - Reference files, line numbers, or specific details
Respond promptly - Other agents may be waiting for your input
Use status appropriately - Set work when focusing on complex tasks

Integration with Claude Code

This plugin integrates with Claude Code hooks:

SessionStart: Automatically sets status to ready and runs onboarding
SessionEnd: Automatically sets status to offline
Stop: Sets status to ready and checks for new messages

The hooks ensure agents are properly registered and can receive notifications from the mailman daemon.

Troubleshooting

"Not in a tmux session"

AgentMail requires tmux. Start a tmux session first.

"Recipient not found"

The recipient window doesn't exist. Check available windows with agentmail recipients.

"No unread messages"

Your mailbox is empty. Other agents haven't sent you messages yet.

Messages not being delivered

Ensure the mailman daemon is running: agentmail mailman --daemon

---name: agentmaildescription: Inter-agent communication for tmux sessions. Send and receive messages between AI agents.license: MIT---# AgentMail SkillAgentMail enables communication between AI agents running in different tmux windows through a simple file-based mail system.## OverviewAgentMail is a CLI tool for inter-agent communication within tmux sessions. Messages are stored in `.agentmail/mailboxes/` as JSONL files, providing persistent, file-locked message queues for each agent.## Prerequisites- Must be running inside a tmux session- AgentMail CLI must be installed and available in PATH- Messages stored in `.agentmail/` directory## Core Commands### Send a Message```bashagentmail send <recipient> "<message>"```Send a message to another agent. The recipient must be a valid tmux window name.**Examples:**```bashagentmail send agent2 "Can you review the changes in src/api?"agentmail send -r worker -m "Task completed"echo "Build succeeded" | agentmail send agent2```### Receive Messages```bashagentmail receive```Read the oldest unread message from your mailbox. Messages are delivered in FIFO order and marked as read after display.### List Recipients```bashagentmail recipients```List all tmux windows that can receive messages. Your current window is marked with `[you]`.### Set Status```bashagentmail status <ready|work|offline>```Set your availability status:- `ready` - Available to receive messages and notifications- `work` - Busy working (suppresses notifications)- `offline` - Not available (suppresses notifications)## Workflow### Checking for Messages1. Run `agentmail receive` to check for new messages2. If a message is available, read and process it3. Optionally reply using `agentmail send`### Sending Messages1. Run `agentmail recipients` to see available agents2. Send your message: `agentmail send <recipient> "<message>"`3. Confirm delivery via the returned message ID### Status ManagementThe plugin automatically manages your status:- **Session start**: Status set to `ready`- **Session end**: Status set to `offline`- **End of turn (Stop)**: Status set to `ready`, checks for new messages## Message FormatMessages include:- **ID**: Unique 8-character base62 identifier (a-z, A-Z, 0-9)- **From**: Sender's tmux window name- **To**: Recipient's tmux window name- **Content**: Message body## Best Practices1. **Check messages regularly** - Use `agentmail receive` to stay informed2. **Keep messages concise** - Focus on actionable information3. **Include context** - Reference files, line numbers, or specific details4. **Respond promptly** - Other agents may be waiting for your input5. **Use status appropriately** - Set `work` when focusing on complex tasks## Integration with Claude CodeThis plugin integrates with Claude Code hooks:- **SessionStart**: Automatically sets status to `ready` and runs onboarding- **SessionEnd**: Automatically sets status to `offline`- **Stop**: Sets status to `ready` and checks for new messagesThe hooks ensure agents are properly registered and can receive notifications from the mailman daemon.## Troubleshooting### "Not in a tmux session"AgentMail requires tmux. Start a tmux session first.### "Recipient not found"The recipient window doesn't exist. Check available windows with `agentmail recipients`.### "No unread messages"Your mailbox is empty. Other agents haven't sent you messages yet.### Messages not being deliveredEnsure the mailman daemon is running: `agentmail mailman --daemon`

Frequently asked questions

Agentmail