How do I install the Imsg skill?

Run npx skillmds@latest add understudy-ai/imsg 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 Imsg skill do?

iMessage/SMS CLI for listing chats, history, and sending messages via Messages.app. It is listed under Coding & Dev Tools on SkillMD.

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Imsg?

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.

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

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

Imsg by understudy-ai — Agent Skill

Name: Imsg
Author: understudy-ai

File contents

imsg

Use imsg to read and send iMessage/SMS via macOS Messages.app.

When to Use

✅ USE this skill when:

User explicitly asks to send iMessage or SMS
Reading iMessage conversation history
Checking recent Messages.app chats
Sending to phone numbers or Apple IDs

When NOT to Use

❌ DON'T use this skill when:

Telegram messages → use message_send with channel: "telegram"
Signal messages → use Signal channel if configured
WhatsApp messages → use WhatsApp channel if configured
Discord messages → use message_send with channel: "discord"
Slack messages → use slack skill
Group chat management (adding/removing members) → not supported
Bulk/mass messaging → always confirm with user first
Replying in current conversation → just reply normally (Understudy routes automatically)

Requirements

macOS with Messages.app signed in
Full Disk Access for terminal
Automation permission for Messages.app (for sending)

Common Commands

List Chats

imsg chats --limit 10 --json

View History

# By chat ID
imsg history --chat-id 1 --limit 20 --json

# With attachments info
imsg history --chat-id 1 --limit 20 --attachments --json

Watch for New Messages

imsg watch --chat-id 1 --attachments

Send Messages

# Text only
imsg send --to "+14155551212" --text "Hello!"

# With attachment
imsg send --to "+14155551212" --text "Check this out" --file /path/to/image.jpg

# Specify service
imsg send --to "+14155551212" --text "Hi" --service imessage
imsg send --to "+14155551212" --text "Hi" --service sms

Service Options

--service imessage — Force iMessage (requires recipient has iMessage)
--service sms — Force SMS (green bubble)
--service auto — Let Messages.app decide (default)

Safety Rules

Always confirm recipient and message content before sending
Never send to unknown numbers without explicit user approval
Be careful with attachments — confirm file path exists
Rate limit yourself — don't spam

Example Workflow

User: "Text mom that I'll be late"

# 1. Find mom's chat
imsg chats --limit 20 --json | jq '.[] | select(.displayName | contains("Mom"))'

# 2. Confirm with user
# "Found Mom at +1555123456. Send 'I'll be late' via iMessage?"

# 3. Send after confirmation
imsg send --to "+1555123456" --text "I'll be late"

---name: imsgdescription: iMessage/SMS CLI for listing chats, history, and sending messages via Messages.app.---# imsgUse `imsg` to read and send iMessage/SMS via macOS Messages.app.## When to Use✅ **USE this skill when:**- User explicitly asks to send iMessage or SMS- Reading iMessage conversation history- Checking recent Messages.app chats- Sending to phone numbers or Apple IDs## When NOT to Use❌ **DON'T use this skill when:**- Telegram messages → use `message_send` with `channel: "telegram"`- Signal messages → use Signal channel if configured- WhatsApp messages → use WhatsApp channel if configured- Discord messages → use `message_send` with `channel: "discord"`- Slack messages → use `slack` skill- Group chat management (adding/removing members) → not supported- Bulk/mass messaging → always confirm with user first- Replying in current conversation → just reply normally (Understudy routes automatically)## Requirements- macOS with Messages.app signed in- Full Disk Access for terminal- Automation permission for Messages.app (for sending)## Common Commands### List Chats```bashimsg chats --limit 10 --json```### View History```bash# By chat IDimsg history --chat-id 1 --limit 20 --json# With attachments infoimsg history --chat-id 1 --limit 20 --attachments --json```### Watch for New Messages```bashimsg watch --chat-id 1 --attachments```### Send Messages```bash# Text onlyimsg send --to "+14155551212" --text "Hello!"# With attachmentimsg send --to "+14155551212" --text "Check this out" --file /path/to/image.jpg# Specify serviceimsg send --to "+14155551212" --text "Hi" --service imessageimsg send --to "+14155551212" --text "Hi" --service sms```## Service Options- `--service imessage` — Force iMessage (requires recipient has iMessage)- `--service sms` — Force SMS (green bubble)- `--service auto` — Let Messages.app decide (default)## Safety Rules1. **Always confirm recipient and message content** before sending2. **Never send to unknown numbers** without explicit user approval3. **Be careful with attachments** — confirm file path exists4. **Rate limit yourself** — don't spam## Example WorkflowUser: "Text mom that I'll be late"```bash# 1. Find mom's chatimsg chats --limit 20 --json | jq '.[] | select(.displayName | contains("Mom"))'# 2. Confirm with user# "Found Mom at +1555123456. Send 'I'll be late' via iMessage?"# 3. Send after confirmationimsg send --to "+1555123456" --text "I'll be late"```

Frequently asked questions

Imsg