feat(skills): Add 'Use when / Don't use when' routing blocks (#14521)

* feat(skills): add 'Use when / Don't use when' blocks to skill descriptions

Based on OpenAI's Shell + Skills + Compaction best practices article.

Key changes:
- Added clear routing logic to skill descriptions
- Added negative examples to prevent misfires
- Added templates/examples to github skill
- Included Blake's specific setup notes for openhue

Skills updated:
- apple-reminders: Clarify vs Clawdbot cron
- github: Clarify vs local git operations
- imsg: Clarify vs other messaging channels
- openhue: Add device inventory, room layout
- tmux: Clarify vs exec tool
- weather: Add location defaults, format codes

Reference: https://developers.openai.com/blog/skills-shell-tips

* fix(skills): restore metadata and generic CLI examples

---------

Co-authored-by: Peter Steinberger <steipete@gmail.com>

skills/imsg/SKILL.md

@@ -1,6 +1,6 @@
 ---
 name: imsg
-description: iMessage/SMS CLI for listing chats, history, watch, and sending.
+description: iMessage/SMS CLI for listing chats, history, and sending messages via Messages.app.
 homepage: https://imsg.to
 metadata:
   {
@@ -23,52 +23,100 @@ metadata:
   }
 ---
 
-# imsg Actions
+# imsg
 
-## Overview
+Use `imsg` to read and send iMessage/SMS via macOS Messages.app.
 
-Use `imsg` to read and send Messages.app iMessage/SMS on macOS.
+## When to Use
 
-Requirements: Messages.app signed in, Full Disk Access for your terminal, and Automation permission to control Messages.app for sending.
+✅ **USE this skill when:**
 
-## Inputs to collect
+- User explicitly asks to send iMessage or SMS
+- Reading iMessage conversation history
+- Checking recent Messages.app chats
+- Sending to phone numbers or Apple IDs
 
-- Recipient handle (phone/email) for `send`
-- `chatId` for history/watch (from `imsg chats --limit 10 --json`)
-- `text` and optional `file` path for sends
+## When NOT to Use
 
-## Actions
+❌ **DON'T use this skill when:**
 
-### List chats
+- Telegram messages → use `message` tool with `channel:telegram`
+- Signal messages → use Signal channel if configured
+- WhatsApp messages → use WhatsApp channel if configured
+- Discord messages → use `message` tool 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 (Clawdbot 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
 
 ```bash
 imsg chats --limit 10 --json
 ```
 
-### Fetch chat history
+### View History
 
 ```bash
+# By chat ID
+imsg history --chat-id 1 --limit 20 --json
+
+# With attachments info
 imsg history --chat-id 1 --limit 20 --attachments --json
 ```
 
-### Watch a chat
+### Watch for New Messages
 
 ```bash
 imsg watch --chat-id 1 --attachments
 ```
 
-### Send a message
+### Send Messages
 
 ```bash
-imsg send --to "+14155551212" --text "hi" --file /path/pic.jpg
+# 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
 ```
 
-## Notes
+## Service Options
 
-- `--service imessage|sms|auto` controls delivery.
-- Confirm recipient + message before sending.
+- `--service imessage` — Force iMessage (requires recipient has iMessage)
+- `--service sms` — Force SMS (green bubble)
+- `--service auto` — Let Messages.app decide (default)
 
-## Ideas to try
+## Safety Rules
 
-- Use `imsg chats --limit 10 --json` to discover chat ids.
-- Watch a high-signal chat to stream incoming messages.
+1. **Always confirm recipient and message content** before sending
+2. **Never send to unknown numbers** without explicit user approval
+3. **Be careful with attachments** — confirm file path exists
+4. **Rate limit yourself** — don't spam
+
+## Example Workflow
+
+User: "Text mom that I'll be late"
+
+```bash
+# 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"
+```