Send notifications to Slack channels with support for threads, file uploads, message updates, and user group mentions. TRIGGER when: sending messages, uploading files, or updating messages in Slack channels. DO NOT TRIGGER when: setting up Slack integration (use Dev10x:slack-setup), or posting review requests (use Dev10x:slack-review-request).
Announce: "Using Dev10x:slack to send a Slack notification."
This skill follows references/task-orchestration.md patterns.
Create a task at invocation, mark completed when done:
REQUIRED: Create a task at invocation. Execute at startup:
TaskCreate(subject="Send Slack notification", activeForm="Sending notification")Mark completed when done: TaskUpdate(taskId, status="completed")
Post messages, upload files, reply in threads, update or delete messages, and send self-DM reminders — all from Claude Code. The script resolves user group mentions automatically from your config.
If no Slack token is found, walk the user through setup using AskUserQuestion:
Step 1 — Token storage method:
| Option | Pros | Cons |
|---|---|---|
| System keyring (recommended) | Secure, persists across sessions | Requires secret-tool |
SLACK_TOKEN env var | Simple, works everywhere | Must set per-session |
| Config file token | Always available | Plaintext on disk |
For keyring (recommended):
secret-tool store --label="Slack Bot Token" service slack key bot_token
For env var: add export SLACK_TOKEN=xoxb-... to shell profile.
Step 2 — User token vs bot token:
xoxb- (bot token): Posts as a named bot. Requires the app to be
added to each channel. Set bot_username in config.xoxp- (user token): Posts as yourself. No username override.
Broader permissions but tied to your account.The script auto-detects the token type from its prefix.
Create ~/.claude/memory/Dev10x/slack-config.yaml:
# Your Slack user ID (for --remind self-DMs)
self_user_id: U040B2ES3N2
# Display name when posting with a bot token (xoxb-)
bot_username: Claude AI
# User group mention resolution (@name → <!subteam^ID>)
user_groups:
"@dev-team": "<!subteam^S0123456789>"
"@qa-team": "<!subteam^S9876543210>"
All fields are optional. The script works without a config file — user group mentions and self-DMs just won't resolve.
${CLAUDE_PLUGIN_ROOT}/skills/slack/slack-notify.py \
--channel CHANNEL_ID \
--message "Your message here"
${CLAUDE_PLUGIN_ROOT}/skills/slack/slack-notify.py \
--channel CHANNEL_ID \
--thread-ts 1770113637.855309 \
--message "Thread reply"
Extracting thread info from a Slack URL:
https://WORKSPACE.slack.com/archives/<CHANNEL>/p<TS>. before the last 6 digits of the timestamp
(e.g., p1770113637855309 → 1770113637.855309)${CLAUDE_PLUGIN_ROOT}/skills/slack/slack-notify.py \
--channel CHANNEL_ID \
--files screenshot.png report.pdf \
--message "Optional comment"
${CLAUDE_PLUGIN_ROOT}/skills/slack/slack-notify.py \
--channel CHANNEL_ID \
--update MESSAGE_TS \
--message "Revised content"
${CLAUDE_PLUGIN_ROOT}/skills/slack/slack-notify.py \
--channel CHANNEL_ID \
--delete MESSAGE_TS
${CLAUDE_PLUGIN_ROOT}/skills/slack/slack-notify.py \
--delete-file FILE_ID
Does not require --channel. Use the file ID returned by --files
upload or visible in Slack URLs.
${CLAUDE_PLUGIN_ROOT}/skills/slack/slack-notify.py \
--remind "Follow up on PR #1234"
Requires self_user_id in config or SLACK_SELF_USER_ID env var.
| Flag | Effect |
|---|---|
--broadcast | Also post thread reply to channel |
--reactions emoji1 emoji2 | Add emoji reactions after posting |
--unfurl | Enable link previews |
--message-file PATH | Read message body from a file |
--verbose | Show debug output |
MCP for reads, this script for sends. The MCP Slack tools are better for searching channels, looking up users, and reading threads. Use this script for all posting operations — it handles user group resolution and bot identity consistently.
<@USER_ID> (e.g., <@U040B2ES3N2>)<!subteam^GROUP_ID> (auto-resolved from config)@name does NOT notify anyone — always use ID syntax.To discover user IDs, use MCP slack_search_users tool.
*bold*, _italic_, ~strike~, `code`,
```code block```, >quote, bullet lists[text](url) links — use <url|text> instead| Error | Cause | Fix |
|---|---|---|
not_in_channel | Bot not added to channel | Add bot via channel settings → Integrations |
channel_not_found | Wrong channel ID | Verify ID in Slack |
No Slack token found | No token configured | Run first-time setup above |
missing_scope | Token lacks required permissions | Add scope in Slack app settings |
cant_delete_message | Trying to delete another user's msg | Bot can only delete its own messages |
This script is used by:
For multi-line messages, use the Write tool to create a temp file,
then pass via --message-file or $(cat /tmp/msg.txt). Do NOT use
heredoc (cat <<'EOF') — the bash security hook blocks it.