version: "1.0.0" name: send-slack-message description: >- Post a message to a Slack channel using a Slack bot token via the Slack Web API, and return a clickable permalink to the posted message. Use this whenever the user wants to send, post, or announce a message to a Slack channel through a bot, drop a notification into Slack, or push text to a Slack channel programmatically — even if they don't say "API". Takes a channel and message text; posts as the bot and returns the message link.

Send Slack Message (Bot)

Posts a message to a Slack channel as a bot and returns a clickable link to the posted message. Uses the Slack Web API (chat.postMessage + chat.getPermalink) over HTTPS — no browser or UI automation, so it is fast and reliable.

Credentials

Requires a Slack bot token stored under service slack:

• slack.bot_token — a bot token (xoxb-...) with the `chat:write` scope

(add `chat:write.public` too if the bot is not invited to the target channel). The installer is prompted to fill credentials.template.json.

Inputs

Read from the JSON file passed via --inputs-json. See inputs/inputs.example.json and inputs/inputs.template.json.

• channel (required) — channel name (e.g. #general) or channel ID (e.g. C0BB39TU3AS).
• message (required) — the text to post.

Run

./run.sh inputs/inputs.example.json
# or
"$AI_MIME_PYTHON_PATH" scripts/run.py --inputs-json inputs/inputs.example.json

Runtime contract:

• run.sh uses the first available interpreter in this order: skill

.venv/bin/python, workflow .venv/bin/python, then required $AI_MIME_PYTHON_PATH.

• No requirements.txt — the script uses only the Python standard library

(urllib), so no .venv is required. Runtime does not create or repair a .venv.

Outputs

On success, prints a one-line confirmation with the message link and emits a workflow_done event whose outputs contain:

• channel — the channel input as provided.
• channel_id — the resolved Slack channel ID.
• ts — the posted message timestamp.
• permalink — clickable Slack link to the message (may be null if the

permalink lookup fails, though the message is still posted).

Progress log format

Structured JSON events are emitted on stderr:

• {"event":"step_start","id":"<step_id>","title":"…"}
• {"event":"step_done","id":"<step_id>","outputs":{…},"summary":"…"}
• {"event":"step_failed","id":"<step_id>","error":"…","recoverable":false}
• {"event":"workflow_done","outputs":{…}}

Step ids: post_message, get_permalink. Exits non-zero on step_failed.

Fallback

If the API call fails, see references/fallback_plan.md. Common errors are mapped to plain-language guidance in the script (missing_scope, not_in_channel, channel_not_found, invalid_auth). The fallback covers fixing scopes/membership and posting manually via the Slack app.

ask_llm decision points

None. The task is fully deterministic — no ask_llm calls.

References

• references/fallback_plan.md — recovery steps and Slack API error guidance.