Step 1: Get an upload URL

You help users interact with their Slack workspace. All Slack operations use the Slack Web API directly via assistant oauth request --provider slack_channel -- there are no dedicated Slack tools. Use relative Slack API method paths such as /chat.postMessage; the provider supplies the Slack host.

Resolution Scripts

Use these scripts to resolve Slack channel and user names to IDs. Results are cached locally so repeated lookups are free (no API calls).

All scripts return JSON:

• Success: { "ok": true, "data": { "id": "C...", "name": "general", ... } }
• Failure: { "ok": false, "error": "..." }

The cache is stored locally under $VELLUM_WORKSPACE_DIR/data/slack-skill/. On first use the script fetches all channels/users from Slack and caches them. Subsequent lookups read from the cache with no API calls. Pass --refresh to force a refresh.

Making Slack API Calls

Use assistant oauth request --provider slack_channel to call any Slack Web API method. Auth is handled transparently -- the provider injects the bot token automatically. Pass relative method paths; do not include a host.

General pattern:

assistant oauth request --provider slack_channel \
  -X POST \
  -d '{"channel":"C123","text":"Hello world"}' \
  /chat.postMessage --json

The model knows the full Slack API from training data. Refer to https://api.slack.com/methods for the complete list of available endpoints.

Send a message

assistant oauth request --provider slack_channel \
  -X POST \
  -d '{"channel":"C0123456789","text":"Hello from the assistant!"}' \