Slack

Use the message tool with channel: "slack". The tool schema lists the actions enabled for the current Slack account; do not assume an action that is not present.

Workflow

• Prefer stable Slack IDs from context. Sends outside the current conversation use channel:<id> or user:<id> targets.
• Keep replies in the current thread unless the user asks for a top-level post. For another thread, pass its Slack timestamp as threadId; use the same timestamp as messageId for message-specific actions.
• Before editing, deleting, pinning, or reacting to an ambiguous message, read the conversation and resolve its exact ID.
• When multiple Slack accounts are configured, pass accountId rather than guessing.
• Confirm destructive deletes when the target or intent is unclear.

Slack formatting, mentions, and available actions are described automatically by the current message tool hints. Follow those hints instead of maintaining a second action catalog here.