The server defines a single tool 'send_message' with a well-structured schema and comprehensive description. The tool name follows verb-noun convention (send_message) and clearly conveys its action. The description is detailed (500+ chars) and includes specific formatting guidance for Slack mrkdwn, mention handling, and URL extraction instructions. All four parameters are properly typed and include descriptions. However, the parameter naming could be more explicit (e.g., 'channel' could be 'channel_id_or_name' to clarify it accepts both), and the output schema is not documented, callers must infer the response structure from the implementation.

• Document the return value structure in a comment above the tool definition, e.g., 'Returns {ts: string, channel: string, message: string, thread_ts?: string}' so LLMs know what fields to expect.
• Rename 'channel' parameter to 'channel_id_or_name' and update description to explicitly state: 'Either a Slack channel ID (e.g., C0AGCGG628K) or channel name without # (e.g., general). IDs are preferred and more reliable.'
• Add error guidance in parameter descriptions: 'message must not be empty and should use only Slack mrkdwn syntax (see formatting guidelines in tool description).'
• Consider adding an optional 'dry_run' boolean parameter (defaulting to false) that validates the message format and channel existence without posting, enabling preview-before-send workflows.