Strong foundation with all 7 tools properly named, described, and schematized. Tool names follow verb_noun convention (list_, get_, send_, search_). Descriptions are clear and action-oriented (avg ~100 chars, within 10-1024 baseline). All parameters have type definitions and descriptions. Pagination support present (limit, cursor). However, output schemas are not explicitly documented in the source, responses are JSON-stringified without formal schema declarations. Error handling returns isError flag but lacks recovery guidance (e.g., 'Try search_users() first'). No tool annotations (readOnlyHint/destructiveHint) despite clear risk classifications. Parameter constraints could be more explicit (e.g., limit ranges stated in descriptions but not as JSON Schema min/max).

• Add formal output schema declarations for all tools. Document return types as JSON Schema (e.g., 'Returns: {type: object, properties: {channels: {type: array, items: {type: object, properties: {id, name, is_archived}}}}}').
• Enhance error messages with recovery guidance. E.g., catch 'user_not_found' and return 'User not found. Try search_users() with a partial name.' instead of raw error text.
• Add tool annotations: mark slack_send_message with destructiveHint=true; mark all read-only tools with readOnlyHint=true. This enables agents to reason about side effects.
• Formalize parameter constraints in JSON Schema using min, max, pattern, enum. E.g., limit: {type: number, minimum: 1, maximum: 200}. Keep descriptions as human-readable summaries.
• For slack_send_message, add optional dry_run parameter (boolean, default false) to preview the message before posting. Return the formatted message without sending if dry_run=true.