Six tools with complete input schemas and descriptions, but significant gaps in parameter documentation and output schema clarity. Tool names follow verb_noun convention (reply, send, react, edit_message, send_link, check_capability). Descriptions range 50 - 180 chars, meeting baseline minimums. However, 3 of 6 tools have underdocumented parameters: reply's text_decorations array lacks item descriptions; send's effect and files parameters lack format/constraint details; send_link's text parameter is optional but unmarked. No output schemas documented for any tool. Error handling absent, no guidance on retryability, user-fixable errors, or recovery paths. The edit_message tool description mentions iOS 16+ requirement but no validation. Overall: functional definitions suitable for basic use, but below production quality for agent reliability.

• Document output schema for each tool. At minimum: reply returns {message_id, chat_id, timestamp}; send returns {message_id, to, timestamp}; check_capability returns {phone, supports_imessage, supports_rcs}. This enables tool chaining (reply → edit_message).
• Convert effect parameter in reply and send to enum: ['confetti', 'fireworks', 'lasers', 'sparkles', 'celebration', 'hearts', 'love', 'balloons', 'happy_birthday', 'echo', 'spotlight', 'slam', 'loud', 'gentle', 'invisible']. Remove examples from description.
• Add descriptions to text_decorations array items: range should be [start_index, end_index) as integers; style should be enum ['bold', 'italic', 'strikethrough', 'underline']; animation should be enum ['big', 'small', 'shake', 'nod', 'explode', 'ripple', 'bloom', 'jitter'].
• Add error handling guidance to send and check_capability: 'Returns error if phone number is invalid (not E.164 format). Try check_capability first to verify number supports iMessage/RCS.' Add retryability hints for network errors.
• Add file validation constraints to reply and send descriptions: 'Files must be absolute paths. Supported types: JPEG, PNG, GIF, MP4, MOV, M4A, PDF. Max 100MB per file. Returns error if file not found or exceeds size limit.'