The server defines 15 WhatsApp tools with reasonable action verb naming (search_*, get_*, list_*, send_*, mark_*, download_*) and generally adequate descriptions (mostly 50-150 chars). However, critical gaps reduce the score: (1) Output schemas are NOT documented, no response structure visible for any tool, making it impossible for LLMs to plan downstream chains; (2) Parameter descriptions are present but often terse, lacking format/range constraints, especially for complex params like 'identifier' in get_contact (accepts phone, LID, or JID but doesn't explain the format clearly); (3) No input validation guidance in descriptions (e.g., list_messages 'limit' accepts 1-500 but this is not stated in description, only in source); (4) Error handling not visible, no evidence of actionable error messages or recovery guidance; (5) Tools like send_message, send_file, send_audio_message, send_reaction, and mark_messages_read are destructive but descriptions do NOT flag them as write operations or acknowledge side effects; (6) No documented pagination metadata (e.g., does list_messages return total_count for pagination?); (7) Backward-compatibility aliases (phone_number, phone) in get_contact add confusion without clear guidance on which to use. Positive: tool names follow verb_noun convention; most descriptions are non-empty; parameter counts are reasonable (2-10 per tool). The server is competent but lacks the polish and documentation maturity of production-grade tools.

• Document the output schema for every tool. E.g., list_messages should state: 'Returns an array of Message objects, each with: message_id (string), sender (string), content (string), timestamp (ISO-8601), is_from_me (boolean), media_type (string|null), filename (string|null). Also returns pagination metadata: page (int), total_count (int), has_more (bool).'
• Add explicit write/side-effect flags to destructive tool descriptions. Prefix send_message, send_file, etc. with: 'WRITES TO WHATSAPP. This action sends a message and cannot be undone.'
• Clarify identifier format in get_contact description. Replace current description with: 'Look up a WhatsApp contact by phone number, LID, or JID. Automatically detects the identifier type. Accepted formats: phone number (11-15 digits, e.g. "12025551234"), LID (numeric ID, e.g. "35047067385985"), phone JID (e.g. "12025551234@s.whatsapp.net"), or LID JID (e.g. "184125298348272@lid").'
• Document numeric bounds in parameter descriptions. For list_messages, add to 'limit' description: 'Maximum number of messages to return (1-500, default 50).' Similarly for list_chats (1-200), get_contact_chats (no explicit max stated but likely should have one).
• Add pagination guidance. Append to list_messages and list_chats descriptions: 'Use page (0-indexed) and limit to paginate through results. The response includes total_count and has_more fields to help iterate.'
• Consolidate get_contact parameter names. Remove phone_number and phone aliases; use only 'identifier'. Update description to make clear what formats are accepted.