Server has 12 tools with mostly complete schemas and descriptions. Naming follows verb_noun conventions consistently (search_, list_, get_, send_, download_). Descriptions are present and reasonably detailed (average ~120 chars). Input schemas are well-formed JSON Schema with types and descriptions for all parameters. However, output schemas are not documented, LLMs cannot determine what fields to expect from responses, forcing them to reason about downstream chaining. Error handling guidance is missing entirely, tools provide no recovery hints when operations fail. Parameter descriptions lack some actionable constraints (e.g., phone number format, JID syntax rules are mentioned but not formally constrained as regex patterns or enums). Security concerns are significant: the server interacts with WhatsApp and sends messages (WRITE operations), but lacks permission gates, rate limiting, and dry-run/confirmation patterns for destructive operations. Resource composition is reasonable, tools are mostly single-responsibility, but some tools could be combined (e.g., send_message and send_file share recipient format logic).

• Document output schemas for all 12 tools. For send_message, document whether it returns {success: bool, message_id: string, timestamp: ISO8601}. For list_messages, document {messages: [{id, sender, content, timestamp, ...}], total_count: int, page: int, has_next: bool}. This enables confident chaining and reduces hallucination.
• Add error recovery guidance to send_message, send_file, send_audio_message. E.g., on invalid recipient format: 'Invalid recipient format. Expected a phone number (e.g., 12025551234) or JID (e.g., 12025551234@s.whatsapp.net for direct chat, 123456789@g.us for group). If you only have a name, call search_contacts() first.'
• Implement confirmation pattern for WRITE tools. Add a dry_run parameter (default: false) to send_message, send_file, send_audio_message. When dry_run=true, validate and return what would be sent without actually sending. This prevents accidental messages.
• Formalize parameter constraints using JSON Schema pattern or enum. For recipient parameter, use pattern: '^[0-9]{1,15}@(s\.whatsapp\.net|g\.us)$|^[0-9]{1,15}$' and description: 'Phone number (digits only, no + or spaces, e.g. 12025551234) or JID (e.g. 12025551234@s.whatsapp.net for direct, 123456789@g.us for group).'
• Add total_count and next_cursor to paginated responses. E.g., list_messages should return {messages: [...], total_count: 342, page: 0, page_size: 20, has_next: true} so LLMs can compute pagination without guessing.
• Declare permission scopes for each tool in descriptions. E.g., 'Requires: read:messages, read:contacts. No send/delete permissions.' This enables least-privilege agent setup and audit clarity.