Server has 8 tools with complete schemas and descriptions. Naming follows verb_noun convention (send_*, get_*, list_, read_). Descriptions are present (avg ~80 chars) but lack LLM-optimized guidance on WHEN to use each tool vs alternatives. Parameters are typed with enums where appropriate (mediaType, document_type). Error handling uses centralized fail() helper with type/message structure. Key gaps: no output schemas documented, no pagination guidance for list_chats/read_chat, no idempotency hints for write operations, descriptions don't explain prerequisites or recovery paths.

• Document output schemas for all tools. Example: send_message returns {success: boolean, message_id: string, timestamp: string, status: 'sent'|'pending'|'failed'}. This enables LLMs to chain tools and extract IDs for follow-up calls.
• Enhance descriptions with WHEN/WHY context. E.g. 'Send a plain text message to a WhatsApp recipient. Use this for simple text; use send_media_message for images/documents, or send_document_reminder for templated document requests.'
• Add pagination guidance to list_chats and read_chat. State: 'Returns up to [limit] chats/messages. Use limit parameter to control page size. If more results exist, call again with offset or cursor.'
• Add idempotency and confirmation hints to send_* tools. E.g. 'Sending the same message twice will result in duplicate messages. Consider storing message_id to avoid re-sending.'
• Enhance error responses with actionable recovery. In failValidation(), include the constraint violated and valid options. E.g. 'Invalid mediaType: got "photo", must be one of: image, document, audio, video'.