Server has 9 tools with basic descriptions and parameter schemas, but significant quality gaps. All tools have descriptions (good), but most are generic and under 100 chars. Parameter schemas are present but lack depth: many parameters missing type constraints (e.g., 'tuple' for date_range in list_messages is non-standard JSON Schema). No output schemas documented. Error handling is absent, no recovery guidance, no actionable error messages. Tool naming is verb-first (good), but descriptions don't explain WHEN to use each tool or dependencies between them. The send_message tool lacks confirmation/dry-run pattern despite being destructive. No tool annotations (readOnlyHint/destructiveHint) despite clear risk levels.

• Convert parameter schemas to valid JSON Schema: replace 'tuple' with 'object' or 'array'; add 'format' for dates (ISO 8601); add 'enum' for sort_by and other constrained fields.
• Document output schemas for all tools. E.g., list_chats returns [{chat_jid, name, last_message_time, last_message?}]. Include field types and which fields are required for chaining.
• Add tool annotations: readOnlyHint=true for 8 read tools, destructiveHint=true for send_message, idempotentHint=true for get_* tools.
• Expand send_message description to 150+ chars: explain phone format (country code, no +), what happens on invalid input, and add a dry_run parameter or confirmation step.
• Add dependency hints to descriptions: 'Call list_chats() first to get chat_jid if you only have a contact name.' This guides multi-step planning and reduces wasted calls.