mailctx has 5 tools with complete input schemas and descriptions. Naming follows verb_noun convention (search_mail, get_thread, list_accounts, draft_reply, get_digest). Descriptions are present and moderately detailed (avg ~120 chars), meeting the 10-1024 char baseline. However, parameter descriptions are sparse or missing context. search_mail lacks guidance on date format handling and interaction between 'days', 'since', 'until'. draft_reply omits explanation of what 'never sends' means operationally. Output schemas are undocumented, LLMs cannot predict response structure. Error handling is minimal: search_mail catches exceptions but returns generic stderr output; draft_reply returns plain strings instead of structured error objects. No idempotency hints, no permission declarations, no rate-limit guidance. Token optimization is mentioned but not quantified. Overall: solid naming and basic schemas, but weak on parameter relationships, output documentation, and error recovery patterns.

• Document output schemas for all tools. E.g., search_mail returns Markdown string with fields: From, Subject, Date, Preview. get_digest returns categorized digest with counts per category. list_accounts returns array of account name strings.
• Clarify parameter relationships in search_mail: 'If both days and since/until are provided, since/until takes precedence. Omit days if using explicit date range.'
• Add min/max bounds to numeric parameters: limit (1 - 100, default 10), days (1 - 365, default 7). Specify date format as ISO 8601 (YYYY-MM-DD).
• Implement structured error responses. Return JSON objects with 'error', 'code', 'recovery_hint' fields instead of plain strings. E.g., {"error": "No matching accounts", "code": "ACCOUNT_NOT_FOUND", "recovery_hint": "Call list_accounts() to see available accounts."}
• Add idempotency and permission hints to draft_reply and search_mail descriptions. E.g., 'draft_reply is idempotent, retrying with the same parameters creates only one draft.' Declare required scopes: 'Requires read:email for search_mail, write:drafts for draft_reply.'