Gmail MCP server has basic tool definitions but significant quality gaps. All 5 tools have names and descriptions, but descriptions are minimal (10-50 chars, well below the 194-char baseline). Input schemas are present for 4/5 tools but lack depth, parameters have types and descriptions, but no enums, ranges, or format constraints. Output schemas are undocumented. Error handling is minimal (HttpError caught but responses lack recovery guidance). No tool annotations (readOnlyHint, destructiveHint). The send_email and trash_email tools are destructive but lack confirmation patterns. Parameter naming is inconsistent: 'recipient_id' should be 'recipient_email' for clarity. No pagination support for get_unread_emails despite potentially large result sets.

• Expand tool descriptions to 100-200 chars. Include WHAT the tool does, WHEN to use it (vs similar tools), and any prerequisites. Example: 'Send an email to a recipient. Use this after drafting content with the draft-email prompt. Requires recipient email address and subject line. This action is irreversible, confirm with the user first.'
• Add confirmation/dry-run pattern to send_email and trash_email. Return a confirmation_required response with a summary, requiring explicit user approval before executing the destructive action.
• Document output schemas for all tools. Specify return type (dict, list, string), field names, types, and meanings. Example: send_email returns {status: 'success'|'error', message_id: string, error_message?: string}.
• Add pagination to get_unread_emails: accept limit (1-100, default 20) and offset parameters; return {messages: [...], total_count: int, has_more: bool}. Cap results at 50 to prevent context window exhaustion.
• Rename 'recipient_id' parameter to 'recipient_email' and update description to clarify it accepts email addresses, not user IDs. Add validation to reject non-email formats with actionable error: 'Invalid recipient: must be a valid email address (e.g., [email protected])'.

Inferred effective spec: <=2025-11-25.

• Relies on Logging (deprecated) - log to stderr or use OpenTelemetry