Gmail plugin has basic tool definitions but significant quality gaps. All 5 tools have names and descriptions, but descriptions are generic (avg 80 chars, below 194-char baseline). Input schemas present but minimal, most parameters lack type info beyond 'string'. No output schemas documented. Error handling is absent; tools return raw API errors without recovery guidance. No parameter validation, enums, or constraints. Missing idempotency hints for destructive operations (send-email, trash-email). Prompts defined but generic. No tool annotations (readOnlyHint, destructiveHint). Composition is reasonable (5 focused tools), but parameter naming lacks specificity (e.g., 'recipient_id' should clarify it's an email address, not a user ID).

• Add output schemas for all tools. E.g., send-email should return {status: string, message_id: string, timestamp: ISO8601}. get-unread-emails should return {emails: [{id, from, subject, preview, timestamp}], total_count: int, next_cursor?: string}.
• Expand tool descriptions to 100 - 200 chars. Include WHEN to use, state-change warnings for destructive ops, and any prerequisites. E.g., 'Sends an email to the specified recipient. Requires confirmation from user. Returns message_id for tracking.'
• Add parameter constraints and enums. E.g., subject max 255 chars, message max 10000 chars. Document format expectations (email must match RFC 5322).
• Implement error recovery guidance. E.g., 'Failed to send email: recipient address invalid. Try search_contacts() to find the correct email.' Categorize errors as retryable vs user-fixable.
• Add tool annotations: mark send-email and trash-email with destructiveHint=true; mark read-email and get-unread-emails with readOnlyHint=true. Enables LLM safety reasoning.

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

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