Server has 12 well-named tools with complete input schemas and descriptions. All tools follow verb_noun naming (list_emails, send_email, etc.). Descriptions are present and adequate (50-150 chars typical), exceeding the 20-char minimum. Input parameters have types and descriptions. However, output schemas are not documented, responses are JSON-serialized but the structure of returned objects is not specified in tool definitions. Error handling is minimal; no recovery guidance or categorization. No tool annotations (readOnlyHint, destructiveHint) despite clear risk levels. Missing pagination guidance for list tools. No idempotency guarantees stated.

• Document output schemas for all tools. Specify the structure of email, event, and contact objects returned (e.g., email has id, subject, from, to, body, timestamp; event has id, title, start_time, end_time, participants). Use JSON Schema or a clear text description.
• Add tool annotations to the MCP tool definitions. Mark send_email, create_event, delete_event with destructiveHint=true; mark all read-only tools with readOnlyHint=true. This enables agents to reason about safety.
• Add error handling guidance to tool descriptions. E.g., send_email: 'Returns error if recipient email is invalid or account quota exceeded. If quota error, suggest checking account limits before retrying.'
• Document pagination for list tools. Specify: 'Returns up to {limit} results. If more exist, include a next_cursor or total_count in response. Use cursor parameter to fetch next page.' Clarify behavior when limit is exceeded.
• Add a confirm_delete_event tool or a dry_run parameter to delete_event. Alternatively, document that delete_event is irreversible and agents should ask for confirmation before calling.