MS Graph MCP has well-structured tool definitions with consistent naming (verb_noun pattern) and complete input schemas. All 6 tools follow the verb_noun convention (mail_list_messages, calendar_create_event, onedrive_*). Descriptions are present and adequate (50-100 chars), though some lack actionable context for LLM selection. Input schemas are properly typed with JSON Schema. However, output schemas are not documented in the source, parameter descriptions lack constraint details (e.g., OData filter syntax), and error handling guidance is absent. No tool annotations (readOnlyHint/destructiveHint) despite clear risk classifications. Missing pagination guidance for list operations.

• Document output schemas for all tools. Example for mail_list_messages: 'Returns array of {id, subject, from, receivedDateTime, bodyPreview, hasAttachments}'. Include all fields LLMs need for downstream calls.
• Add tool annotations to tool definitions. Mark calendar_create_event and onedrive_create_folder with destructiveHint=true; mark read-only tools with readOnlyHint=true. This enables LLM safety reasoning.
• Enhance parameter descriptions with concrete constraints. Replace 'OData $filter expression' with 'OData $filter expression (e.g., "from eq '[email protected]'")'. Add min/max to numeric params: 'top: 1 - 999, default 20'.
• Add pagination guidance to list tools. Document: 'Returns up to 20 items by default. Use top parameter to request more (max 999). For large result sets, implement cursor-based pagination via skip/top combination.'
• Add error handling guidance to tool descriptions. Example: 'If folder not found, returns error with available folder names. If quota exceeded, returns 429 with retry-after guidance. If auth fails, user must re-run init command.'

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

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