This Google Chat MCP server provides 9 well-named tools with clear action verbs (list_, get_, send_, delete_, upload_). Descriptions are present and mostly adequate (averaging ~120 chars, within production baseline of 194). All tools have input schemas with type definitions and parameter descriptions. However, output schemas are not documented, LLMs cannot predict what fields will be returned. Parameter descriptions lack actionable constraints (e.g., page_size has a max of 1000 but this is mentioned only in the description text, not enforced via schema limits). Error handling is not visible in the provided code, and destructive operations (delete_message, upload_attachment) lack any confirmation/dry-run pattern. Resource names use opaque IDs (spaces/AAAA1234, messages/BBBB5678) without accepting human-friendly alternatives, users say 'send to Engineering' not 'send to spaces/AAAA1234'. Tools are well-composed (each has a single responsibility), but chaining is unclear because responses aren't shown. Security is good: credentials handled via OAuth2 token injection (not exposed as parameters). Overall: solid foundations, but output documentation and error guidance are missing.

• Document output schemas for all tools. Specify the fields returned by list_spaces (e.g., name, displayName, type, createTime), so LLMs know what data is available and can plan multi-step calls. Use the format: 'Returns: {name: string, displayName: string, type: string, createTime: string, ...}'.
• Add a confirmation step for destructive operations. Implement a pattern like: delete_message first returns {message_name, preview_text, confirm_key}, then requires a DELETE_CONFIRM call with that confirm_key. Or add a 'confirm=true' required parameter that defaults to false for safety.
• Support human-friendly identifiers for space parameters. Accept either spaces/AAAA1234 OR 'Engineering' display name in space_name. Internally resolve display names to IDs via list_spaces filtering. This matches the chat data model.
• Formalize parameter constraints in JSON Schema. Add 'minimum': 1, 'maximum': 1000 to page_size numeric schemas. Add 'pattern': '^spaces/[A-Za-z0-9]+$' for space_name to guide LLM input validation.
• Add actionable error messages. When get_space fails with 404, return: 'Space not found: spaces/AAAA1234. Call list_spaces() to discover available spaces.' When permission is denied, return: 'Permission denied. The service account may not have access to this space. Verify credentials.'
• Enhance tool descriptions with discovery guidance. E.g., 'list_messages searches all messages in a space. Call this first to find message IDs. If you know the exact message ID, use get_message instead to fetch details.'

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

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