MailMesh exposes only 1 tool (list_email_accounts) with a READ_ONLY risk classification. The tool has a basic description but critically lacks an input schema definition, the source shows Input: {} with no formal JSON Schema. The description is minimal (54 chars) and does not explain when to use this tool, what it returns, or how results are structured. No parameter descriptions exist (there are no parameters). The tool definition appears inferred from oauth-smoke.mjs rather than explicitly registered in the MCP server code. No output schema is documented. Error handling is absent, no guidance on what happens if authentication fails or no accounts exist. This server prioritizes OAuth infrastructure over tool quality.

• Add formal JSON Schema to list_email_accounts input (even if empty, declare it as type: 'object', properties: {}, required: []). Make it explicit in src/mcp.ts.
• Expand tool description to 100 - 200 chars: 'Retrieve all email accounts linked to the authenticated user. Call this first to discover available mailboxes before reading or composing messages. Returns account list with IDs, addresses, and display names.'
• Document output schema: describe the response structure (e.g., array of {id, email, displayName, provider}), total count, and pagination if applicable.
• Add error handling: 'If no accounts are linked, guide the user to authorize an email provider. If auth fails, return 401 with scope requirements.'
• Move tool registration from oauth-smoke.mjs into src/mcp.ts so the tool definition is explicit and testable in the main server code.