Single tool with acceptable naming (fetch_emails starts with verb) and documented schema structure. Description is present and reasonably detailed (178 chars), exceeding the 10-char minimum and falling within the production baseline range (avg 194 chars). Input schema explicitly defines 4 parameters with types and descriptions. However, output schema is not documented in the source code, critical omission for LLM planning. Parameter descriptions are adequate but lack enforcement details (e.g., no explicit constraint on limit max=50, folder enum values, or account_id format patterns). Error handling is not visible in the tool definition. No tool annotations (readOnlyHint, etc.) despite the tool being READ_ONLY. The 'unified' account feature is well-documented in description, reducing ambiguity.

• Document the output schema. Include example response structure: `{ emails: [ { id, subject, sender, snippet, date, folder, account_id }, ... ], total_count, limit_reached }`. This enables LLMs to plan extraction and avoid hallucinating fields.
• Add formal enum constraint for folder_name in parameter description: 'Folder name (enum): INBOX, Sent, Drafts, Spam, Archive, or custom folder name.'
• Clarify account_id format in description: 'Account identifier (string): use "unified" for all accounts, a specific email address (user@domain.com), account ID (alphanumeric), or "group:project-name" for group mailboxes.'
• Add readOnlyHint annotation to tool definition to signal to LLMs that this tool only reads and cannot modify email state.
• Add error handling documentation in tool description: 'On invalid account_id, returns error with available account list. On invalid folder, returns error with available folders for that account.'
• Specify pagination support in description if implemented: 'Returns up to limit results. To fetch additional results, pass offset or next_cursor in follow-up calls.' (Currently not visible in schema.)