The server demonstrates solid fundamentals with clear tool naming (verb_noun pattern), well-structured input schemas using Zod, and explicit JSON Schema definitions. All 5 tools are properly registered with descriptions and input validation. However, output schemas are undocumented, LLMs cannot see what fields to expect from responses. Parameter descriptions are present but inconsistent in depth. Security is well-handled with account-based isolation and no exposed secrets. Error handling exists but lacks actionable guidance for LLM recovery.

• Add explicit output schema documentation for all 5 tools. Example for read_emails: 'Returns {messages: Array<{id: string, from: string, subject: string, date: ISO8601, preview: string}>, total: number, hasMore: boolean}'. This enables chaining and lets LLMs understand what data is available.
• Enhance delete_email description to: 'Permanently delete a message. WARNING: This action is irreversible. Use with caution as deleted emails cannot be recovered.'
• Implement structured error responses with classification field: {isError: true, errorType: 'user_fixable'|'retryable'|'fatal', message: '...', guidance: '...'} per pattern:recovery-guide. Example: {errorType: 'user_fixable', message: 'Account not configured', guidance: 'Set EMAIL_ACCOUNTS_JSON or use X-Email-Account header'}
• Document pagination behavior in read_emails and search_emails descriptions. Add fields to responses: total_count, cursor_next (if applicable). Explain how limit interacts with result sizes.
• For send_email attachments, add description clarifying: 'Each attachment must have filename and either path (to local file) or content (inline string). Maximum 20 attachments per email.'
• Add idempotentHint annotations to read_emails and search_emails (read-only operations), and destructiveHint to delete_email per current spec patterns.
• Document which parameters accept multiple account types (account name vs email vs ID) in the account parameter description: 'Account identifier: can be a named account from EMAIL_ACCOUNTS_JSON, email address, or account ID.'

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

• Relies on Stateful initialize / Mcp-Session-Id (removed; protocol is stateless) - make each request self-contained