Server has 2 tools with complete schemas and descriptions. greet is trivial (simple greeting). send_email is substantive with comprehensive parameter coverage (recipients, content, attachments, scheduling, tags) and proper Zod validation. Both tools have descriptions and input schemas. However, descriptions are brief (greet: 24 chars, send_email: 77 chars) and lack actionable context for LLM selection. send_email lacks output schema documentation, callers cannot predict response structure. Error handling is present (missing API key, missing content) but generic. No tool annotations (readOnlyHint/destructiveHint). Parameter descriptions are minimal; many lack format/constraint guidance. Naming is clear (verb_noun pattern). No secrets exposed as parameters (API key extracted from headers). Composition is reasonable but send_email is complex with many optional parameters that could benefit from clearer dependency documentation.

• Expand tool descriptions to 150-250 chars. For send_email: 'Send emails via Resend API with support for HTML/text content, attachments, scheduling, and custom tags. Requires X-Resend-API-Key header. Returns email ID on success or error details on failure.'
• Document output schema for send_email. Specify: 'Returns {id: string, message?: string} on success, or {isError: true, content: [{type: "text", text: string}]} on failure.'
• Add parameter descriptions for optional fields. E.g., scheduled_at: 'ISO 8601 datetime or natural language (e.g., "tomorrow at 9am") to schedule email delivery. Omit for immediate send.'
• Add tool annotations: send_email should include destructiveHint=true in server.tool() call; greet should include readOnlyHint=true.
• Improve error handling for Resend API failures. Parse response.json() and return actionable error: 'Resend API error: {error.message}. Check sender_email is verified and recipients are valid.' instead of raw API response.