Presend has clear, well-structured tool definitions with complete schemas and good descriptions. All 5 tools are explicitly registered with proper JSON Schema. Naming follows verb_noun convention (check_message, fix_message, save_profile, list_profiles, delete_profile). Descriptions are substantive (100-200 chars, within baseline 194 avg). However, output schemas are not documented, callers cannot predict response structure. Error handling is basic (generic error messages, no recovery guidance). Parameter descriptions are adequate but lack format constraints and validation rules. No tool annotations (readOnlyHint/destructiveHint) despite clear risk levels. Missing idempotency guidance for profile operations.

• Document output schemas for all tools. E.g., check_message returns {score: number, flags: {red: string[], yellow: string[], green: string[]}, summary: string}. This enables LLMs to chain calls and extract fields reliably.
• Add tool annotations to schema: check_message and list_profiles get readOnlyHint: true; save_profile gets destructiveHint: false (it's upsert, not delete); delete_profile gets destructiveHint: true. This signals intent to agents.
• Enhance error messages with recovery hints. E.g., 'Profile not found: boss-joao. Call list_profiles() to see available profiles, or create one with save_profile().'
• Add format/constraint descriptions to parameters. E.g., profile_id: 'Slug identifier (lowercase, hyphens only, 3-50 chars). E.g. boss-joao, client-acme.'
• Document idempotency: 'save_profile is idempotent, calling twice with the same id and description produces the same result. Safe to retry on transient failures.'