Graft has severe definition quality issues. Only 2 unique tools are actually defined (greet, lookup_weather, add); the other 4 entries are duplicates of 'greet'. Descriptions are minimal (10-30 chars, well below the 50-200 char baseline for LLM-optimized tools). Schemas are auto-generated from Go struct tags but lack explicit parameter descriptions in the schema itself. No output schemas documented. Error handling is present in the code but not surfaced in tool definitions. Tool names lack action verbs (greet is acceptable, but lookup_weather and add are generic). No evidence of pagination, batching, or composition patterns.

• Deduplicate tool registration. Remove the 4 duplicate 'greet' entries from the tool list. Verify that tool registration in mcp/server.go does not pollute the registry with test fixtures.
• Expand tool descriptions to 50-200 characters. Example: 'greet' → 'Generate a personalized greeting message for a person by name. Returns a string greeting. Use when you need to address someone warmly.'
• Document output schemas for each tool. Add a 'returns' field to ToolDefinition showing the structure of the result (e.g., greet returns {type: string}, lookup_weather returns {type: object, properties: {temp, condition, ...}}).
• Add format and constraint hints to parameter descriptions. Example: 'city' → 'The city name (string, 1-100 chars, e.g., New York, London). Use the canonical city name, not abbreviations.'
• Rename 'add' to 'add_numbers' and clarify the return type. Update description to: 'Add two numbers and return their sum. Accepts integers or floats. Returns a number.'