MoldSim MCP demonstrates solid tool design with clear naming, comprehensive descriptions, and well-structured schemas. All 6 tools follow verb_noun conventions (query_, get_, validate_, generate_, compare_, generate_). Descriptions are detailed (150-250 chars) and explain WHEN to use each tool. Input schemas use Zod with type definitions and parameter descriptions. However, output schemas are not documented, responses are text-only without structured field definitions. Error handling is minimal; no recovery guidance or validation error messages visible. Tool composition is sound (each does one thing), but no pagination support for potentially large results (e.g., query_simulation_knowledge could return many matches).

• Document output schemas for all tools. Define structured response objects with typed fields (e.g., material_properties returns {cross_wlf: {...}, pvt: {...}, thermal: {...}} instead of plain text). This enables LLMs to extract and chain data.
• Add input validation and error messages. Validate numeric ranges (melt_temp_C: 150-400°C for most plastics), enum constraints (gate_type), and material names. Return actionable errors: 'Invalid melt temperature 50°C, must be 150-400°C for ABS. Try 220-240°C.'
• Implement pagination for query_simulation_knowledge. Add limit (default 20, max 100) and offset parameters. Return total_count and next_offset to enable multi-turn discovery.
• Convert gate_type parameter to enum constraint: z.enum(['edge', 'sub', 'pin', 'hot', 'fan', 'tunnel']). Remove free-form string acceptance.
• Add numeric range constraints to validate_process_parameters. Document expected ranges in descriptions: 'melt_temp_C: 150-400°C depending on material' and validate in implementation.