Search Parts Registry

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already state readOnly, openWorld, idempotent, non-destructive. The description adds valuable behavioral context: the registry is 'gate-verified', has '18k+ verified parts, no auth', supports 'case-insensitive substrings' over specific fields, and can be pointed to any 'compatible registry' via PARTREEL_API_BASE. These details go beyond the annotations and inform the agent of data quality and flexibility.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three concise sentences, each earning its place: purpose, differentiation from sibling, and registry/matching details. No filler or repetition of schema/annotations. Front-loaded with the most critical usage instruction.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's moderate complexity, an output schema exists, and annotations cover safety, the description covers all needed context: purpose, position in workflow, registry details, matching behavior, and configuration. No significant gaps for an agent to select and invoke the tool correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Input schema covers all 3 parameters with descriptions, so baseline is 3. The description enhances query semantics by explaining 'Matches are case-insensitive substrings over the part name, keywords, family, and manufacturer', which clarifies how the query parameter behaves beyond the schema's free-text example. It doesn't add details for limit or category, but they are self-explanatory.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose: 'Search an open, gate-verified parts registry for existing KiCAD parts BEFORE generating a custom footprint/symbol from scratch.' It identifies the verb, resource, and specific workflow context. It also explicitly distinguishes itself from search_jlcpcb_parts, making its role unambiguous.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage guidance is explicit: use this tool before creating custom assets, and use search_jlcpcb_parts for JLCPCB sourcing data. It also explains the default registry, environment variable override, and matching behavior. This provides clear when-to-use and alternatives.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.