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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so safety is covered. The description adds real value by disclosing what the record contains — pin roles, interfaces, I2C addresses, Arduino libraries, PCBBrew simulation status, purchase links and an image — which is the main behavioral unknown for this tool.

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?

A single sentence that front-loads the resource and key before the field list. The enumeration is long but each item earns its place because there is no output schema; slightly tighter phrasing would push this to a 5.

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?

For a one-parameter read tool with no output schema, the description fully covers both how to call it and what comes back, including domain-specific extras like simulation status and purchase info. Nothing an agent needs in order to invoke it correctly is absent.

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?

With one parameter at 100% schema coverage, the schema already documents the identifier, its length bounds and its provenance ('id from search_parts'). The description only restates 'by id' and adds no format or provenance detail beyond the schema, so baseline 3 applies.

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 states a specific resource ('One board or module from the catalogue') and the retrieval key ('by id'), then enumerates the payload fields. It is clearly distinct from search_parts or list_showcase, though the verb is implied rather than stated ('Fetch'/'Returns' is missing).

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 is implied: this is the by-id detail lookup that follows a catalogue search. The when-to-use context comes from the schema ('id from search_parts') rather than the description itself, and there is no explicit statement of when not to use it or what happens with an unknown id.

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