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

Annotations already declare readOnlyHint=true and openWorldHint=false, and the description adds real behavior beyond that: parts are ranked, each requirement is classified as meets/close-within-15%/misses/unknown, and the response surfaces the single most blocking requirement plus a relaxation hint. It does not cover paging or how the fit score is composed beyond the 'priorities count double' schema note.

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 sentences, front-loaded with the core action, then output semantics, then the prerequisite call. Dense but nearly every clause earns its place; the first sentence is long but carries the essential scope.

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?

With no output schema, the description does the necessary work of describing return values including per-requirement verdicts and the blocking-requirement summary. Given a mutation-free read tool with annotations covering safety, it is close to complete, with the uncovered sourcing parameters (lens, ndaa_only) the main residual gap.

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?

Schema description coverage is only 14% across 7 parameters, so the description has to carry meaning, and it only explains subcategory and the shape of requirements (key plus numbers). The lens, ndaa_only, qty and limit parameters receive no explanation in either the description or the schema, leaving a substantial gap.

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 opens with a specific verb and resource ('Route a design requirement to parts') and immediately defines both inputs (subcategory plus the numbers needed) and the output (every part ranked). It is clearly distinct from listing or comparison siblings because it is scoped to requirement-driven ranking.

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?

It gives a concrete prerequisite workflow: 'Call requirement_keys first to see which keys a subcategory accepts,' which prevents a malformed call. It also supplies example subcategory values (joint-actuators, strain-wave-reducers, frameless-bldc), though it never states when to prefer compare_parts or search_parts instead.

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