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

Adds meaningful behavioral context beyond the readOnlyHint and idempotentHint annotations: it explains rotation/scale invariance, the numeric distance scale (0 to ~1.414), and a rule of thumb for near-duplicates. No contradictions with annotations.

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?

Well-structured with the purpose stated first, followed by the similarity metric, threshold guidance, and prerequisite. Every sentence provides essential information without fluff, making it easy for an agent to parse.

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 sufficiently explains what to expect (similar parts) and how to interpret distances, plus provides a threshold. It covers the input requirement and the core semantics, making it complete for a read-only tool. The annotations already handle safety.

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 coverage is 100%, so the baseline is 3. The description enriches parameter semantics by explaining the meaning of maxDistance (distance cut-off, with ~0.05 for near-duplicates) and ties it to the distance scale. It also gives guidance for obtaining partRevisionId via query, which is beyond the schema's simple 'UUID' description.

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?

Clearly states it finds part revisions most similar in shape, with a precise definition of similarity as a geometric distance. It also explicitly distinguishes itself from inspectPartRevision by noting that real dimensions are covered there, so an agent can tell them apart.

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?

Provides concrete guidance on when to use it (shape/proportion matching) and when not to (if real dimensions are needed, use inspectPartRevision). Also explains the prerequisite (UUID) and how to obtain it via query(entity='partRevision').

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