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

Annotations already mark it readOnly, idempotent, and non-destructive; the description adds that it only searches public catalog rows and 'only returns catalog matches', making clear this is a data lookup rather than a computation tool. This is meaningful behavioral context beyond the annotations, though it doesn't detail pagination or exact-match behavior.

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 with a front-loaded one-line purpose, an explicit use-when list, and a clear exclusion. No filler; every sentence earns its place.

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 full parameter documentation, output schema, and safe annotations, the description covers scope, result content, and the key misuse case. It doesn't explicitly distinguish itself from search_fibers/search_lenses within the text, but the domain-specific resource and fields make that distinction inferable.

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?

The schema already documents all four parameters, so the baseline is 3; the description raises this by explaining the intended query style (part number or short component phrase, vendor-neutral terms unless vendor/family named) and lists catalog attributes that map to search terms. It adds meaning without repeating schema details.

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?

Opens with a specific verb and resource — 'Search public fiber-collimator catalog rows' — and enumerates the real-world attributes it returns (part numbers, EFL, coating range, connector type, clear aperture). This clearly distinguishes it from the sibling lens/fiber search tools and generic optical calculators.

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?

The description gives explicit trigger conditions ('Use when the user asks for real collimator/coupler part numbers, links, EFL, coating range, connector type, clear aperture, or vendor data') and an explicit exclusion ('Do not use as a generic Gaussian-beam solver'). It does not name a specific sibling alternative for the excluded case, so it falls just short of fully explicit alternative routing.

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