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

With annotations already covering readOnly/destructive/idempotent/openWorld, the description adds real context: pin groupings are derived from resolved pin functions, no IEEE/IEC drawing standard is applied, and the output is validated only via kicad-cli 'sym upgrade' as a file-format check, not DRC/ERC. One residual tension: the leading verb 'Write a ... library' implies file emission while readOnlyHint=true, and the description never clarifies whether a file is written server-side or content is returned.

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 dense sentences with zero padding: artifact and groupings first, generation source second, validation caveat last. Every sentence carries distinct information an agent needs.

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?

An output schema exists and the safety profile is annotated, so the description only needs to carry generation semantics and caveats, which it does. The one missing piece is the write-vs-return behavior of the emitted file, which matters given the 'Write' phrasing against a readOnly hint.

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% (documentPath URL/local-path distinction, optional partName and packageSelection are fully documented in the schema), so the schema does the heavy lifting. The description adds no parameter-level meaning, which is acceptable at this coverage level but earns only the baseline.

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?

States a specific verb and artifact: emit a KiCad .kicad_sym symbol library from a datasheet pinout, with named logical pin groupings. The scope is unambiguous against generic extraction siblings, but it never names the closely related datasheetvend_extract_kicad_footprint or datasheetvend_extract_kicad_bundle, so a caller must infer which KiCad artifact it wants.

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 only implied: 'generated from the pin functions the pinout module resolved' hints that extract_pinout should run first, and the 'no IEEE/IEC standard applied' note hints this is a functional rather than standards-grade symbol. There is no explicit when-to-use / when-not-to-use statement or comparison to the footprint and bundle siblings.

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