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

No annotations are provided, so the description carries the full behavioral burden. It adds useful provenance — the graph size (312,913 cross-references) and a measurement date — but says nothing about ordering, empty results, directionality of the cross-reference, or performance.

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 front-loaded sentence whose core purpose comes first, with the statistic trailing. Efficient overall, though the exact-count-and-date parenthetical is marginally decorative.

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 simple one-parameter lookup with no annotations this is nearly sufficient, but with no output schema the description should indicate what comes back (raw part numbers, ranked list, match metadata). The return shape is left entirely unstated.

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?

Only one parameter with 100% schema description coverage, so the schema already explains it. The description adds nothing about input format or whether the part number must first be normalized via the sibling normalize-pn, which is a meaningful gap given that sibling exists.

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 ('Find') and resource ('substitute / equivalent / cross-referenced part numbers') and names the data source (PartsTable cross-reference graph). This is clearly distinguishable from siblings get-part, search-parts, and validate-pn.

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?

There is no when-to-use guidance: it never says when to reach for this instead of get-part or search-parts, nor any preconditions. The purpose is self-evident from the name, but no alternatives or exclusions are given.

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