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

No annotations are provided, so the description carries the full burden. It usefully discloses two behavioral traits: the answer comes solely from catalog fitment data, and the result is 'unknown' when no fitment data exists. However, it says nothing about permissions, latency, or whether sku/product_id are alternative identifiers, so significant burden remains unaddressed.

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?

Two short sentences, front-loaded with the core question, followed immediately by the data-source and unknown-result caveats. No filler.

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 read query with no output schema this is nearly adequate: it explains the answer semantics (fit / unknown). But with no annotations and only 33% schema coverage, the missing guidance on the two undocumented identifiers leaves the definition incomplete for correct invocation.

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 only 33%: antenna_model is documented ('Model slug or common name') but sku and product_id are not. The description says nothing about parameters, so it fails to clarify whether sku and product_id are alternate ways to identify the same part or whether both must be supplied. It does not compensate for the coverage 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 states a specific question the tool answers ('Does a part fit a given antenna model?'), which is a clear verb+resource even though it is phrased interrogatively. It is readily distinguishable from siblings like get_quote, resolve_supersession, and search_parts. It stops short of explicitly naming those alternatives.

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 implied: this is the tool to call when you need a fitment answer. The clause 'Answers from the catalog fitment data only' scopes the source but does not say when to prefer this over search_parts or how to handle parts with no fitment entry. No explicit when-to-use/when-not guidance.

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