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

Annotations already cover the safety profile (readOnlyHint, destructiveHint=false, openWorldHint), so the bar is lower; the description adds real value by disclosing the verified-vs-unverified catalog boundary, the signed receipt, and the four-value decision taxonomy. It does not mention latency, rate limits, or failure modes, keeping it from a 5.

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?

The purpose and usage triggers are correctly front-loaded, but the middle is a single sprawling sentence enumerating every catalog category and sub-item, which is far denser than an agent needs to select the tool. The return-value sentence is useful, but the taxonomy list bloats the definition.

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 an output schema present, return values need not be enumerated, yet the description still summarizes decisions, caveats, and multi-candidate behavior, and it explains the out-of-catalog fallback. An agent has enough to call it correctly; only the absence of any exclusion/alternative guidance leaves a small gap.

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 description coverage is 100%, so the schema already documents each field with examples, including the id-based substitutes. The description adds no additional semantics for existing/candidate/detail or the *_id parameters, so the baseline 3 applies.

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+resource question ('Will this exact part or accessory work with that exact device?') and immediately frames the two-input comparison. It is clearly distinguishable from siblings like check_fit, check_batch, or find_parts because it names both sides of the pair being compared.

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?

'Use before recommending or buying' gives an explicit trigger condition and the query even quotes user phrasing. It never names an alternative tool or states when NOT to use this one (e.g. batch cases belonging to check_batch), so it falls short of a 5.

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