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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds a useful cost disclosure ('$0.5 USDC') and an output hint, but the mangled 'an object with 17 fields including checkable_fraction, cited' fragment is cryptic and doesn't clearly explain the verdict semantics.

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?

It is short but poorly structured: double punctuation ('?.'), a dangling output fragment, and a price tag appended without context ('$0.5 USDC.'). The information is present but scattered rather than front-loaded and coherent.

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 annotations cover safety, so the description needn't explain returns. But for a paid, nested-object verification tool, the decision logic of 'validity' is left entirely implicit; the description should say more about how validity is judged beyond naming the currency cost.

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%, so the schema already documents claim/terms/reference (albeit with generic boilerplate). The description adds no meaning about what claim or terms should contain, so the baseline 3 is appropriate.

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 question form 'Is this warranty claim valid against these terms?' conveys the core function (validity check of a warranty claim against terms) and names the sibling it is not. However, the phrasing is a question rather than a clear verb+resource statement, and the trailing fragment 'an object with 17 fields including checkable_fraction, cited' clutters rather than clarifies purpose.

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?

It explicitly routes the agent: 'use it rather than `verify_commerce_intent` for warranty claim, not commerce intent.' This names the alternative and the condition that selects it. No further exclusions are given, keeping it at a 4 rather than 5.

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