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

With no annotations, the description carries the full burden. It does disclose key behavioral traits: signature confirmation, the specific fields verified, accessibility to anyone holding the receipt, and a privacy guarantee ('reveals nothing else'). However, it does not describe what happens on invalid signature (error vs. false return) or the return shape, which is a notable gap for an agent.

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?

Four short sentences, all informative. The main verb and object are front-loaded, and the privacy guarantee is a compact final sentence. No redundant phrases or 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?

The description covers purpose, parameter source, and privacy, but does not specify the return value or behavior on invalid signatures. Since there is no output schema, the description should be more explicit about what the agent receives after verification, especially in failure cases.

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 baseline is 3. The description adds value beyond the schema by listing the receipt fields that are verified (provider, price, fee, hashes), which clues the agent into the expected structure and semantics of the receipt object.

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 verb ('Check/Confirms'), a specific resource ('a receipt returned by call()'), and enumerates exactly what is confirmed (provider, price, fee, and hashes). This clearly differentiates it from siblings like call, discover, and dispute, which all have distinct purposes.

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 gives clear context: use this when you hold a receipt returned by call() and need to confirm its authenticity. It does not explicitly name alternatives or describe when not to use it, so it falls short of a 5, but the purpose is specific enough that an agent would not confuse it with siblings.

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