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

Annotations already establish readOnlyHint=true and openWorldHint=true, and the description goes beyond them by disclosing that verification happens offline, that the trust anchor is a specific bundled key, and that the key is published at a well-known URL. It stops short of describing failure modes or what makes verification fail.

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 dense, front-loaded sentences that lead with the action and the checks performed; the reproducibility and key-publication details are useful but slightly burden the second sentence. Nothing is redundant.

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 no explanation, and the annotations carry the safety profile. The description covers the cryptographic scope and both input paths, leaving only edge-case behavior (e.g., malformed receipts, network failure when fetching by id) unspecified.

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, and the description adds genuine semantics: passing an id triggers an internal fetch while passing a receipt object verifies without fetching. That behavioral distinction between the two optional parameters is not evident from the schema alone.

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 (verify) and resource (receipt) and enumerates exactly what is checked: the Ed25519 signature, the output hash, and the id. The phrase 'Send an id to fetch it first' implicitly differentiates it from the sibling get_receipt, which only retrieves.

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?

The description clearly spells out the two mutually exclusive input modes ('Send an id to fetch it first, or the receipt itself'), which is real usage guidance for an agent choosing how to call it. It does not, however, state when verification is unnecessary or how it relates to validate_* siblings.

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