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

readOnlyHint=true is consistent with a verification operation, so the safety bar is already met and no contradiction exists. The description adds real mechanism (JCS + sha256, signature against a published key), but says nothing about outcome behavior: whether a failed check raises an error or returns a falsy result, what happens with an untrusted/unpublished key, or whether network/key-lookup is involved.

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 sentences, no filler, with the core semantic (what is verified) front-loaded and the input requirement second. Every clause carries information an agent needs.

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?

There is no output schema, so the description is the only place a caller could learn that this returns a pass/fail verdict, an error reason, or the key identity used — and it does not. For a trust/security tool where the caller must act on the result, that omission matters, though the input side is adequately covered.

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 0% and the single parameter is an opaque nested object, so the schema alone tells an agent nothing. The description compensates by enumerating the envelope's required shape as {report, digest, signature}, which is genuinely additive. It stops short of describing encodings or formats for digest and signature, which remain ambiguous.

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+resource (verify a ColdRead report envelope) and specifies the exact check performed: JCS canonicalization + sha256 integrity plus signature against a published ColdRead key. An agent knows precisely what this tool does, but the description never differentiates it from the sibling 'coldread_check', which by name sounds like the same activity.

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 only guidance is 'Pass the whole envelope {report, digest, signature}', which is input-formatting advice rather than a when-to-use rule. With siblings 'coldread_check' and 'coldread_get_report' present, the description gives no condition for choosing this tool over them and no preconditions (e.g., must the report have been fetched first?).

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