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

Annotations are sparse and partly unhelpful here (readOnlyHint=false on what reads as a reporting call), so the description carries real weight and does deliver: a 24-hour window, the fields reported, the explicit warning that no safety judgment is made, and that the agent must recompute hashes itself. It does not say what happens if no checks exist or how the record is formatted, which are the remaining behavioral gaps.

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, front-loaded with what the caller gets and followed by the critical caveat plus cost/access note. The slightly stylized phrasing ('signed like the facts') costs nothing and every clause carries information.

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 no parameters and no output schema, the description must convey the return shape, and it does at a field level (count, hashes, difference flag, last-check time) together with the trust caveat. It stops short of describing the actual encoding/format or the empty-window behavior, but nothing needed to invoke it correctly is missing.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; baseline applies. The description correctly implies no inputs are needed by emphasizing it is free and keyless.

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 names the exact resource and scope: independent agent checks on PazAIr in the last 24 hours, and enumerates the fields returned (count, hashes seen, difference reported, timestamp of last check). That is far more specific than the bare name 'guestbook'. It never explicitly contrasts itself with the sibling sign_guestbook (the write counterpart), so the read-vs-sign distinction must be inferred.

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 an implicit usage instruction — treat the output as evidence, not a verdict ('It never says "safe"; recompute the expected hashes yourself') — and an access note ('Free, no key'). But there is no explicit when-to-use/when-not guidance and no routing to related verification siblings such as verify, check_agent, witness, or proof_seal, leaving the agent to infer when this is the right evidence source.

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