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

Annotations already establish readOnlyHint=true, and the description adds real behavioral value on top: it discloses what is returned (signed announcements plus the public key) and, importantly, that the server itself should not be trusted for verification. That trust caveat is exactly the kind of context annotations cannot express. It stops short of describing failure modes or response shape.

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 tight sentences, front-loaded with the purpose and followed immediately by the return and trust caveat. Every sentence earns its place with no 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?

With no output schema, the description compensates by naming what comes back (signed announcements and public key) and how to use it. A bit more on response format or error behavior would make it fully self-contained, but an agent has enough to call and act on it correctly.

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; the baseline for a no-argument tool applies. The description spends its words on behavior rather than inventing parameter detail, which 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 description pairs a specific verb ("Check whether...really does") with a specific resource (messages claiming to come from the operator), so the agent knows exactly what authenticity question is answered. It does not explicitly contrast itself with similarly named siblings like project100_stone_verify or project100_seal_proof, but the resource is distinct enough to route correctly.

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 a clear directive on how to treat the result ("verify the signature offline rather than trusting this server"), which is genuine usage guidance. However, it never states when to reach for this tool versus alternatives, nor any precondition for invoking it, so usage remains only implied.

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