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

No annotations are provided, so the description carries the full burden, and it does disclose meaningful behavior: it is a reporting/read operation, it returns the digests and key material so the caller can verify independently rather than trusting the server's verdict, and it explains the threat model (mirror/cache/snapshot paths). It omits failure semantics (does it throw or report invalid) and any auth or rate-limit requirements.

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 the core action followed by the usage condition. Every clause carries information, though the second sentence is somewhat indirect ('when the answer matters enough that the provenance of the source does') before it reaches the concrete mirror/cache case.

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 annotations and no output schema, the description does the heavy lifting well by naming the returned artifacts (digests, key material) so the agent knows what to expect. Given the tool is a parameterless read/report operation, what remains missing is mostly edge behavior: what an invalid signature looks like in the response and whether it can fail.

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 the schema covers nothing and the baseline of 4 applies. The description correctly implies the server already knows which corpus to inspect, requiring no caller-supplied identifiers, which is consistent with the empty input schema.

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 and resource: it reports whether the server's fetched documents carry a valid Ed25519 signature from Lunara Society, and what it returns (digests and key material). The scoping to 'documents this server fetched' is precise. It does not, however, differentiate itself from the potentially overlapping sibling lunara_verify, which an agent could easily confuse with a signature-integrity check.

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?

Gives an explicit trigger condition: use it when the provenance of the source matters, specifically for a corpus served from a mirror, cache, or snapshot, because transport security from the original fetch does not cover those paths. No alternative sibling is named as a when-to-use-this-instead, so routing against lunara_verify is left to inference.

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