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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It reveals that the key is public and suggests it is stable ('pin it once'), but it does not mention error cases, response format, or any operational caveats. For a simple read-only fetch, the description adds useful context but lacks depth.

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?

The description is compact and front-loaded with the primary action ('Returns the post-quantum issuer public key'). It uses a few sentences to convey purpose, usage, and rationale without excessive complexity. Structurally clear and efficient.

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?

For a zero-parameter tool with no output schema, the description provides enough context: what the key is, why it matters (trust anchor), and how to use it (pin once). It does not describe the exact data format of the returned key, but that is likely implicit. Overall, the description is complete for its simplicity.

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 has zero parameters, and the input schema is empty. According to the rubric, a baseline of 4 applies when there are no parameters, as the description does not need to explain them. The description correctly focuses on the output and purpose rather than inputs.

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 clearly states the tool's function: 'Returns the post-quantum issuer public key' and explains its role as a trust anchor that countersigns attestations and mints. The verb and resource are specific, but it does not explicitly differentiate from sibling tools like null_prekeys_fetch or robyn_attestation. A clear statement of purpose but no sibling disambiguation.

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 instruction 'Pin it once' implies a usage pattern: fetch the key once and cache it for verification. However, it does not describe when to use this tool versus alternatives or mention any conditions that would make a different tool more appropriate. The guidance is implied rather than explicit.

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