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

With no annotations, the description carries the burden and does reasonably well: it discloses cost ('Free'), the key algorithm (Ed25519), the header it validates (X-GW8-Signature), and the scope (paid responses only). It does not mention key rotation, caching, or whether the key is static, 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?

A single tightly packed sentence: the cost qualifier is front-loaded, then the resource, then the verification target. Nothing is wasted and the most scannable details come first.

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?

No output schema exists, so the description must indicate what comes back — it names the public key and scheme, which is the essential return content, but does not specify the response shape (e.g. whether the scheme string and key are separate fields). For a zero-param, zero-annotation utility this is nearly complete.

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 per the baseline there is nothing the description needs to compensate for. No parameter meaning is missing or misleading.

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 precisely what is returned (Ed25519 public key plus signing scheme) and its purpose, with the header name X-GW8-Signature and the scope 'paid responses'. This distinguishes it from the data-feed siblings such as list_paid_endpoints or get_sample, though it relies on an implied 'get' rather than an explicit verb.

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?

'Free:' and 'on paid responses' imply the context of use — call it to verify response authenticity rather than to fetch market data — but no explicit when-to-use or alternative (e.g. why not just trust the payload) is given. Usage is inferable but not stated.

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