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

With no annotations provided, the description carries the full burden and does disclose meaningful behavior: it lists what is scanned, restricts the operation to free public URLs, and explicitly states that page text is not returned. It stops short of describing error behavior or side effects, but for a read-only preflight scan this is reasonably transparent.

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, front-loaded sentence conveys the tool's purpose and a key exclusion with no filler. Every word earns its place.

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 two-parameter tool with no output schema, the description covers the main purpose and output categories but omits parameter semantics for maxChars and usage guidance relative to the sibling tool. It is serviceable but not 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?

Schema description coverage is 0%, so the description must compensate. It gives context for the URL parameter ('free public URL'), but says nothing about maxChars, which the schema leaves undefined beyond type and bounds. This is a significant gap for a tool with only two parameters.

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 uses a specific verb ('scan') and identifies both the resource type (free public URLs) and the specific checks performed (fetchability, provenance, hash, injection indicators). The closing 'Does not return page text' also helps separate it from the sibling proof_fetch_offer, though the sibling is not named.

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?

There is no explicit statement of when to choose this tool over proof_fetch_offer. The only hint is the negative 'Does not return page text,' which implies the alternate tool may return page text, but no positive use case, prerequisite, or explicit alternative is provided.

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