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

Annotations already establish read-only, idempotent, non-destructive, closed-world behavior, and the description adds substantive context beyond them: the complete shape of a match response (per-claim evidential states, capture tier and caveat, signed verdict, Bitcoin timestamp), the precise meaning of a no-match, and the crucial limitation that it never asserts content is true. Free/no-auth is also disclosed.

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?

Front-loaded with purpose and method in the first two sentences, then return-shape and caveats. Dense but every clause carries information; the parenthetical enumeration of evidential states is the only slightly weighty stretch, though it is genuinely useful.

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 a one-parameter schema, no output schema, and a read-only annotation profile, the description fully covers what an agent needs: what to send, where to compute it, what comes back on a hit and a miss, and the limits of the claim. Nothing material is missing.

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 single parameter has 100% schema coverage ('SHA-256 of the exact file bytes, 64 hex characters'), so the baseline is 3. The description improves on this by stressing local computation, that the file itself is never transmitted, and by warning that re-encoding changes the hash — meaningful semantic framing rather than restating the 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 (check whether) and resource (video/audio/image file byte-for-byte registered by a publisher), and pins the exact identity mechanism (SHA-256). Clearly distinguishable from siblings like verify_proof or validate, which are not the same operation.

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?

Explicitly tells the agent the precondition (compute the SHA-256 locally; the file is not sent), the interpretation rules (no match means not registered and says nothing either way; a re-encoded copy has a different hash), and names the alternative for full file checks (POST /verify-media upload). This is exactly the when/when-not/alternative coverage the dimension asks for.

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