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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds genuinely non-derivable behavior: a 0.01 USDC charge on Base x402 and the X-Provider-Key header for customer-owned credentials. It stops short of describing what comes back for flagged duplicates or how partial/fuzzy overlap is treated.

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 tight sentences with the operation front-loaded and the billing/auth caveats trailing. Nothing redundant or padded.

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 one-parameter read-only hashing tool with no output schema, the description covers purpose, cost, and auth, which is most of what an agent needs. It leaves open the input encoding and the shape of the duplicate-flag result, which matter for correct invocation.

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?

One parameter at 100% schema coverage, so the baseline is 3. However, the schema description defers format to 'the operation description' and the description never supplies it — 'documents' is typed as a string but described plurally, leaving the actual encoding (single blob vs. serialized list) unstated.

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?

Specific verb and resource: compute SHA-256 hashes of caller-provided text snippets and flag exact duplicates. That operation is clearly distinct from the nearest brain siblings (knowledge_search, text_chunker). It does not explicitly name an alternative, so it falls just short of 5.

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 description never says when to reach for this tool, when not to, or which sibling to use instead (e.g. chunker before hashing). Payment and credential details are present, but no usage routing.

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