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

The description adds valuable behavioral context beyond annotations: normalization rules (digits-only phone, lowercased trimmed email), no lookup/storage side effects, price, and the requirement for explicit wallet authorization. This complements the annotations without contradicting them.

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: purpose first, then normalization details, then side-effect and pricing caveats. Every sentence contributes essential information with no redundancy.

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?

The core purpose and required input semantics are covered well, and the description notes payment requirements. However, with no output schema, the return value is not explicitly described, and the optional protocol parameters are left unexplained, making the definition incomplete for advanced or paid invocations.

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?

With 0% schema description coverage, the description compensates for the core input fields by explaining phone, email, zip, and product/service type normalization. However, it does not explain the optional protocol parameters (result_expires, idempotency_key, result_signature, payment_signature), though it does mention wallet authorization generally.

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 and resource: 'Build a stable SHA-256 fingerprint' from contact fields. It clearly states the purpose ('detecting the same contact submitting more than once') and distinguishes itself from sibling tools by emphasizing it does not look up or store anything.

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 gives clear context for when to use the tool: when detecting duplicate contact submissions via a normalized fingerprint. It also notes limitations ('Normalization only', 'does not look up or store anything'), but it does not explicitly name alternatives or exclusion criteria.

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