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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds genuinely useful behavioral context the annotations do not carry: a per-call price, the x402 payment mechanism, and the fact that billing only occurs on success. It stops short of describing failure modes (e.g., no match) but the cost/auth-adjacent disclosure is real added value.

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?

One front-loaded sentence carries the purpose, source, keys, and return fields; a second short sentence carries pricing. No filler, and the most decision-relevant information (what it looks up and what it returns) comes 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?

There is no output schema, but the description compensates by enumerating the returned data fields, and it discloses the payment model relevant to invocation. Only edge-case behavior (no match, ambiguous name, partial results) is unstated, which is a minor gap for a lookup tool with read-only annotations.

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 100%, so both parameters are fully documented in the schema with their formats (12-character UEI, alternative name lookup). The description only restates that either key may be used, adding no format or precedence detail beyond the schema. Baseline 3 applies.

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 (look up), a specific resource (US federal contractor), the authoritative source (SAM.gov), the lookup keys (UEI or legal business name), and the returned fields (registration status/expiration, CAGE code, exclusion flag, NAICS codes, business types). This is unmistakably distinct from the other verification-style siblings such as check_motor_carrier_safety or verify_healthcare_provider.

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 implies when to use it (any time you need federal-contractor registration data) and notes that UEI or name are acceptable inputs, but it never states when NOT to use it or points to an alternative tool. Usage is inferable rather than explicit.

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