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

Annotations cover read-only/open-world/idempotency, and the description adds genuinely non-structured context: per-call price ($0.005 USDC), wallet charging within budget caps, the product registry, and an explicit prompt-injection warning that results are third-party data. It does not explain the non-idempotent billing implication (repeat calls cost again), which would have completed the picture.

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?

Four short sentences, front-loaded with purpose, followed by price, payment mechanics, and provenance. Every sentence carries information; no filler.

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 paid read-only fact lookup with no output schema, the description covers return categories, cost, and data trust. It omits the meaning of the version parameter and any sense of response shape, which leaves minor gaps for an agent deciding how to call it.

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 coverage is 67%; confirm_over_cap and name are documented in the schema. The description's 'only within the budget caps' adds relevant context for confirm_over_cap, but the version parameter remains completely undefined in both schema and description (does it pin, filter, or default?), so it does not fully compensate.

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 resource (an npm package) and enumerates the fact categories returned: versions, maintainers, downloads, dependencies. No sibling is remotely similar (the others are domain/ski/company lookups), so no differentiation is needed, but it also does not situate itself against 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?

There is no when-to-use guidance at all. It never says what to do if the package name is wrong, whether version is optional or filters results, or when an agent should prefer another lookup; the only conditional text is about payment, not usage.

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