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

With no annotations supplied, the description carries the behavioral burden and does it well: it discloses the $0.001 USDC x402 charge, states that unknown ids and upstream errors are not charged, and names the upstream sources and license. It does not describe response shape beyond enumerating fields, but the pricing and error-billing behavior are the operationally important details here.

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 core capability is front-loaded in the first clause, with return contents listed immediately after and cost placed last. The field enumeration is long but each item (aliases, affected ranges, severity, CVSS) tells the agent something about whether the response will answer its question.

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 single-id lookup with no output schema, the description adequately previews the return payload — aliases, affected packages and ranges, references, credits, database_specific, normalized severity and computed CVSS. The remaining gap is that the pitfalls of the narrow id pattern and any rate limits or truncation behavior are not mentioned.

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 100% and there is only one parameter, whose description already says 'OSV id or CVE alias'. The description adds the concrete accepted id prefixes, which is genuine extra meaning about what forms are valid, but the pattern constraint and required-ness are fully handled by 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 resource — the full OSV record for a single vulnerability id — and enumerates the accepted id namespaces (GHSA, CVE, PYSEC, GO, RUSTSEC, OSV), so it is clearly a per-id lookup rather than the package-level sibling calls. It never explicitly names package_advisories as the alternative, so it stops short of full sibling differentiation.

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?

Usage is only implied: it is clear you call this once you have a vulnerability id, and the note that unknown ids are not charged encourages trying uncertain ids. There is no statement of when to prefer this over package_advisories or manifest_audit, which are the natural entry points for the same data.

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