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

No annotations exist, so the description carries the full burden. It discloses the cost ('$0.008 USDC per call via x402 on Base'), which is a genuine gating operational fact beyond plain READ behavior. It omits auth/rate-limit details, but the cost disclosure plus OSV-source context covers the most important behavioral concerns.

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?

Three sentences with no filler: purpose first, then return contents and version semantics, then usage guidance, and finally cost. Every sentence earns its place and the most decision-relevant info is front-loaded.

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?

With 3 fully documented parameters and no output schema, the description covers purpose, return contents, usage context, and cost. The return payload is partially described (fields listed) which suffices for an agent to judge the result. Only minor operational detail like response size is absent.

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% (baseline 3), and the description adds real value beyond it by explaining the version parameter behavior: passing it narrows advisories to that version while omitting it shows all. This interpretation is not in the schema and materially changes the call.

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 states a specific resource ('advisories for a package from OSV') and tells exactly what is returned ('advisory ids, severity, summary and the versions that fix each one'). This clears distinguishes it from siblings like package_info and package_audit by its vulnerability-specific scope.

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?

Explicitly states when to use it ('before pinning a dependency or when auditing a lockfile') and explains the semantic difference between passing and omitting the version parameter. It does not name alternatives or add exclusions, but the context is clear enough for an agent to choose it correctly.

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