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

Beyond the annotations, the description discloses data sources, returned advisory details, pricing ($0.02 USDC per successful call via x402 on Solana), and an alternate HTTPS endpoint. These are important operational details an agent would not get from the readOnly/openWorld/idempotent annotations alone.

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 purpose is front-loaded and the description is generally efficient, but it is dense with ecosystem and source enumerations that partly duplicate the schema. It remains readable and relevant, with only mild 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?

With no output schema, the description compensates by naming the advertised return fields: advisory id, CVE aliases, severity, CVSS vectors, CWEs, fixed versions, heuristic upgrade, and links. It also covers pricing, endpoint, and batch routing, making it complete enough for correct invocation.

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 parameter meaning is already documented in the schema. The description reinforces single-package scope and supported ecosystems, but adds little parameter-specific syntax or selection guidance beyond what the schema provides.

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 and scope: known vulnerabilities for ONE package version from OSV.dev, with concrete returned fields and supported ecosystems. It also distinguishes this tool from batch usage by saying to use POST for a whole dependency list or lockfile, which separates it from osv_scan_batch.

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?

It clearly indicates the single-package use case and names the alternative for whole dependency lists or lockfiles. However, it does not explicitly compare against adjacent siblings such as cve_lookup or package_risk, so the guidance is clear but not fully exhaustive.

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