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

Beyond the readOnly/idempotent/non-destructive annotations, the description discloses what the response contains (flagged, highest severity, advisories, release, scripts, downloads, name-squat flags), the billing model (0.02 USDC via x402 on listed chains), and the important cost nuance that 404 or 503 responses are not charged. That billing and failure-cost context is exactly the kind of behavioral detail annotations cannot carry.

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 trigger condition is front-loaded in the first clause, followed by return fields and then billing. It is dense but every sentence carries usable information; the payment-rail enumeration is slightly long but relevant to callers paying per use.

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 an output schema present, the description needn't explain return values, yet it summarizes them and covers cost and non-charged failures. It stops short of noting behavior on other error codes or whether script/download fields indicate supply-chain risk, which a cautious agent might want.

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%, with name, version, and ecosystem each described in the input schema, including the latest-version default. The description reinforces that matching is on the exact version but adds no syntax or format detail beyond the schema, so the baseline of 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?

The description names a specific verb and resource ('know if an npm or PyPI version has a published advisory') and immediately scopes it to exact-version OSV advisories, which separates it cleanly from nearby siblings like get_claim_check, get_honeypot_check, and get_sol_token_check. An agent can pick this tool without opening the schema.

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?

'Use when an agent needs to know if an npm or PyPI version has a published advisory' gives a clear triggering condition, and the ecosystem parameter narrows the domain. It does not name an alternative tool or state when not to use it, but the ecosystem is narrow enough that no obvious conflict exists among siblings.

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