cve_kev_lookupCheck whether a CVE is in CISA's Known Exploited Vulnerabilities (KEV) catalog; if so return vendor, product, date added, federal due date, known ransomware use, EPSS probability/percentile, CVSS score/severity/vector, CWE and required action.
| Name | Required | Description | Default |
|---|---|---|---|
| cve_id | Yes | CVE identifier, e.g. "CVE-2021-44228" |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description discloses conditional behavior: enriched details are returned only if the CVE is in the KEV catalog. It also lists the returned fields, which is valuable because no output schema exists, while the annotations already cover read-only and idempotent safety. The negative-case response is not explicitly specified, but this is a minor gap for a simple read-only lookup.
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 description is a single dense sentence with no filler, tautology, or repetition of the input schema. The action and resource are front-loaded, and every listed return field earns its place by informing the agent of the output shape.
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 one-parameter, read-only lookup with no output schema, the description covers the tool's purpose and the full set of returned fields. It is sufficient for selection and invocation, though it could be more complete with an explicit not-found response description and a pointer to the latest_kev sibling.
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%, and the schema already provides the parameter name, type, pattern, and an example. The description adds no additional parameter-level meaning beyond identifying the tool as CVE-focused, so the baseline score of 3 is appropriate.
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 begins with a specific verb ('Check whether') and a specific resource ('CISA's Known Exploited Vulnerabilities (KEV) catalog'), and the per-CVE scope is clear from both the tool name and input schema. It is easily distinguished from siblings like latest_kev, which imply a bulk or latest-entry listing, even though that sibling is not named.
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?
The intended usage is implied: use this when you have a CVE identifier and need to know whether it is in the KEV catalog. However, the description gives no explicit when-to-use guidance, no exclusions, and does not mention alternatives such as latest_kev for browsing recent KEV entries.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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