Query US CISA Known Exploited Vulnerabilities (KEV) Catalog for active in-the-wild exploitation, mandatory federal patch due dates, and ransomware usage.
| Name | Required | Description | Default |
|---|---|---|---|
| cve | No | CVE identifier (e.g. CVE-2024-3094, CVE-2021-44228) | |
| limit | No | Max KEV records to return (default 10) | |
| vendor | No | Vendor or product keyword filter (e.g. Microsoft, Linux, Cisco) |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is covered structurally. The description usefully signals that this is authoritative federal KEV data with mandatory remediation dates and ransomware flags, but adds nothing about result volume, ordering, or how the filter parameters combine.
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?
A single front-loaded sentence with no filler; the resource and the three data facets an agent gets back are all stated up front. Nothing could be removed without losing signal.
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 three-optional-parameter, read-only lookup with no output schema and clear annotations, the description is sufficient to select and invoke the tool. The remaining shortfall is the missing routing guidance versus the closely related CVE and exploit-score siblings.
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 the schema already carries the semantics of cve, vendor, and limit, and the baseline here is 3. The description adds a small amount of framing by characterizing the query domain (exploited vulnerabilities, patch due dates), but does not explain that the parameters are optional filters or how they interact.
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?
A specific verb ("Query") plus a named authoritative resource (CISA KEV Catalog), and it enumerates the data facets returned: exploitation status, federal patch due dates, and ransomware usage. It does not name or differentiate itself from near-siblings such as epss_exploit_score or security_cve_audit, so an agent must infer the split itself.
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 by the enumerated data facets — an agent can guess it is for checking whether a CVE is actively exploited and for patch prioritization. There is no explicit when-to-use, when-not-to-use, or statement of how this differs from the exploit-score and CVE-audit siblings, which is the main gap given the crowded neighborhood.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.