Latest CISA Known Exploited Vulnerabilities (filter by days, vendor, product, ransomware use) with due dates, required action and EPSS score joined. Price: $0.002 USDC per call, paid with x402 on Base.
| Name | Required | Description | Default |
|---|---|---|---|
| days | No | Added to KEV within the last N days (default 30, max 3650) | |
| vendor | No | Vendor name contains, e.g. Microsoft | |
| product | No | Product name contains, e.g. Exchange | |
| maxItems | No | Default 50, max 100 | |
| ransomware | No | Known ransomware campaign use |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries full burden; it does usefully disclose the paid-call requirement ($0.002 USDC via x402 on Base) and that results are enriched with EPSS scores. However it says nothing about rate limits, error behavior, or how the paid flow must be handled before calling.
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?
Two sentences, front-loaded with the resource and filters, then the cost. Little waste, though the pricing sentence could be separated more clearly as preconditions.
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 and no annotations, the description compensates reasonably by naming returned fields (due dates, required action, EPSS score). Remaining gaps are the paid-call mechanics and result-set limits, the latter partly covered by maxItems in the schema.
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 baseline is 3; the schema already documents defaults and max values for days, maxItems, vendor, product and ransomware. The description adds no syntax detail (e.g. exact matching versus contains, ransomware value format) beyond what the schema states.
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?
States a specific resource (CISA Known Exploited Vulnerabilities) plus its filter axes, which an agent can distinguish from generic CVE lookup siblings like cve_cve. It never names a sibling tool explicitly, so the differentiation is inferred rather than stated.
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 parenthetical lists filter options but gives no guidance on when to pick this over cve_cve or cve_packages, no prerequisites, and no exclusions. An agent must guess the boundary between the three cve_* tools.
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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