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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the safety profile is known. The description adds useful behavioral context beyond that: results are sorted newest first and the summary includes EPSS, CVSS, and due date. It does not discuss pagination or rate limits, but those are less critical for this simple read-only feed.

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 sentence that front-loads the action and resource, then packs ordering and key result fields without wasted words. Every part earns its place.

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 tool with one optional parameter, no output schema, and read-only/idempotent annotations, the description is complete: it names the data source, ordering, and summary fields. Nothing essential is missing for an agent to select and invoke it correctly.

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?

The only parameter, limit, is fully documented in the schema with type, default, range, and description, so schema coverage is 100%. The tool description does not add parameter-specific semantics, but it also does not need to; 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 uses a specific verb ('List') with a precise resource ('CVEs most recently added to CISA's Known Exploited Vulnerabilities catalog') and states ordering ('newest first') and included fields. This clearly distinguishes it from siblings like cve_kev_lookup, which implies lookup by a specific CVE rather than a feed.

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 use is implied by 'most recently added' and 'newest first': an agent can infer to use this when the user wants recent KEV entries. However, the description does not explicitly state when not to use it or name alternatives such as cve_kev_lookup for specific CVE lookups.

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