epss_score_lookup

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does not mention what happens for unknown CVEs, the exact return format (e.g., float 0-1 vs percentage), or any rate limits or external API dependencies. The 'FIRST' qualifier hints at behavior but is insufficient for a tool with zero annotation coverage.

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 with no fluff. The action is front-loaded, and the EPSS explanation earns its place by clarifying why the score matters. Every word contributes to understanding.

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 simple one-parameter read-only lookup, the description is mostly complete: it names the resource, the input, and the output type ('probability score'). However, with no output schema, it could be more explicit about the return format and error behavior. Still, the tool is simple enough that an agent can likely call it correctly based on this description.

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 single parameter cve_id is already documented with an example. The description adds contextual meaning about EPSS but does not provide additional parameter syntax or format details beyond what the schema already offers, matching the baseline for high schema coverage.

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 ('Get') and resource ('FIRST EPSS probability score for a CVE'), clearly distinguishing it from the sibling epss_bulk_check by emphasizing 'FIRST'. It also explains what EPSS is, leaving no ambiguity about the tool's function.

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 description states a clear use case ('essential for CVE prioritization beyond raw CVSS scores') but does not explicitly mention when to use this tool versus alternatives like epss_bulk_check or nvd_cve_lookup. No exclusions or alternative routing are provided, so usage guidance is implied rather than explicit.

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