guess_cpes

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds behavioral context by explaining the default base URL (https://cpe-guesser.cve-search.org) and the VULNMCP_CPE_GUESSER_URL environment variable for override. This is useful configuration information but does not disclose details like response behavior or edge cases. With annotations, this extra context earns a 3, though richer operational details would push higher.

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 two sentences: the first clearly states the purpose, and the second provides necessary configuration details about the default URL and environment variable. Every sentence earns its place, and it is appropriately sized for the tool's simplicity.

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 tool with one parameter, full annotations, and an output schema, the description provides sufficient context. It includes purpose and configuration details. The output schema already handles return values, and annotations handle safety. There is no missing critical information that would prevent correct tool selection or invocation.

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%: the input schema already describes the 'query' parameter as 'A list of product keywords (e.g. ["outlook", "connector"]).' The description does not add additional parameter semantics beyond this. Per the rubric, when schema coverage is high, the baseline is 3 even with no extra param information, and no extra value is added here.

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 clearly states the tool 'Guess CPE values from product-related keywords using cpe-guesser.' This is a specific verb (guess) + resource (CPE values) + method (from keywords using cpe-guesser). It is easily distinguishable from sibling tools like search_vulnerabilities or classify_severity, which involve different operations.

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 implies usage: when you have product keywords and need CPE values, this tool guesses them. However, it provides no explicit when-to-use versus alternatives, no exclusions, and does not reference sibling tools. Usage context is clear but not elaborated, so it falls under 'implied usage.'

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