breachList

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

No annotations are provided, so the description alone must convey behavioral traits. It correctly notes that the tool is free and requires no API key. However, it omits details on rate limits, pagination, or data freshness, leaving some behavioral aspects unclear.

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 extremely concise at two sentences, with the purpose stated first and an additional useful detail (free, no key) in the second sentence. Every word serves a purpose, achieving optimal conciseness.

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?

Given the tool's simplicity (one optional parameter, no output schema), the description provides sufficient context: it lists all breaches, filters by domain optionally, and notes the free access. No critical gaps are present, though it could optionally specify the output format or scale.

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% for the single optional 'domain' parameter, with the description repeating the schema's example. As the schema already fully describes the parameter, the description adds no extra semantic value, meeting the baseline of 3.

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 verb 'List', resource 'all known data breaches', and source 'HaveIBeenPwned', with an optional domain filter. While it distinguishes from siblings like breachGet and breachSearch, it does not explicitly differentiate from them.

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 mentions 'Free endpoint, no API key required', providing some context on accessibility. However, it lacks explicit guidance on when to use breachList versus related tools such as breachSearch or breachLatest, and does not mention any restrictions or prerequisites.

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