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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, covering the safety profile. The description adds the 'Free, no key' note and details the output contents, which is useful context beyond annotations. It does not contradict annotations. It doesn't describe rate limits or latency, but with annotations covering the core traits, a 3 is appropriate.

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 a single dense sentence that efficiently packs the tool's purpose and output components. It front-loads the primary function ('detailed breach-exposure report') before listing specifics. It's concise without being overly terse, though it could be split into two sentences for readability. Earns its place with no filler.

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 is read-only, has a single well-documented parameter, and no output schema, the description does a good job of explaining what the report includes, which substitutes for an output schema. It covers the key value proposition (breaches, risk, password strength, paste exposures) and notes free access. It doesn't mention pagination or limits, but for a report tool this is acceptable.

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 coverage is 100%: the 'email' parameter is already described in the schema. The tool description doesn't add any extra meaning about the parameter (format, constraints, or how it's used). Baseline 3 is correct when the schema handles the parameter documentation.

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 produces a 'detailed breach-exposure report' for an email address and enumerates the report contents (breach date, records affected, data classes, risk score, password strength, paste exposures). This is specific and unambiguous. It doesn't explicitly contrast with the sibling 'email_breaches', so it's not a 5, but the purpose is well-defined.

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?

There is no guidance on when to choose this tool over the similar 'email_breaches' sibling. The description implies it is the 'detailed' option but never says 'use email_breaches for a simple check' or any alternative. It mentions 'Free, no key' but that's not usage context.

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