breachLatest

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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds a genuinely useful behavioral fact beyond the annotations – that the endpoint is free and requires no API key – which directly answers an agent's auth/setup question.

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 short sentences, with the action and its scope front-loaded and the auth/cost caveat following immediately. No filler, no redundancy with the title or schema.

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 parameterless, read-only tool the description covers the essential decision inputs: what it returns conceptually and that no key is needed. There is no output schema, so a sentence sketching the returned breach fields would have been a nice addition, but nothing critical to correct invocation is missing.

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 tool takes zero parameters, so per the rubric the baseline is 4. The description neither needs nor provides per-parameter detail, and nothing about invocation is ambiguous.

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?

States a specific verb and resource ('Get the most recently added data breach') and names the data source (HaveIBeenPwned), which is enough to distinguish it from siblings like breachList or breachSearch. However, it does not explicitly contrast itself with the closely related breachGet/breachList tools, so it falls short of full sibling differentiation.

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 word 'Latest' plus 'Free endpoint, no API key required' implies the scenario in which this tool is attractive (a quick, zero-config peek at the newest breach). But there is no explicit when-to-use guidance and no mention of the alternative tools (breachList, breachSearch, breachGet) that cover historical or targeted queries.

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