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

With no annotations, the description carries full burden. It discloses that the tool is free, rate-limited, and returns a subset of the full analysis. It doesn't explicitly state read-only behavior, but 'preview' implies it. The rate limit is a key behavioral trait that is disclosed.

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 short and front-loaded with the most important trait ('Free') and the scope ('headline'). Every sentence adds value—no fluff. The structure is direct and easy to parse.

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 single-parameter preview tool with no output schema, the description covers the key behavioral facts (free, rate-limited, subset of results) and the returned content. It lacks parameter documentation, but that is already penalized in parameter_semantics. Overall, the description is sufficient for basic invocation intent.

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 schema has 0% coverage (no description for the url parameter), and the tool description does not mention the parameter at all. An agent must infer that 'url' is a web address, but receives no guidance on format, validation, or constraints. The description fails to compensate for the minimal schema.

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 'preview' and the resource 'access posture', and differentiates it from the sibling (page_posture) by explicitly limiting the output to the 'headline' (verdict, confidence, field schema, one evidence line, price) versus the full report. This makes its purpose unambiguous.

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?

It implies usage for quick, free checks by contrasting with the full report and mentioning the price of the full report. It doesn't explicitly name the alternative or state when NOT to use it, but the context is clear enough for an agent to infer the intended use case.

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