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

The description adds genuinely useful behavioral context not in the annotations: a per-call price of $0.004 USDC charged only on successful calls. However, it never explains why readOnlyHint=false despite an inspection-style operation (presumably the payment/caching side effect) or what the tool does to the target URL. Annotations cover openWorldHint, so the remaining gap is moderate.

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 sentences, front-loaded with the action and the value proposition, followed by the pricing note. No filler, no repetition of the title or name.

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?

With no output schema, the description carries the burden of describing returns, and it does so by enumerating the four result categories and the cost model. It stops short of covering failure/empty-result behavior or whether the inspected page is fetched and cached.

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?

Only one parameter exists and the schema documents it at 100% coverage with its own description. The tool description implies the URL should point at a developer/documentation page but adds no format or constraint detail beyond the schema, so the baseline 3 applies.

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 states a specific verb ('Discover') and resource ('the callable public API behind a developer or documentation page') and then enumerates the exact artifacts produced (base URLs, portals, machine-readable docs, auth docs). This is unambiguous and clearly separable from the preflight/resolve siblings.

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 phrase 'for integration setup' implies the intended context, but there is no explicit when-to-use guidance, no statement of prerequisites (what kind of URL qualifies), and no comparison to alternatives such as domain_preflight or package_preflight. Usage is inferred rather than stated.

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