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

Beyond the read-only and open-world annotations, the description discloses that the call is one anonymous GET with no login, limited to the public home page. It also adds non-obvious operational details: pricing ($0.002 USDC per successful call via x402 on Base, Solana, or Arc) and that failed calls are not charged.

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 three tight sentences: first the core behavior, then the scope limitation, then the pricing. It is front-loaded with the most important capability and has no wasted wording.

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 one-parameter read-only tool with an output schema, the description covers what is checked, what is excluded, how the request is made (anonymous GET), and the payment model. Nothing essential for 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 input schema has 100% description coverage for the single domain parameter, so the schema already explains the parameter semantics. The description does not add syntax or format details beyond referring to the 'site', which is adequate given the high schema coverage.

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 ('Lists') and resource ('cookies a site sets on its public home page') along with the exact fields reported (Secure, HttpOnly, SameSite) and the flagging behavior. The scope limitation to the public home page distinguishes it from broader crawling or authenticated-session tools.

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 clearly describes the context of use and explicitly states what is out of scope: cookies set after login or on other pages are not seen. However, it does not name alternative tools or explicitly route the agent between this and sibling security tools.

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