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

Annotations already indicate not read-only and not idempotent, and the description adds substantial behavioral detail: it bypasses human interaction, never solves CAPTCHAs, enforces a 3-scans-per-host-per-day limit, and returns failure modes with instructions. This goes well beyond the annotations without contradicting them.

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?

Three dense sentences front-load the core action, then cover return value, failure modes, rate limits, and the no-CAPTCHA behavior. Every sentence earns its place with no fluff.

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 mutating, rate-limited, stateful operation with no output schema, the description still provides return values (scan id, results URL), error conditions, prerequisites, and behavioral constraints. An agent has enough to know when to call it and what to expect.

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%, so the single url parameter is already fully documented with format and example. The description adds the domain-ownership context and public-page requirement, but the schema already carries the essential semantics, so a baseline 3 is appropriate.

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: verifies domain ownership and queues a Playwright probe that performs signup/acceptance/API key minting. The 'Step 2' marker and reference to readiness_get_verification_token clearly position it against the sibling tools readiness_get_scan and readiness_get_verification_token.

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?

Explicitly frames this as Step 2 after obtaining the verification token, and specifies the prerequisite that the domain must carry that token via DNS TXT, meta tag, or .well-known. It does not explicitly say 'use readiness_get_scan to poll', but the workflow context and return values make the intended usage clear.

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