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

The annotations already cover readOnly, openWorld, idempotent, and non-destructive behavior. The description adds useful context beyond those annotations by specifying that the check is based only on the fetched robots.txt and explicitly excluding server-side blocking. No contradiction with annotations.

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 result, then followed by a useful caveat. Every sentence earns its place, and the crawler list is compact but specific.

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, read-only, idempotent tool, the description is complete enough to invoke correctly: it defines the input, the output type, the URL behavior, and a key limitation. No output schema is present, but the allowed/blocked report is adequately described.

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 single parameter `domain` is fully documented in the schema with an example and the exact URL pattern `https://<domain>/robots.txt`. Since schema coverage is 100%, the description does not need to add more parameter detail, and it does not meaningfully go beyond what the schema already states.

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 names a specific operation (fetches a domain's robots.txt) and a specific output (reports which known AI crawlers are allowed or blocked), listing concrete crawler examples. This makes the tool's purpose clear and distinct from the other unrelated sibling 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 provides a clear boundary: the result reflects robots.txt only, not server-side blocking, so an agent knows not to use it for actual access checks. It does not name a sibling alternative or state explicit when-to-use conditions, so it stops short of a 5.

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