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

With no annotations, the description carries the burden of behavioral disclosure. It discloses the check scope, the origin behavior, and that the operation is free and anonymous. It does not describe the output format or whether network requests are made explicitly, but the intended behavior is sufficiently transparent for a validation tool.

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 two sentences with no filler. The core action and target files are front-loaded, and the usage hint plus free/anonymous note are compact and useful.

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, simple validation tool, the description covers what is checked, how to provide input, and key operational traits. It does not explain the return value, but with no output schema and a straightforward validation purpose, the described behavior is enough for correct selection and invocation.

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 description coverage is 100%, so the schema already documents the single parameter. The description adds modest context by restating that the origin is used and that any URL on the site works, but it does not materially expand beyond the schema. 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?

The description names a specific verb ('Check') and concrete resources (llms.txt, agent.json, robots.txt), making the tool's purpose unambiguous. It also explains what aspect is checked ('presence and validity') and that any site URL works, which distinguishes it from the 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?

The description gives clear usage direction: provide any URL on the site, and the origin will be checked. It does not explicitly name alternatives or when-not-to-use, but the sibling tools are distinct enough that no exclusion is needed. 'Free, anonymous' also signals there is no auth or cost barrier.

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