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

With no annotations, the description must carry the full behavioral burden, but it only discloses that the body is discarded. It does not mention behavior regarding redirects, authentication, rate limits, or what is returned beyond status and content type. Moreover, the schema includes 9 parameters (e.g., city, zone, query) that are completely unrelated to the description, suggesting the tool may have additional purposes that are left unstated. This lack of disclosure creates confusion and undermines transparency.

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 concise and front-loaded, stating the main purpose in one sentence and adding the body-discard behavior in a second. No wasted words. However, given the complexity of the schema (9 parameters), the description might benefit from a brief mention of the broader functionality, but as written it is appropriately short and focused.

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?

The tool has 9 parameters, no output schema, and no annotations. The description covers only one use case (fetching a URL), while the parameters suggest additional functions like timezone lookups, JSON validation, and search-length checks. The description fails to explain these other capabilities or how they interact, leaving an agent unable to determine when to use this tool for those cases. For a tool with this complexity, the description is incomplete.

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 schema description coverage is 100%, so each parameter has its own description in the schema. The tool description does not add any parameter-specific meaning beyond that. While the schema descriptions clarify individual parameters (e.g., 'discarded after the shape check'), the tool description does not integrate them into an overall understanding. Baseline 3 applies because the schema already documents parameters adequately, and the description does not need to compensate.

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 clearly states the core action: fetching a public URL to obtain HTTP status and content type, with body discarded. It is specific enough to distinguish from generic tools, though it does not explicitly contrast with siblings like fetch-status or normalize-url. The purpose is unambiguous and uses a specific verb and resource.

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 implies usage for checking HTTP status and content type of a public URL, but it does not provide explicit guidance on when to use this tool versus alternatives like fetch-status, browser-url-ok, or normalize-url. There is no mention of prerequisites, exclusions, or scenarios where a different tool would be preferable. The guidance is minimal but not misleading.

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