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

With no annotations, the description must carry the full burden of behavioral disclosure. It only mentions that the body is discarded, but says nothing about what happens to the other 8 parameters (e.g., ref, city, feed), whether network requests are made for each, or whether it performs format validation instead of live fetching. The description gives no insight into side effects, error behavior, or rate limits, and may actually mislead about the tool's full capabilities.

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 only one sentence, which could be concise if it were complete, but it is under-specified given the tool's complexity. It withholds information about the other parameters and their behaviors, so it prioritizes brevity over utility. A more structured description that maps parameters to their intended checks would be more helpful.

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 tool with 9 parameters, no annotations, and no output schema, this description is far too incomplete. It only addresses the URL case and gives no hints about return values, error handling, or how non-URL parameters are processed. Agents cannot confidently call this tool with anything other than a URL without risking unexpected behavior.

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%, and each parameter is already documented with its purpose (e.g., 'Git ref name; discarded after the shape check'). The description adds no extra meaning beyond what the schema provides. Since the schema does a good job of explaining parameters, a baseline of 3 is appropriate even though the description does not aggregate or contextualize them.

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 it returns HTTP status and content type for a public URL and discards the body. However, it does not explain the tool's broader purpose as a multi-parameter checker, nor does it distinguish itself from similar siblings like 'fetch-status' or 'normalize-url'. The verb+resource is specific but the scope is ambiguous given the 9-parameter schema.

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 provides no guidance on when to use this tool versus alternatives. It does not mention that other tools like 'fetch-status' or 'validate-json' might be more appropriate for specific inputs, nor does it state any prerequisites or exclusions. Agents have no way to decide between this and its siblings.

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