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

With no annotations, the description carries the transparency burden. It usefully discloses that the body is discarded, which is a real behavioral trait. It does not mention redirects, failures, rate limits, or how the extra schema parameters relate to actual behavior.

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 short sentences, front-loaded with the core purpose and immediately followed by the key caveat. There is no wasted text.

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 a complex 9-parameter schema and no output schema or annotations, yet the description only addresses the URL use case. It fails to clarify why parameters like city, json, path, zone, and query exist or how they should be used, leaving the tool's full contract ambiguous.

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 baseline is 3. The description adds only the 'URL' context and does not explain the other eight parameters, but the schema already documents each parameter individually.

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: getting HTTP status and content type for a public URL, and it explicitly says the body is discarded. However, it does not distinguish web-fetch from fetch-status or browser-url-ok, and the unusually broad input schema makes the actual scope less clear.

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 when to use the tool: for a public URL when status and content type are needed. It gives no explicit alternatives, exclusions, or guidance about the many sibling tools, so an agent must infer the correct routing.

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