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

With no annotations provided, the description carries the full burden and does disclose key behavior: it only returns HTTP status and content type, and the body is discarded. This prevents the agent from expecting full page content. It does not mention redirects or timeouts, but the most important behavioral trait is clearly stated.

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 exceptionally concise: two short sentences with the core output and key caveat front-loaded. There is no filler or redundancy, and every word contributes to the meaning.

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 nine optional parameters, but the description only explains one aspect (URL checking) and does not address the presence of city, json, query, zone, path, and other parameters that the schema often marks as 'discarded'. Without an output schema or examples, the agent lacks enough context to confidently decide which parameters are relevant and how the tool behaves in different invocation patterns.

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 minimal meaning beyond the schema, merely confirming that a 'public URL' is the relevant input. It does not clarify how the other eight parameters relate to the core fetch behavior, but the schema descriptions already document 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 states the tool returns 'HTTP status and content type for a public URL' and adds 'Body discarded,' which clearly sets expectations and distinguishes it from a full web-content fetcher. It is concise and specific enough for an agent to grasp the core function, though it could be slightly more direct with a verb like 'Fetch'.

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?

No guidance is given on when to use this tool versus siblings like 'fetch-status', 'browser-url-ok', or 'normalize-url'. The phrase 'for a public URL' implies a restriction to public URLs, but there is no explicit comparison or selection criteria, leaving the agent to infer the right context.

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