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

Annotations are absent, so the description must carry the behavioral burden. It adds two useful details: 'public URL' (scope constraint) and 'Body discarded' (side-effect note). However, it does not disclose error behavior, redirects, rate limits, or what happens for non-public URLs. Given no annotations, a 3 is appropriate – it provides some value but is not rich.

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 a single sentence with zero waste. It is front-loaded with the core action and result. Perfectly concise for the information it conveys.

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 and no output schema. The description only addresses the URL behavior, ignoring all other parameters (ref, city, feed, host, json, path, zone, query). It fails to explain the overall purpose of these parameters or how they are used, making the definition incomplete for an agent to call correctly. A description this sparse is inadequate for a multi-parameter tool.

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 the schema itself provides per-parameter explanations (e.g., 'discarded after the shape check'). The tool description does not add any meaning beyond the schema – it does not explain how parameters relate to the main URL operation or how to prioritize them. Baseline 3 is correct.

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 a specific verb and resource: 'HTTP status and content type for a public URL.' It clearly indicates what the tool does (fetches a URL and reports status/content type) and explicitly notes the body is discarded. However, it does not name alternatives or differentiate from sibling tools like fetch-status or browser-url-ok, so it loses one point.

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?

There is no guidance on when to use this tool versus alternatives. It does not mention any conditions, exclusions, or prerequisites. The description only states what it does, not when to choose it over siblings. This is a clear gap.

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