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

With no annotations, the description must disclose behavior, but it only says no browser is launched. It does not state that this performs a network request, whether it is read-only, what 'opened' means, or what the tool returns. Key behavioral expectations are left to inference.

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, front-loaded sentences make the main point immediately. The prose is efficient, though it omits necessary context that would reduce ambiguity.

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 parameters, no annotations, and no output schema, but the description is only one sentence about URLs. It does not explain the role of city, feed, json, host, or query params, nor what the tool returns. An agent cannot confidently select and invoke the correct option from this description alone.

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 parameters are individually documented. The description adds no parameter guidance and does not explain which of the nine parameters is primary or how they interact with the URL check.

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 ('Check') and resource ('whether a URL can be opened'), and the note 'No browser is launched' differentiates it from browser-url-ok. It is slightly vague about what 'opened' means, but the core action is 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 'No browser is launched' clause implies this is the lightweight alternative to a browser-based check, but the description does not explicitly name alternatives or state when to use this tool over fetch-status or normalize-url. No exclusions are provided.

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