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

Annotations are absent, so the description must disclose behavior on its own. It reveals only that no browser is launched, but does not say whether it makes a network request, returns a status, or performs a syntax check, nor any side effects or limits (auth, rate). This leaves the agent guessing about the actual mechanism and return contract.

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-load the purpose and add a meaningful caveat. No redundant words; every sentence contributes.

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 no or output schema and no annotations, this two-sentence description is underspecified. It doesn't define what a positive/negative result means, doesn't explain the role of the seven parameters (several labeled 'discarded'), and doesn't map the behavior to any concrete signal. An agent could not confidently interpret the result or know which input to supply.

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 descriptions cover 100% of the 7 parameters, so the baseline is 3. The description does not mention any parameter or clarify which of the many inputs is relevant to a 'URL' check, but the schema already carries the parameter detail.

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 uses a 明确的 verb ('Check') and names the resource (a URL), and the second sentence distinguishes it from browser-based checks by noting no browser is launched. However, 'can be opened' is ambiguous—it could mean HTTP reachability, valid syntax, or renderability—so it does not fully discriminate from siblings like normalize-url or fetch-status.

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 sentence states when to use this tool or when to prefer an alternative. The 'No browser' caveat implies it is lighter-weight than browser-url-ok, but there is no explicit routing or excluded cases, and siblings like fetch-status and normalize-url are not referenced.

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