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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only reveals that no browser is launched, which is helpful, but it fails to describe the actual network behavior (e.g., whether an HTTP request is made), the output format, error handling, or side effects. This is insufficient for an agent to predict the tool's full 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?

The description is extremely concise, consisting of two short sentences with no extraneous information. It front-loads the primary action and includes a key behavioral note about browser usage. Every word earns its place.

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?

Given the tool's moderate complexity (9 optional parameters, no output schema, no annotations), the description is notably incomplete. It does not explain what 'can be opened' means in practice, the expected result, failure modes, or which parameters are actually used. The description leaves significant gaps that an agent would need to resolve through trial or additional context.

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?

The schema descriptions cover all 9 parameters (100% coverage), so the baseline is 3. The tool description itself adds no additional meaning about how parameters relate to the URL check; it does not clarify which parameters are relevant or how they affect the outcome. The schema descriptions are informative but do not tie back to the tool's purpose, leaving some ambiguity (e.g., why city, feed, and zone are accepted).

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 clearly states the tool's purpose: to check whether a URL can be opened, with a specific verb and resource. It also explicitly differentiates itself from likely sibling tools (e.g., browser-url-ok) by noting 'No browser is launched.' This is concise and unambiguous.

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 provides no guidance on when to use this tool versus alternatives. It does not mention any sibling tools or conditions that would favor this tool over others like fetch-status or normalize-url. There is no explicit context or exclusion, leaving the agent to infer when this tool is appropriate.

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