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

No annotations are provided, so the description bears the full burden of behavioral disclosure. It reveals one useful trait (no browser is launched), but it does not state whether a network request happens, whether the operation is read-only, what the return value looks like, or that most inputs are discarded.

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 two sentences are short and front-loaded, but this is under-specification rather than concise completeness for a nine-parameter tool. The description omits the tool's multi-input nature and its output, so the brevity does not serve the agent's decision-making.

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?

With no annotations, no output schema, and nine heterogeneous parameters, the description must explain overall behavior, return semantics, and parameter selection, but it only addresses URL checking. The description is inadequate for an agent to call this tool correctly for non-URL inputs.

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 each parameter has a meaningful description and the baseline is 3. The tool description itself adds no parameter-level detail, and its narrow focus on URL actually obscures the other eight accepted input types, but it does not misdescribe any specific parameter.

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 action ('Check whether a URL can be opened') and adds a useful behavioral note ('No browser is launched'), but the purpose is ambiguous because the input schema accepts nine unrelated params such as city, json, path, zone, and query, which the description does not acknowledge. It also does not clarify what 'opened' means, leaving uncertainty about whether this is a syntax check, a network reachability check, or something else.

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 explicit guidance on when to use this tool versus siblings like browser-url-ok, normalize-url, or fetch-status. The only hint, 'No browser is launched', is a behavioral note rather than a usage rule, so an agent cannot confidently decide between this and similar tools.

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