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

The description discloses one important behavior: 'No browser is launched,' which clarifies that this is a lightweight check. However, with no annotations provided, the description carries the full burden, and it does not disclose what 'ok' means (HTTP status? URL parseability? robots.txt?), whether network access occurs, what side effects exist, or what the return value is. The parameter descriptions add some behavioral hints (e.g., 'no disk access', 'discarded after the check'), but the main description remains thin.

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 short and front-loaded: the core purpose and the key behavioral caveat appear in the first sentence. It earns its place with no filler. However, the brevity comes at the cost of missing usage and behavioral context, so it is not a 5.

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 10 parameters, no annotations, no output schema, and a large sibling list, the description is incomplete. An agent cannot tell what inputs are appropriate, what the tool returns, how it differs from playwright-url-ok or fetch-status, or what 'ok' means. The parameter descriptions hint at validation/discard behavior, but the overall tool contract is underspecified.

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 schema already documents all 10 parameters. The description itself adds no parameter-level meaning beyond the schema, and the parameter list is confusingly heterogeneous (URL, city, JSON, timezone, search text, file path). The baseline of 3 applies because the schema does the heavy lifting, but the description does not help an agent understand why these parameters belong together or which are relevant for a 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 clear verb and resource ('Check whether a URL can be opened') and adds a useful behavioral note ('No browser is launched'). However, the tool name 'browser-url-ok' and the 10 heterogeneous parameters (ref, city, feed, host, json, path, zone, query, website) make the actual scope ambiguous: it is not clearly distinguished from siblings like fetch-status, normalize-url, web-fetch, or playwright-url-ok, and the description does not explain why unrelated parameters exist.

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 guidance is given about when to use this tool versus alternatives such as playwright-url-ok, fetch-status, or normalize-url. The description only says what it does, not when it should be selected, and the parameter list suggests many unrelated use cases without any conditional guidance.

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