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

With no annotations, the description bears the full disclosure burden, yet it only reveals that no browser is launched. It does not state whether the tool makes a network request, what side effects (if any) occur, whether authentication is needed, or what the result means beyond 'can be opened'.

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-loaded with the core action and followed by a key qualifier. No filler or repetition.

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 nine optional parameters, no annotations, and no output schema, the description is too sparse. It does not clarify which parameter should be supplied, what the expected return value looks like, or how 'can be opened' is determined, leaving an agent to guess.

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 baseline is 3. The description itself adds no parameter-level meaning, but each parameter already has a description in the schema; the odd mix of unrelated parameters (city, query, ref) is not explained, which prevents a higher score.

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 names a specific action ('Check whether a URL can be opened') and resource (URL), and the sentence 'No browser is launched' separates it from browser-based siblings like browser-url-ok. However, it does not specify how the check is performed (HTTP status, DNS, renderability), so it stops short of a fully precise definition.

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 for quick reachability checks when browser rendering is not required, but it never names alternatives such as browser-url-ok or fetch-status, nor gives explicit when-to-use/when-not-to-use conditions.

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