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

With no annotations, the description carries the transparency burden. It discloses one important behavior—no browser is launched—but does not explain what 'open' means, whether a network request is made, what side effects may occur, or what result is returned.

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, each earning its place: the core operation and the key behavioral caveat. There is no redundancy or filler.

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 parameters, many siblings, and no output schema, this is under-specified. It does not describe the return value, how openability is determined, or how this tool relates to the similarly named sibling tools, so an agent may struggle to interpret the result or choose the right tool.

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 nine parameters are already documented in the schema. The description adds no additional parameter-level meaning, matching the baseline for full schema coverage.

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 verb and resource: 'Check whether a URL can be opened,' and adds a meaningful method qualifier, 'No browser is launched.' It does not explicitly differentiate from sibling tools such as browser-url-ok, but the no-browser caveat hints at the distinction.

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 only usage signal is 'No browser is launched,' which implies this is for lightweight URL openability checks when browser automation is not needed. It does not name alternatives or state when not to use it, leaving the guidance implicit.

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