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

The description discloses one behavioral trait—no browser launch—but with no annotations, it carries the full burden of behavioral disclosure. It does not mention whether a network request is made, whether the check is synchronous, what response is returned, or what side effects (e.g., caching, logging) may occur.

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 two short sentences with no filler. The core purpose is front-loaded, and the clarifying note about no browser launch is immediately useful and concise.

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 9-parameter tool with no output schema and no annotations, this description is incomplete. It does not explain which parameter is relevant to the check, how the other parameters behave, or what the tool returns. An agent would be uncertain about the tool's full behavior and result format.

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 all 9 parameters already have individual descriptions. The tool description itself adds no parameter-level meaning, but because the schema covers all parameters, the baseline score of 3 is appropriate.

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 clarifying constraint, 'No browser is launched.' This gives the basic purpose, but 'can be opened' is somewhat ambiguous (network reachability vs. URL format), and it does not explicitly distinguish the tool from siblings like browser-url-ok or fetch-status.

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 guidance on when to use this tool versus alternatives such as browser-url-ok, fetch-status, or web-fetch. 'No browser is launched' hints at a contrast with browser-based checks, but no explicit when-to-use or when-not-to-use guidance is provided.

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