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

The only behavioral note is 'No browser is launched,' which hints at a non-destructive check but does not explain side effects, return values, or what 'can be opened' means in practice. With no annotations provided, this sparse disclosure is insufficient.

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 a single brief sentence, which is concise but lacks structure. It does not break down the tool's behavior, inputs, or outputs, making it too terse to be useful.

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 9 parameters and no output schema, the description is grossly incomplete. It fails to explain what the tool returns, how the parameters affect the result, or what 'ok' means. An agent cannot infer correct usage from this alone.

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?

Although schema coverage is 100%, the parameter descriptions are inconsistent with the tool's stated purpose. Terms like 'discarded after the shape check' and 'public weather hint' suggest a broader validation tool, but the description does not unify them. The descriptions add little clarity about how each parameter contributes to the 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 'Check whether a URL can be opened' but immediately clarifies 'No browser is launched,' which is contradictory. The actual function appears to be a generic shape checker for multiple input types, as evidenced by unrelated parameters like city, timezone, and query. The description does not clearly convey what the tool actually does.

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 siblings such as fetch-status, normalize-url, or playwright-url-ok. The description does not mention any conditions or alternatives, leaving the agent to guess the appropriate context.

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