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

With no annotations, the description carries the full burden. It does disclose a meaningful behavioral trait—no browser is launched—and 'check' implies a read-only operation. However, it does not clarify whether the tool makes a network request or merely validates URL shape, and 'can be opened' remains ambiguous.

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 with no wasted words. The core purpose is front-loaded and the key behavioral caveat follows immediately. Every part earns its place.

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?

The tool has nine optional parameters, no output schema, and no annotations, yet the description does not explain what the tool returns, how 'opened' is determined, or that only `url` should be used. An agent has too little context to invoke it confidently.

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 even though the free-text description adds nothing about parameters. The schema's `url` description, 'HTTPS URL to normalize or cite,' does not fully match the tool's stated purpose, and most other parameters appear irrelevant or discarded. The property name `url` helps, but the description does not disambiguate which parameter actually matters.

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?

States a specific verb and resource: check whether a URL can be opened. The second sentence, 'No browser is launched,' differentiates it from browser-based siblings like playwright-url-ok, so an agent can tell what this tool does without opening the schema.

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 description implies a lightweight/headless URL check through 'No browser is launched,' but it never explicitly states when to use this tool versus alternatives such as playwright-url-ok, fetch-status, or web-fetch. Usage guidance is only implied, not stated.

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