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

With no annotations, the description carries the full burden of behavioral disclosure. It discloses one useful trait (no browser), but does not say whether the tool makes a network request, follows redirects, has side effects on the target, or what 'can be opened' means without a browser.

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 first states the primary function and the second adds a critical behavioral qualification. The most important distinguishing information is front-loaded.

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 seven parameters, no annotations, and no output schema, this one-line description is not enough. It omits which parameters are relevant, how they interact, the expected return shape, and the network/safety implications of the check.

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?

The schema provides per-parameter descriptions, giving a high baseline, but the tool description fails to tie them together and actually conflicts with the schema's 'url' description (normalize or cite vs. can be opened). Unrelated parameters like city, json, feed, and path are never explained in light of the stated URL-opening purpose.

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 operation—check whether a URL can be opened—and immediately distinguishes itself from browser-based siblings by declaring that no browser is launched. This is enough for an agent to tell browser-url-ok apart from playwright-url-ok 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 'No browser is launched' sentence implies it is the lightweight alternative to a real-browser check, but it never names an alternative or gives an explicit when-to-use/when-not-to-use rule. The guidance is implied rather than stated.

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