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

The description discloses one behavioral aspect: no browser is launched. This is useful for understanding side effects but omits other potential behaviors like network requests, timeout handling, or criteria for 'can be opened'. Given the absence of annotations, more transparency would be beneficial.

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 extremely concise, consisting of two short sentences. It avoids unnecessary wording and gets to the point quickly. No redundancy or filler content.

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 description covers the basic function but lacks critical context. It does not specify what 'can be opened' means (e.g., HTTP status, connectivity), what the output format is (no output schema), or how the numerous parameters affect the check. For a simple tool, it may be minimally adequate, but given the parameter confusion, more explanation is needed.

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?

While the schema descriptions cover 100% of parameters (each has a short description), many parameters (ref, city, feed, json, path, zone, query) seem unrelated to the tool's stated purpose of checking URL accessibility. The descriptions are generic and do not explain how these parameters relate to the URL check, causing confusion. The tool's focus is unclear from the parameter set.

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 clearly states the tool's action ('Check whether a URL can be opened') and resource (URL). However, it does not distinguish this tool from sibling tools like 'playwright-url-ok' or 'fetch-status', which likely serve similar purposes. The added note 'No browser is launched' hints at a lightweight nature but does not explicitly differentiate.

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 provides a single usage hint ('No browser is launched'), implying a non-interactive check. However, it lacks explicit guidance on when to prefer this tool over alternatives, such as 'fetch-status' or 'web-fetch'. No conditions or example scenarios are given.

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