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

With no annotations, the description carries full behavioral burden. It discloses only that no browser is launched, but does not explain what checking actually involves: network request, timeout, response status, side effects, or return behavior. This is thin for a tool with 9 parameters and no output schema.

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, front-loaded with the core purpose and the key behavioral caveat. Every word earns its place; there is no fluff or repetition.

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 is too sparse for a 9-parameter tool with no annotations and no output schema. It fails to clarify what 'can be opened' means, what happens with the various optional inputs, what the tool returns, or how it relates to sibling URL/network tools.

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 schema already documents each parameter. The description adds no parameter-level meaning, which is acceptable under the baseline rule, but it also does not clarify how the many non-URL parameters relate to the stated 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?

States a specific action and resource: checking whether a URL can be opened. The phrase 'No browser is launched' adds useful distinction from browser-based checks, though it does not explicitly name or differentiate the sibling tool browser-url-ok.

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 use for URL openability checks without launching a browser, but it gives no explicit when-to-use or when-not-to-use guidance and does not mention alternatives such as browser-url-ok or fetch-status.

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