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

No annotations exist, so the description carries the full behavioral burden. It discloses one meaningful behavior — that no browser is launched — but fails to explain what the check actually performs (network request vs. static validation), what it returns, or side effects. For an annotation-less tool this is thin but not misleading.

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 zero waste. The primary action and the critical behavioral caveat are front-loaded. This is an appropriately concise definition.

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 9 parameters, no annotations, and no output schema, the description is under-specified. It doesn't explain how the diverse parameters relate to the check, what the tool returns, or the exact semantics of 'can be opened.' An agent calling this correctly would need substantially more information.

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 coverage is 100%, so the baseline is 3. The description adds no parameter detail beyond the schema. Notably, several params (city, zone, json, path, query) appear unrelated to a URL-openability check, and the description doesn't reconcile this mismatch, though the schema descriptions themselves carry the load.

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 clear verb-resource pair ('Check whether a URL can be opened') and adds a key disambiguator against the sibling playwright-url-ok with 'No browser is launched.' It doesn't fully define what 'opened' means (HTTP reachability? format validity?), but the core purpose is understandable and differentiates from the most similar sibling.

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 phrase 'No browser is launched' implicitly signals when NOT to use this tool (when a real browser render is needed, use playwright-url-ok instead). However, it never names alternatives or clarifies when to prefer this over fetch-status, web-fetch, or normalize-url. Guidance is implied, not explicit.

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