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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only states 'No browser is launched,' which is a negative constraint. It does not disclose what happens with the many parameters (many are discarded), whether there are side effects, permissions, or what the return value looks like. This is a significant gap for a tool with 9 parameters.

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 very concise, just one sentence, and front-loaded with the core action. However, it is so brief that it lacks any structured detail about the tool's breadth of inputs or behavior. It is efficient but under-specified for the tool's complexity.

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 9 parameters and no output schema, yet the description only explains a single capability (checking URL openability) without explaining how the diverse parameters (city, json, path, etc.) relate to that purpose. An agent cannot fully understand the tool's scope or when to invoke it from this description alone.

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 each parameter is described in the schema (e.g., 'Git ref name; discarded after the shape check'). The tool description itself adds no information about parameters, but since the schema already documents them thoroughly, the baseline of 3 applies.

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 action: 'Check whether a URL can be opened' and adds a key behavioral note 'No browser is launched.' This distinguishes it from browser-url-ok, which likely does launch a browser. It is clear on the primary purpose, though it doesn't mention the wide variety of input parameters.

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 no guidance on when to use this tool versus alternatives like normalize-url, web-fetch, or browser-url-ok. It does not state conditions, exclusions, or mention any sibling tools. An agent has to infer usage from the name and schema.

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