url

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

The readOnlyHint annotation already communicates that this is a read-only operation. The description adds no further behavioral details, such as side effects or navigation behavior, but it does not contradict the annotation.

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 a single, concise sentence with no extraneous words. It is front-loaded and immediately clear.

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 simple read-only tool with fully documented optional parameters and no output schema, the description is sufficient. It lacks an explicit return-type statement but the intended result is obvious from the name and description.

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 input schema covers both parameters with detailed descriptions, so the description does not need to add parameter semantics. The description itself does not mention the optional 'lease' and 'session' parameters, but schema coverage is complete.

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 'Get current URL' uses a clear verb and resource, directly stating the tool's function. It distinguishes itself from sibling tools like 'title' and 'text' by explicitly naming the URL as the target.

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 when the current page URL is needed, but it does not explicitly contrast with alternatives such as 'title' or 'html'. There is no stated when-to-use or when-not-to-use guidance beyond the simple purpose.

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