open_url

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

No annotations are provided, so the description carries the burden. It discloses the core behavior (opening a URL) and the tab behavior (active vs new tab), but doesn't mention side effects like navigation, potential page load delays, or whether the tool waits for page load. For a simple action, this is adequate but not rich.

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 that front-loads the action and target. No wasted words; it earns its place.

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 two-parameter tool with no output schema, the description covers the essential action and tab behavior. However, it doesn't mention error cases (e.g., invalid URL, unsupported scheme) or whether the tool returns any status. Given the simplicity, it's mostly complete but could add a note on validation.

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 0%, so the description must compensate. It mentions the URL and the newTab option implicitly ('active tab or a new tab'), but doesn't explain the url format beyond 'http(s)' or the default behavior of newTab. The schema already defines the parameters, so the description adds minimal extra meaning.

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 verb ('Open') and resource ('an http(s) URL') and clarifies the target ('active tab or a new tab'). It is clear and distinguishes from siblings like read_page or click, though it doesn't explicitly name alternatives.

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 when to use it (opening URLs) but provides no explicit guidance on when not to use it or alternatives. For example, it doesn't mention that read_page is for reading content or that type_text is for input. The context is clear but exclusions are absent.

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