navigate

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

With no annotations, the description carries the full burden and does reasonably well: it discloses the browser-only behavior of raising the browser window, that denied URL patterns are refused by policy, and that a RESULT line plus fresh observation comes back. It omits failure/timeout handling and any permission requirements, but the policy and focus behavior are genuinely useful context beyond the 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?

Three short sentences, front-loaded with the core action and result, then the two behavioral caveats. Every sentence carries information and nothing is repeated from the schema.

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?

An output schema exists, so the return values need no explanation, and the one parameter is fully covered by the schema. The description correctly fills the remaining gaps (policy refusal, window focus), though it could say what happens if navigation fails or times out.

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% and the single url parameter is fully documented in the schema, including absolute-URL format and file:// examples. The description adds no syntax, encoding, or constraint detail beyond that, so 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?

States a specific verb and resource ('Open a URL in the agent's own browser tab') plus the side effect ('return the page tree once it has loaded'). This distinguishes it from siblings like observe (no navigation) and click (no page load), so an agent can route correctly without opening the schema.

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 the use case (opening a URL) and adds a policy caveat about denied patterns, but never states when to prefer navigate over siblings such as observe or click, nor any precondition like needing a launched browser. Usage is inferable rather than stated.

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