browser_navigate

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

Adds rich behavioral context beyond annotations: allowlist enforcement and refusal message ('origin not allowed'), timeout behavior (~6s with 'no preview pane running'), credential page gating, and replacement of current page. Annotations declare idempotentHint and non-destructive, but the description provides operational failure modes and preconditions that are essential for correct invocation.

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 sentences, front-loaded with the core action, followed by constraints and failure modes. No wasted words, but the sentence about credential access is somewhat abrupt and could be integrated more elegantly.

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?

Given a single-parameter tool with no output schema, the description covers purpose, environment prerequisites, allowlist constraints, failure modes, and special cases (credential pages). An agent has all necessary information to attempt the call and interpret errors. Output schema absence is mitigated by stating what is returned ('Answers the URL loaded').

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 schema description already explains absolute vs. relative URL formats with examples. The description adds no additional parameter semantics beyond what the schema provides, so baseline 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?

Specific verb+resource: 'Load a URL in the preview, replacing the current page.' Clearly distinguishes from sibling inspection tools like browser_console or browser_dom. An agent can identify this as the navigation tool immediately.

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?

Describes the preconditions—'Needs Reado's browser preview open with agent access on'—and the allowlist conditions. It explains when the call fails but doesn't explicitly suggest alternatives for when navigation is refused. Clear context, no explicit exclusions.

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