web-ui-tester

Navigate

browser_navigate

Navigate a browser session to a URL and receive an updated page snapshot with element references for UI testing.

Instructions

Navigates the session to a URL and returns the new page state plus a fresh snapshot with element refs. Relative URLs resolve against the session baseUrl.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "sessionId": "<sessionId>",
      "url": "<url>"
    },
    "name": "browser_navigate"
  }
}

Input Schema

Name	Required	Description
`url`	Yes	Absolute URL, or a path relative to the session baseUrl.
`sessionId`	Yes	Session id returned by browser_start.
`waitUntil`	No	Navigation completion condition. Defaults to "load".

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Aug 24, 2026

TDQS

A3.6/5.0

Behavior3/5

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

With annotations readOnlyHint=false and openWorldHint=true, the bar is lowered. The description adds that it returns a snapshot and that relative URLs resolve against baseUrl, which is useful. However, it does not disclose other behavioral traits such as side effects on the session or blocking behavior, but annotations already cover the mutation aspect.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two concise sentences with the main action front-loaded. No wasteful words; the relative URL detail is relevant and efficiently placed.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a navigation tool, the description is adequate: it specifies the result (page state + snapshot) and URL handling. It does not mention error conditions or prerequisites (e.g., session must be active), but these are implied by the schema and sibling context. Given annotations and schema richness, this is fairly complete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the schema documents all parameters. The description only repeats the relative URL behavior already stated in the schema ('Absolute URL, or a path relative to the session baseUrl'). It adds no new meaning beyond what the schema provides, so a baseline of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb ('Navigates') and resource ('session to a URL'), and mentions it returns page state and a fresh snapshot. It is clear and distinct from siblings (e.g., go_back, start) but does not explicitly name the alternatives.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies when to use this tool (for navigation) and clarifies relative URL resolution, but it does not explicitly contrast with sibling tools like browser_go_back or browser_start. Context is clear but no exclusions or when-not-to-use guidance is given.

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