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Navigate current browser session

browser_navigate

Navigate to a URL in an existing browser session, reusing the active tab or creating a default session. Returns page details and handles timeouts, network, and parse failures.

Instructions

Loads url into an existing browser session, replacing its current document and adding a history entry. Use this instead of browser_open when continuing in a known session; if session_id is omitted, the active session is reused or a default session is created. It waits up to timeout seconds and returns the resulting URL, title, viewport, scroll position, and indexed elements; network, timeout, size, and parse failures return an error object without changing committed page state.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
urlYesTarget URL to navigate to.
timeoutNoTimeout in seconds for page load (maximum 30 seconds).
session_idNoOptional browser tab/session identifier.

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault

No arguments

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed1 schema field changedv1.3.5
    • changedOutput schema / (root)
      Previous value: -nullNew value: +{
+  "additionalProperties": true,
+  "type": "object"
+}
  2. First observedv1.3.2

TDQS

A4.9/5.0
Behavior5/5

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

Annotations only mark safety traits; the description adds substantive behavior: active-session reuse or default session creation, the exact data returned, and the guarantee that failures return an error without changing committed page state. This is beyond what annotations provide and does not contradict them.

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 sentences front-load the core navigation action, then add usage routing and failure behavior without redundancy. Every clause earns its place.

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

Completeness5/5

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

For a 3-parameter tool with an output schema, the description covers invocation context, behavior, return contents, and error semantics. Nothing an agent needs to call it correctly is missing.

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

Parameters4/5

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

Schema coverage is 100%, so the schema carries the parameter basics. The description adds value for session_id by defining what happens when it is omitted, and it confirms url and timeout semantics in context. This justifies moving above the baseline 3.

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

Purpose5/5

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

The description opens with a specific verb and resource ('Loads `url` into an existing browser session') and explains the document-replacing, history-adding effect. It also names the sibling alternative (browser_open), so an agent can distinguish navigation from opening a session.

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

Usage Guidelines5/5

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

It explicitly states when to choose this over browser_open ('continuing in a known session') and explains fallback behavior when session_id is omitted. It also covers timeout and failure conditions, giving clear context for invocation.

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

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