oh-my-mcp

Overview Schema Source Related Servers Discussions Admin

browser_open

Opens a new browser instance to navigate to a URL. Returns a unique session ID for further operations. Options for headless mode, window size, user agent, and proxy.

Instructions

Open a new browser session and navigate to a URL.

Creates a new browser instance (Chrome or Edge) and navigates to the specified URL. Returns a unique session ID for subsequent operations.

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": {
      "url": "<url>"
    },
    "name": "browser_open"
  }
}

Input Schema

Name	Required	Description	Default
`url`	Yes	URL to navigate to after opening the browser
`browser`	No	Browser type to use ("chrome" or "edge")	chrome
`headless`	No	Run in headless mode without visible window
`window_size`	No	Initial window size in WxH format (e.g., "1920x1080")	1920x1080
`user_agent`	No	Custom user agent string (optional)
`proxy`	No	Proxy server URL (optional)

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0May 25, 2026

TDQS

A3.6/5.0

Behavior2/5

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

With no annotations, the description carries full burden. It mentions creating a new browser instance and returning a session ID, but fails to disclose potential resource usage, the need to close sessions, or implications of headless mode.

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 short sentences that convey the essential purpose and return value without unnecessary words. Front-loaded with the core action.

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 tool with 6 parameters and an output schema, the description covers the key behavior and return. It could mention error handling or session management, but it's largely adequate.

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 baseline is 3. The description adds minimal parameter detail beyond what the schema already provides, only reiterating the creation and navigation aspects.

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 clearly states the tool opens a new browser session and navigates to a URL. It distinguishes from sibling tools like browser_navigate (which reuses an existing session) by emphasizing the creation of a new instance.

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 explains the tool's function and return value but does not provide explicit guidance on when to use it versus alternatives (e.g., browser_navigate for existing sessions) or when not to use it.

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

Deploy Server