usable-browser-agent-free

browser_os_click

Click at specified screen coordinates using a real OS mouse event. Use for trusted clicks or native chrome automation on macOS.

Instructions

Click at absolute screen coordinates with a REAL OS mouse event. Prefer browser_click; use this only for trusted clicks or native chrome. macOS only; raw clicks need brew install cliclick.

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": {
      "x": "<x>",
      "y": "<y>"
    },
    "name": "browser_os_click"
  }
}

Input Schema

Name	Required	Description
`x`	Yes
`y`	Yes
`count`	No	2 = double-click.
`button`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.7.0Sep 9, 2026

TDQS

A4.1/5.0

Behavior3/5

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

No annotations are provided, so the description carries the full burden. It discloses key traits: real OS event vs synthetic, macOS-only, and cliclick dependency. However, it omits operational details like macOS Accessibility permissions, focus requirements, or error behavior when cliclick is missing.

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?

Three compact sentences with zero waste: core purpose front-loaded, then usage guidance and dependency. Every sentence earns its place.

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

Completeness3/5

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

Covers purpose, when-to-use, platform, and dependency. However, with no output schema and no annotations, it fails to disclose the return value or failure modes (e.g., what happens if cliclick isn't installed or if the OS blocks the event).

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 only 25% (only count has a description; x and y are bare). The description adds meaning to x/y via 'absolute screen coordinates', clarifying the coordinate system. But it doesn't specify coordinate origin, units, or range, and button is only self-documenting via its enum.

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?

States a specific verb (click), resource (absolute screen coordinates), and method (REAL OS mouse event). Clearly differentiates from browser_click by emphasizing the 'REAL OS mouse event' and 'absolute' coordinate system, which sets it apart from its sibling tools.

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?

Explicitly instructs to prefer browser_click and use this only for trusted clicks or native chrome. Also states the platform constraint (macOS only) and the prerequisite (brew install cliclick), leaving no ambiguity about when to select this tool.

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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