real-browser-mcp

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browser_webmcp_list_tools

Lists WebMCP tools the current page registers for AI agents and reports supported:false when the browser or page lacks WebMCP support.

Instructions

List WebMCP tools the current page registers for agents (document.modelContext.getTools()). Returns supported:false when the browser or page has no WebMCP support.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "browser_webmcp_list_tools"
  }
}

Input Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

Addedv1.4.0Oct 26, 2026

TDQS

A3.9/5.0

Behavior3/5

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

With no annotations, the description carries the full burden, and it adds useful return behavior by noting supported:false when WebMCP is unavailable. However, it does not state that the operation is read-only, whether it has side effects, or how registered tools are represented.

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 tightly written sentences with no filler. The primary purpose is front-loaded and the unsupported-case fallback follows immediately.

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?

For a zero-parameter discovery tool with no annotations and no output schema, the description is adequate but incomplete: it explains the fallback, yet does not describe the shape of the tool list returned when WebMCP is supported. An agent would know what it does but not fully what to expect back.

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?

The tool has zero parameters, so there are no parameter semantics to explain; the baseline is 4. The description correctly does not invent parameter details.

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 uses a specific verb+resource ('List WebMCP tools') and scopes it precisely to tools the current page registers for agents, even naming the underlying API. It naturally distinguishes discovery from the sibling browser_webmcp_execute_tool.

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 current-page/agent context implies when the tool is useful, but there is no explicit guidance such as using it before browser_webmcp_execute_tool or when not to use it. Usage is implied rather than stated.

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