---
title: "List custom WebMCP tools"
method: GET
path: "/browsers/{id_or_name}/webmcp/custom-tools"
tags: ["Browser WebMCP"]
---

# List custom WebMCP tools

`GET /browsers/{id_or_name}/webmcp/custom-tools`

## Request

- Base URL: `https://api.onkernel.com`
- URL: `https://api.onkernel.com/browsers/{id_or_name}/webmcp/custom-tools`
- Auth: HTTP bearer

Returns every registered custom tool with its generated ID, namespace, matcher, and MCP tool metadata.

## Response `200`

Current custom WebMCP tools

- CustomWebMCPToolsResponse
  - `tools` CustomWebMCPDefinition[], required
    - `id` string, required
    - `kind` string, required
    - `match` CustomWebMCPMatch, required
      - `url_patterns` string[], required
    - `namespace` string, required
    - `tool` WebMCPToolMetadata, required: Tool metadata follows the [MCP Tool definition](https://modelcontextprotocol.io/specification/2025-11-25/server/tools#tool) and the [WebMCP RegisteredTool definition](https://webmachinelearning.github.io/webmcp/#dictdef-registeredtool). outputSchema is optional for page and custom tools.
      - `annotations` WebMCPToolAnnotations: Tool-provided behavioral hints from the [MCP tool specification](https://modelcontextprotocol.io/specification/2025-11-25/server/tools#tool) and the [WebMCP ToolAnnotations definition](https://webmachinelearning.github.io/webmcp/#dictdef-toolannotations). These hints are untrusted and are not enforced by Kernel.
        - `autosubmit` boolean
        - `consequentialHint` boolean
        - `destructiveHint` boolean
        - `idempotentHint` boolean
        - `openWorldHint` boolean
        - `readOnlyHint` boolean
        - `untrustedContentHint` boolean
      - `description` string, required
      - `inputSchema` object, required
      - `name` string, required
      - `outputSchema` object
      - `title` string

## Other responses

- `500`: Internal Server Error
- `default`: Error returned by the browser or its proxy

## Changes

- **2026-09-25** `743e00322e20`: 1 info
  - endpoint added

[Operation history](https://skmtc.dev/onkernel/apis/kernel-api/changes/browsers/:id_or_name/webmcp/custom-tools/get.md)

---

[API](https://skmtc.dev/onkernel/apis/kernel-api.md) - [All operations](https://skmtc.dev/onkernel/apis/kernel-api/llms.txt) - [OpenAPI document](https://skmtc.dev/onkernel/apis/kernel-api/revisions/0f6cf4f58fe6?raw)