MCP

• Browse tests, modules, and environments
• Edit tests and modules via tool calls (not direct YAML edits)
• Create tests from natural language
• Run sessions with a live browser

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Prerequisites

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Step 1: Set up your MCP client

{
  "mcpServers": {
    "momentic": {
      "type": "stdio",
      "command": "npx",
      "args": ["momentic", "mcp", "--config", "/absolute/path/to/momentic.config.yaml"]
    }
  }
}

{
  "mcpServers": {
    "momentic": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "momentic",
        "mcp",
        "--config",
        "/absolute/path/to/momentic.config.yaml",
        "--headful-browser",
        "false",
        "--pixel-ratio",
        "2"
      ],
      "env": {
        "MOMENTIC_API_KEY": "your-api-key"
      }
    }
  }
}

{
  "mcpServers": {
    "momentic": {
      "type": "stdio",
      "command": "npx",
      "args": ["momentic", "mcp", "--config", "/absolute/path/to/momentic.config.yaml"]
    }
  }
}

{
  "mcpServers": {
    "momentic": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "momentic",
        "mcp",
        "--config",
        "/absolute/path/to/momentic.config.yaml",
        "--headful-browser",
        "false",
        "--pixel-ratio",
        "2"
      ],
      "env": {
        "MOMENTIC_API_KEY": "your-api-key"
      }
    }
  }
}

claude mcp add --transport stdio momentic -- npx momentic mcp --config /absolute/path/to/momentic.config.yaml

codex mcp add momentic -- npx momentic mcp --config /absolute/path/to/momentic.config.yaml

{
  "mcp": {
    "momentic": {
      "type": "local",
      "command": ["npx", "momentic", "mcp", "--config", "/absolute/path/to/momentic.config.yaml"],
      "enabled": true
    }
  }
}

{
  "mcp": {
    "momentic": {
      "type": "local",
      "command": [
        "npx",
        "momentic",
        "mcp",
        "--config",
        "/absolute/path/to/momentic.config.yaml",
        "--headful-browser",
        "false",
        "--pixel-ratio",
        "2"
      ],
      "enabled": true,
      "environment": {
        "MOMENTIC_API_KEY": "your-api-key"
      }
    }
  }
}

​

Step 2: Install the Momentic skill

npx momentic install-skills --cursor

npx momentic install-skills --claude-code

npx momentic install-skills --codex

npx momentic install-skills --opencode

npx momentic install-skills --copilot

npx momentic install-skills ~/my/custom/skills/momentic-test

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Step 3: Add an agent rule

Never directly edit Momentic test (`*.test.yaml`) or module YAMLs (`*.module.yaml`). Only use the Momentic MCP tools to edit Momentic YAMLs. If they are unavailable tell the user you are unable to edit the YAML files.

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Step 4: Verify installation

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Usage

1. Model selection: Choose the latest frontier models for the best performance. As of version 2.53.0, Momentic has benchmarked MCP performance on GPT5.3 Codex (High) and Opus 4.6 (High). If current agent performance is acceptable, Medium reasoning can improve speed by about 20%.
2. Invoke Momentic’s skill: Explicitly invoke the skill in your assistant (e.g. in Codex, type /momentic and choose the autocompleted skill).
3. Prompting: Specific instructions generally lead to better outcomes. For exploratory testing, we recommend specifying a step limit so that the agent knows when to stop.
4. Session management: Allow sessions to clean up properly. You should notice the model calling the momentic_session_terminate tool, which will close the browser instance. Repeatedly stopping your coding agent may leak browser resources and slow down your machine.

create a new test called demo test for the yc website

Then once you create that test load its full data, use this to then edit the test

click on the companies tab
choose a major name brand company and click on their profile
check that the team size is visible
click on the jobs tab
assert that the blurb about what the company does is no longer visible

name: "demo-test"
baseUrl: "https://www.ycombinator.com"
description: "Test for YC website - companies tab navigation and job page verification"

id: "391f065b-48f3-4548-ab15-079543fa69e0"

id: "391f065b-48f3-4548-ab15-079543fa69e0"
message: |
  Add test steps to:
  1. Navigate to the YC website
  2. Click on the 'Companies' tab
  3. Find and click on a major brand company like DoorDash or Coinbase
  4. Verify that the team size is visible on the company profile
  5. Click on the 'Jobs' tab
  6. Assert that the company description blurb is no longer visible on the jobs page

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Configurable settings

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Alternative protocol: Streamable HTTP

POST/GET/DELETE /api/mcp/
Header: mcp-session-id: <session-id>
url: http://localhost:58888/api/mcp

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IDE configuration

{
  "mcpServers": {
    "momentic": {
      "url": "http://localhost:58888/api/mcp"
    }
  }
}

{
  "mcpServers": {
    "momentic": {
      "serverUrl": "http://localhost:58888/api/mcp"
    }
  }
}