@corralimited/snapdiff-mcp

@corralimited/snapdiff-mcp

Standalone MCP server for SnapDiff. Exposes four tools to local agents:

• Compare two web pages visually — diff percentage plus a highlighted diff image
• Capture a screenshot of any URL
• Check whether a page changed vs. a previous capture
• Render HTML/CSS to an image (OG cards, social images, email headers)

Hits the public SnapDiff REST API. Bring your own API key.

Quickstart

Get an API key at https://snapdiff.ai/dashboard, then drop the snippet for your agent below.

Claude Code

claude mcp add snapdiff -e SNAPDIFF_API_KEY=sk_live_... -- npx -y @corralimited/snapdiff-mcp

Or edit ~/.claude/settings.json:

{
  "mcpServers": {
    "snapdiff": {
      "command": "npx",
      "args": ["-y", "@corralimited/snapdiff-mcp"],
      "env": { "SNAPDIFF_API_KEY": "sk_live_..." }
    }
  }
}

Cursor

~/.cursor/mcp.json (or project-level .cursor/mcp.json):

{
  "mcpServers": {
    "snapdiff": {
      "command": "npx",
      "args": ["-y", "@corralimited/snapdiff-mcp"],
      "env": { "SNAPDIFF_API_KEY": "sk_live_..." }
    }
  }
}

Cline (VS Code)

Cline > MCP Servers > Edit Config:

{
  "mcpServers": {
    "snapdiff": {
      "command": "npx",
      "args": ["-y", "@corralimited/snapdiff-mcp"],
      "env": { "SNAPDIFF_API_KEY": "sk_live_..." }
    }
  }
}

Zed

~/.config/zed/settings.json:

{
  "context_servers": {
    "snapdiff": {
      "command": {
        "path": "npx",
        "args": ["-y", "@corralimited/snapdiff-mcp"],
        "env": { "SNAPDIFF_API_KEY": "sk_live_..." }
      }
    }
  }
}

Continue

~/.continue/config.yaml:

mcpServers:
  - name: snapdiff
    command: npx
    args: ["-y", "@corralimited/snapdiff-mcp"]
    env:
      SNAPDIFF_API_KEY: sk_live_...

Anything else with a generic stdio MCP slot

command: npx
args:    -y @corralimited/snapdiff-mcp
env:     SNAPDIFF_API_KEY=sk_live_...

Tools

Name	Purpose
snapdiff_verify_ui_change	Checks whether a visual change matches the agent's stated intent. Returns verdict (pass / expected_change_detected / unexpected_regression / no_change_detected / needs_human_review) and a next_action. Requires a project + baseline. Use this in the verification loop.
snapdiff_compare_pages	Raw visual diff between two URLs, or a URL vs. a stored project baseline. Use for ad-hoc diffs that don't fit the verify-ui-change verdict shape.
snapdiff_capture_screenshot	Single screenshot of a URL.
snapdiff_html_to_image	Render HTML/CSS to an image (OG cards, social images, email headers).

Schemas live in src/tools/ and are exported from @corralimited/snapdiff-mcp/tools. The hosted SnapDiff backend imports the same schemas so its in-process /mcp endpoint and this standalone stdio server expose an identical surface — agents see the same tool names, descriptions, and parameters whether they connect to https://api.snapdiff.ai/mcp or run this server locally.

Remote HTTP access

This package speaks stdio only — your editor spawns it as a subprocess, and the Playwright-backed localhost tools run on your machine, where your dev server actually is. It does not open a port.

If you need an HTTP endpoint, use the hosted one at https://mcp.snapdiff.ai/mcp, which authenticates every request with your API key and exposes the same tool surface.

Configuration

Env var	Required	Notes
SNAPDIFF_API_KEY	yes	Get one at https://snapdiff.ai/dashboard
SNAPDIFF_API_URL	no	Override the API base. Defaults to https://api.snapdiff.ai/v1.

There are no CLI flags beyond --help.

License

MIT — see LICENSE.