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.

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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_...

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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.

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HTTP transport (advanced)

Besides stdio, if you're hosting an MCP gateway and need a streamable HTTP server, run with --http:

SNAPDIFF_API_KEY=sk_live_... npx @corralimited/snapdiff-mcp --http --port 8787

Then point clients at http://localhost:8787/mcp with the standard MCP HTTP transport.

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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. |

CLI flags (HTTP mode only):

| Flag | Default | Notes | | ------------ | ----------- | ------------------------------------------------- | | --http | off | Run as a streamable HTTP server instead of stdio. | | --port <n> | 8787 | Port for --http mode. | | --host <h> | 127.0.0.1 | Bind address for --http mode. |

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License

MIT — see LICENSE.