scan-mcp

Minimal MCP server for scanner capture (ADF/duplex/page-size), batching, and multipage assembly.

• Small, typed MCP server exposing tools for device discovery and scan jobs
• JSON Schema–validated inputs with deterministic, typed outputs
• Smart device selection (prefers ADF/duplex, avoids camera backends), robust defaults

Note: This package targets Node 22 and Linux SANE backends (scanimage).

Quick Start (MCP client config)

Add a server entry to your MCP client configuration:

{
  "mcpServers": {
    "scan": {
      "command": "npx",
      "args": [
        "-y",
        "scan-mcp"
      ],
      "env": {
        "INBOX_DIR": "~/Documents/scanned_documents/inbox"
      }
    }
  }
}

• Call start_scan_job without a device_id to auto-select a scanner and begin scanning.
• Artifacts are written under INBOX_DIR per job: job-*/page_*.tiff, doc_*.tiff, manifest.json, events.jsonl.

Install

• Run with npx: npx scan-mcp
  • The CLI runs a quick preflight check for Node 22+ and required scanner/image tools and prints installation hints if anything is missing.
• CLI help: scan-mcp --help
• Install npm: npm i -g scan-mcp then scan-mcp
• From source (development):
  • npm install
  • npm run build
  • MCP clients can run via node dist/mcp.js or npx tsx src/mcp.ts

System Requirements

• Linux with SANE utilities: scanimage (and optionally scanadf)
• TIFF tools: tiffcp (preferred) or ImageMagick convert

Environment Variables

• SCAN_MOCK (default: false): mock SANE calls and generate fake TIFFs for testing.
• INBOX_DIR (default: scanned_documents/inbox): base directory for job runs and artifacts.
• SCANIMAGE_BIN / SCANADF_BIN (defaults: scanimage / scanadf): override binary paths.
• TIFFCP_BIN / IM_CONVERT_BIN (defaults: tiffcp / convert): multipage assembly tools.
• SCAN_EXCLUDE_BACKENDS (CSV): backends to exclude (e.g., v4l).
• SCAN_PREFER_BACKENDS (CSV): preferred backends (e.g., epjitsu,epson2).
• PERSIST_LAST_USED_DEVICE (default: true): persist and lightly prefer last used device.

Tools

• list_devices: Discover connected scanners with backend details.
• get_device_options: Probe options for a given device_id.
• start_scan_job: Start a job (auto-selects device if omitted). Creates per-page TIFFs, assembles documents.
• get_job_status: Inspect job state and artifact paths.
• cancel_job: Request job cancellation (best-effort during scan loops).

See JSON Schemas in schemas/ for shapes of inputs/outputs. Tests assert against these contracts.

How Selection and Defaults Work

Defaults aim for 300dpi, reasonable color mode, and ADF/duplex when available. Full details on scoring and fallbacks live in docs:

• Selection and defaults: docs/SELECTION.md

Project Layout

• src/mcp.ts — MCP server entry and tool registration
• src/services/* — hardware interface and job orchestration
• schemas/ — JSON Schemas used for validation and tests
• docs/ — architecture, conventions, and deep dives

Development

• npm run dev (stdio MCP server), npm run dev:http (experimental HTTP)
• make verify runs lint, typecheck, and tests
• Conventions: docs/CONVENTIONS.md and architecture in docs/BLUEPRINT.md

Roadmap

Tracking ideas and future improvements are documented in docs/ROADMAP.md.

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