Drawing Converter MCP Server

Convert technical drawings (PDF) and engineering callouts between metric and imperial — from any MCP-enabled AI assistant.

This Model Context Protocol server exposes the conversion engine behind metric-to-imperial-converter.imnoo.com (by Imnoo): shop-floor-precision unit conversion for dimensions, ± tolerances, ISO fit classes, threads, surface roughness and weights — including producing a converted copy of a drawing PDF with every value stamped in place.

"Convert bracket.pdf to imperial and tell me what replaces the M8 thread"

        │

        ▼  (your AI assistant calls the tools)

extract_drawing_text ──► classify values ──► convert_drawing_pdf

                                                   │

                                                   ▼

                                    bracket.imperial.pdf  ✓ Ø30 H7 → Ø1.1811 H7

                                                          ✓ M8     → 5/16-18 UNC

Tools

Plus a convert-drawing prompt that walks the assistant through extract → classify → convert.

The AI-analysis step stays with your assistant. extract_drawing_text hands the model every printed token with its position; the model decides which tokens are real values (and whether a bare 3.2 is a length or an Ra roughness) and passes that as classifications to convert_drawing_pdf. No API keys, no cloud calls — the server itself is fully deterministic and offline.

Installation

Requires Node.js ≥ 18.

Claude Code

claude mcp add drawing-converter -- npx -y drawing-converter-mcp

Claude Desktop

Add to claude_desktop_config.json (Settings → Developer → Edit Config):

{

  "mcpServers": {

    "drawing-converter": {

      "command": "npx",

      "args": ["-y", "drawing-converter-mcp"]

    }

  }

}

Cursor

Add to Cursor — or add to ~/.cursor/mcp.json:

{

  "mcpServers": {

    "drawing-converter": {

      "command": "npx",

      "args": ["-y", "drawing-converter-mcp"]

    }

  }

}

VS Code (GitHub Copilot)

code --add-mcp '{"name":"drawing-converter","command":"npx","args":["-y","drawing-converter-mcp"]}'

Windsurf / other stdio clients

Any client that launches stdio servers works with:

npx -y drawing-converter-mcp

Example session

You: Convert C:\drawings\flange.pdf to imperial.

Assistant: calls extract_drawing_text — 63 tokens, source system: metric (high confidence — "mm", ISO 2768). classifies tokens, skips the title block, marks 1.6 next to the surface symbol as roughness, calls convert_drawing_pdf — wrote C:\drawings\flange.imperial.pdf, 17 values converted: Ø40 H7 → Ø1.5748 H7, 2× M6 → 1/4-20 UNC (nearest standard — not interchangeable), Ra 1.6 → Ra 63 µin…

Quick one-liners work too: "what's 84±0.1 mm in inches?" → convert_text → 3.3071±0.0039.

Precision rules

Conversions follow the same rules as the web app:

• Exact factors by international definition (25.4 mm/in, 0.45359237 kg/lb — NIST/ISO 80000).
• Display rounding mirrors shop-floor convention: a 0.01 mm step maps to 4-decimal inches; tolerance deviations keep an extra significant digit.
• Threads are resolved against an ISO-metric ⇄ UNC chart (M2–M30), tagged table for charted rows or nearest when snapped by major diameter. Metric and inch threads are never interchangeable — the tools say so on every thread conversion.
• Every converted value reports how it was derived (exact / rounded / table / nearest) and a confidence score.

Limitations

• The PDF must have a text layer. Scanned or flattened CAD exports have none — the web app handles those with in-browser OCR + AI analysis.
• One page is converted per call (page parameter, default 1); other pages pass through unchanged.
• Fractional-inch callouts (1 3/4) aren't converted yet — decimal-inch drawings work fine.
• Converted values are stamped over the original callouts. Always verify safety-critical dimensions before manufacturing use.

Development

This package is built from the Drawing Converter monorepo at Imnoo, where it imports the web app's conversion engine directly — so the web app and this server convert identically by construction. Every release is gated on 31 end-to-end checks that drive all five tools over stdio against a generated sample drawing.

Issues and feature requests are welcome in this repository.

About Imnoo

Imnoo — The System for Manufacturers | AI Planning, Scheduling & Quoting · Complete Assemblies · DFM · Tool & Material Libraries · Quoted-Parts Database · Toolpath & G-Code · Machine Connection · Webshop · ERP · Shop Analytics & Optimization · Drawing Masking & IP Security

Plan It. Schedule It. Quote It. Win It. — trusted by over 3,000 manufacturers.

Imnoo is the AI-powered planning, scheduling, and quoting platform for CNC manufacturers — your automatic production platform. One system that covers it all: automatic manufacturing planning with raw-material, catalog and purchase-part, and subcontracting sourcing; scheduling with smart reminders and AI-driven customer workflows; and AI cost and cycle-time estimation for milling, turning, and EDM — even from a 2D PDF alone. Quote complete assemblies: drop in one file and Imnoo explodes it into single parts automatically — with DFM checks, quality protocols, tolerance extraction and 2D-to-3D matching, toolpath and G-code generation, tool and machine recommendations, and connected machines feeding real production data back into every quote. Built on your own tool and material libraries and a growing database of every part you've ever quoted — powering statistics, benchmarks, and shop optimization. Extends to deep hole drilling, sheet metal, casting, and profile parts — with a 24/7 webshop, built-in ERP, hourly-rate calculation, market-price benchmarking, and imperial ⇄ metric conversion. Your data lives in its own physically separated environment — automatic drawing masking, Swiss hosting, end-to-end encryption. From messy RFQ to production-ready order, on one platform.

Planning

• Automatic manufacturing planning — production plans generated straight from the quote.
• Machine recommendation — every job routed to the machine that runs it best.
• Catalog & purchase part management — norm parts, screws, and bought-in components recognized straight from the BOM, managed and priced alongside your machined parts.
• Raw material sourcing — price, source, and order material without leaving the workflow.
• Purchase part & external step sourcing — bought-in components, coating, heat treatment, and subcontracting sourced and ordered in the same flow.
• Beyond milling & turning — deep hole drilling, sheet metal, casting, and profile parts.

Scheduling & Workflow

• Scheduling & smart reminders — via email, Telegram, or WhatsApp. Nothing slips.
• Email-to-quote automation — a messy inbox in, structured quotes out.
• AI customer agents — RFQ answers, clarifications, and follow-ups handled automatically.
• Built-in lightweight ERP — orders, companies, payment terms, and margins without the bulky software.

Quoting & Estimation

• Complete assemblies, exploded automatically — upload one assembly file and Imnoo blows it out into single parts: every component recognized, drawings matched to the right parts, sub-assemblies nested, purchase parts pulled from the BOM. Quote the whole machine as easily as one part.
• CNC quoting in one place — milling, turning, and EDM jobs quoted from a single AI-powered platform.
• AI cost & cycle-time estimation — know price, time, and effort before engineering ever looks at it.
• Drawing-only estimation — quote from the PDF alone. No 3D model needed.
• Feature-by-feature costing — see exactly which holes, pockets, and tolerances drive the price.
• Instant quotes — respond in minutes while competitors are still opening the STEP file.
• 24/7 instant-quoting webshop — customers upload parts and buy while you sleep.
• Instant market-price benchmarking — know where your bid stands before you send it.