OpenTakeoff

Measure construction plans in your browser, or hand the same engine to your AI agent.

Free, open source and local. Nothing uploads, and nobody has to sign up.

▶ Try it now · 🔌 Plug in your agent · 🛠 Send your first PR

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A takeoff is the measuring that every construction bid starts with: how much floor, how much wall, how many fixtures, at what scale and on which sheet. OpenTakeoff is an open-source engine for that job. It has two front ends:

• 🧑🔧 A browser canvas for people. Drag in a plan set, set the scale, trace rooms, and export a report and a marked-up planset.
• 🤖 An MCP server for agents. It offers 62 tools over stdio. An agent drives the same engine with the same math and the same scale gate as the canvas, and its work stays a dashed proposal until a person accepts it.

Both front ends share one takeoff format, so you can open an agent's takeoff in the canvas, check it and fix it. Every shape records the scale it was measured at, the method that drew it, and whether a person or an agent drew it.

[!NOTE]

One-Click Area is temporarily gated while the flood engine is re-validated on a wider

plan corpus. Trace rooms with Area (A) in the canvas and measure_polygon over MCP.

Every other tool works as normal. See docs/design/ONE_CLICK_GATE.md.

Pick your door

Plug it into your agent

The server needs Node 20 or newer. You don't need to clone or build anything. Pick your client:

{

"mcpServers": { "opentakeoff": { "command": "npx", "args": ["-y", "opentakeoff-mcp"] } } }

If you've cloned the repo, the root .mcp.json, .cursor/mcp.json and .vscode/mcp.json register the server when you open the folder, so there's nothing else to set up.

Your first prompt. Paste this once the server is connected:

Load demo/sample-finish-plan.pdf from the OpenTakeoff repo, read the scale note on the floor

plan, set the scale, trace room 134 on its wall faces under its finish tag from the

schedule, check your ring with view_sheet, and export the marked-up PDF.

The step-by-step walkthrough for each client is in Connect OpenTakeoff to your AI. The server can also describe itself: read the takeoff://wiki resource before you load a plan.

All 62 tools, grouped by stage

The generated reference, with the required arguments for each tool, is docs/MCP_TOOL_INDEX.md. The full tool reference is mcp/README.md.

How a takeoff runs

*A real run at 3× speed. The agent takes off patient rooms 161–163 on a federal finish plan and exports after each commit. Each shape lands in the canvas as a dashed proposal and becomes ink only when the operator clicks Accept.* Watch it live and uncut: autonomous agent run (2:47) · finish plan to report in about a minute (1:14) · canvas walkthrough (1:10)

The rules that make it safe to hand to a model

1. Scale is a gate, not a default. The engine reads the scale note but never applies it on its own. Measuring an unscaled sheet is refused.
2. The ring sits on the wall faces. Rooms are traced on the innermost wall-face strokes. Doors are crossed on the wall centerline, and the agent checks each ring on a rendered overlay before it moves on.
3. Agent work stays pencil until a person inks it. An agent can sign its own work with an AGENT diamond. Only a person at the canvas can apply the green APPROVED seal.
4. Withheld is an answer. When a sweep or a derivation can't be sure, it says why and hands back coordinates. It doesn't return a plausible number.
5. The deliverable is a marked-up planset, not JSON. export_marked_pdf burns the work into the drawings behind a legend cover with totals.

The full contract, with the reasoning behind each rule, is in the tour.

What's new

October 2026

• ✨ The scan star. OpenTakeoff has a new mark for its AI. The star ripples while the agent works and shows up in the Work panel, the Agent tab and the watermark on exported PDFs (#571, #576).
• 💲 Estimate and proposal. You can now price a takeoff by hand (unit, material and labor, tax, overhead and profit), export it to Excel and download a letter-size bid proposal PDF. Agents get the same features through five new verbs: set_pricing, set_estimate_settings, estimate_summary, export_estimate and export_proposal. Prices always come from the estimator, and nothing fills one in for you (#558–#562, MCP 0.9.99).
• 🪟 Reference split-screen. You can now keep a read-only second sheet open beside the one you're tracing (#570, by @knmurphy).
• 🗂 Sheets as a tree. Multi-page PDFs show up as folders, and each row is labeled with the sheet number from its title block (#523).
• ⚡ A faster room engine. Exact grid indexes replace quadratic scans. On a 24-sheet replay, all 548 room probes came back identical, and buildNet time dropped by 2.4× to 2.5× on the slowest sheets (#540, #547, #550).
• 🔐 Security refresh. The MCP SDK and Zod 4 were upgraded without changing the tool set or the takeoff payloads (#566, MCP 0.9.100).

September 2026: on-device OCR for scanned sheets, plan-set text search, Copy text, schedule import from raster pages, the annotation toolbar, Pin references and a guided first takeoff. Everything is in the CHANGELOG, and the older highlights are in the tour.

What's in the box

| Conditions | A color and CAD hatch for each finish, waste