macos-vision-mcp

_{Your documents and your screen stay on the machine. Only extracted text and structured JSON ever reach the model.}

Local, private, offline OCR and UI testing for any MCP client — no API keys, no uploads. Cut document token costs by ~97%, and let an agent see and click your Mac's UI without a single screenshot leaving the machine.

Pre-extracts text and image data locally before your AI ever sees it — cutting token usage by ~97% on real documents and returning structured paragraphs, lines, and bounding boxes so the model can reconstruct the document into Markdown, HTML, DOCX, or any other format. Files never leave your Mac: no cloud API, no API keys, no network requests.

_{How the ~97% is measured: a 44-page scanned PDF sent as page images costs ~73,500 tokens; the same file run through analyze_document returns ~2,400 tokens of extracted text and structure (raw page-image tokens vs. extracted-text tokens). Your numbers vary with page density and tokenizer — treat 97% as the order of magnitude, not a guarantee.}

Contents: Quick Start · What you get · What agents use this for · UI testing · Why it's different · Available Tools · Usage · Example workflows · Configuration · Privacy layer

What you get

• OCR for images and PDFs (JPG, PNG, HEIC, TIFF, multi-page PDF) via Apple Vision Framework.
• ~97% token reduction: a 44-page PDF costs ~2,400 tokens instead of ~73,500.
• Reading-order paragraphs + raw text blocks with bounding boxes — rich structure for the model to reconstruct the document into any output format (Markdown, HTML, DOCX, JSON), not a lossy plain-text dump.
• Face detection, barcode/QR reading, and image classification — all on-device.
• Full document pipeline: OCR + faces + barcodes + rectangles in a single tool call.
• Works with Claude Code, Claude Desktop, and Cursor — any MCP-compatible client.
• No files uploaded to any server — processing stays entirely on your Mac.
• UI testing for agents: screenshot a window locally, find an element by its visible text, get back click coordinates, and assert what's on screen — all without uploading the screenshot.
• 100% offline after npm install — powered by Apple Vision Framework, same engine as Live Text in Photos.app.

❌ Without / ✅ With

❌ Without macos-vision-mcp:

• Sending a 44-page PDF costs ~73,500 tokens
• Every image, invoice, or contract goes through a cloud API
• Sensitive documents leave your machine on every request

✅ With macos-vision-mcp:

• Local Apple Vision pre-extracts text before Claude ever sees it
• ~2,400 tokens for the same 44-page PDF — 97% fewer
• Files never leave your Mac

What agents use this for

Most work an agent does on a Mac needs no deep understanding of a layout. It needs to see what is on screen, find the thing it is looking for, act on it, and confirm what happened. That loop — list_windows → find_element → click (via any input driver) → assert_text — covers a lot, and every step of it runs on the machine.

• Drive an app that has no API. Native tools, Electron apps, internal software, anything with a GUI and no scripting interface. find_element("Export") returns the point to click.
• Read what is on screen right now. A dialog, an error banner, a notification, a progress state — including a window sitting behind others, without bringing it to the front.
• Confirm an action actually worked. assert_text is string matching after unicode normalisation, so it answers pass/fail the same way every time instead of asking a model to judge a picture.
• Pull data out of software that will not export it. OCR a window, get the text, move on.
• Audit accessibility. ui_snapshot reports every piece of visible text the accessibility tree does not account for — unlabelled controls and custom-drawn text, with coordinates.
• Test a UI for regressions. The case this started as, and still a good one — see the chapter below.
• Work through documents. The original job: invoices, contracts, scans, PDFs.

Why doing it locally is better, not just different

Cheaper. A verdict costs ~240 tokens against ~6,900 for the screenshot it replaces — about 29×. Over a twenty-step task that is ~4,800 tokens instead of ~138,000. It is the difference between an agent that can afford to check its work after every step and one that cannot.

More private, and this is the part that never shows up on a bill. A screenshot is not a neat crop of the button you cared about. It carries whatever else was on screen: another window, a password manager, an open inbox, a customer's record. Sending one to a third party is a disclosure you cannot withdraw, and it repeats on every single step. Here the image is written to a temp file, read by a model on the Neural Engine, and never serialised into the conversation. That invariant is enforced in the code, not promised in this README: no tool returns image bytes.

Faster in practice, and predictable, which matters more. find_element takes 1.17–1.25 s end to end on an M1 Pro — capture 0.31–0.41 s, OCR ~1.04 s, matching under a millisecond. There is no network term at all: no ~750 KB upload before inference can start, no rate limit, no provider under load, no failure when the Wi-Fi drops. The same call costs the same on a plane as it does at a desk.

What this does not do: click. It is eyes, not hands, and therefore never asks for control of your machine. Pair it with an input driver — cliclick, a macos-mcp-style automation server, or anything that accepts screen coordinates — and hand it the clickPoint that find_element returns. The split is deliberate: seeing and acting are different permissions, and this server only ever asks for the first.

UI testing without sending screenshots anywhere

The usual way to let an agent work with a GUI is to screenshot the screen and upload it to a vision model. That is one network round trip, one image-token bill, and one copy of whatever was on screen — per step. A ten-step flow means ten uploads of your desktop.

This server does the seeing locally. Apple's Vision framework runs on the Neural Engine, so the screenshot stays on disk and only text, geometry, and verdicts reach the model.

_{What the agent actually receives. Element boxes, roles and labels — measured, not guessed — and the exact point to click. The screenshot itself never leaves the Mac.}

find_element(query: "Save", app: "MyApp")
  → { found: true, matches: [{ text: "Save", method: "exact",
        clickPoint: { x: 812, y: 556 }, bbox: {...} }] }

# hand clickPoint to any input driver — macos-mcp, cliclick, CGEvent
# then verify, again locally:

assert_text(expect: "Saved", app: "MyApp")  → { pass: true, ... }

clickPoint is in global screen points with a top-left origin — the same space click drivers use, so it goes straight to a driver with no conversion. This server deliberately does not click: it is eyes, not hands, and therefore never asks for control of your machine.

Is it actually cheaper, safer, and faster?

Measured on an Apple M1 Pro (2021, 16 GB) against a 2992×1734 Retina window capture of a real, text-dense app — median of five runs each.

_{Image tokens are estimated with Anthropic's width × height / 750 rule; other providers tile differently, so the exact figure moves but the order of magnitude does not. Local token counts are the actual JSON payloads the tools returned, at ~4 characters per token.}

_{Same question, same answer, ~29× the price. Measured on an M1 Pro against a 2992×1734 window capture.}

The three claims behind that table — cheaper, safer, faster — are argued in What agents use this for above. What this section adds is the measurement: the numbers are a median of five runs on an Apple M1 Pro (2021, 16 GB) against a 2992×1734 Retina capture of a real, text-dense window.

We have not benchmarked any specific vision provider, so treat the right-hand column as structure rather than a measured figure. What can be stated is that the local path has no variance from bandwidth, rate limits or provider load, and does not fail when the network does.

Two honest caveats. Targeting a single region instead of a whole window cuts the OCR term sharply, since cost scales with pixels searched. And the first call after install spends ~2 s compiling a small Swift helper; every call after that is warm.

What it is good at — and what it is not

Good at: native macOS apps, Electron apps with poor accessibility, canvas/WebGL UIs, games, and design mockups — anything where there is no DOM to query. Also good when you want a deterministic assertion rather than a model's opinion: assert_text is string matching after unicode normalisation, so it returns the same answer every time.

Not the right tool for a plain web page: Playwright or the DOM will be faster and more precise there. And OCR only sees what is rendered, so it cannot read a control's enabled state or its accessibility role.

Text matching is normalised before comparison — NFC, collapsed whitespace, unicode dashes and quotes folded — then tried exact → substring → fuzzy (Levenshtein). When a match is rejected it is still reported under nearMisses, so "the label is there but OCR read Zapisr for Zapisz" is distinguishable from "the label is genuinely absent".

Substring hits are graded rather than treated alike: a query that stands on word boundaries, opens the label, and covers more of it scores higher. That ordering matters when the answer is a button — for the query Save, Save Changes must outrank Don't Save. Each match reports wholeWord, and assert_text decides its verdict only on matches where it is true: Save inside Unsaved changes is a coincidence of spelling, and it neither proves a Save button is on screen nor proves it is gone. Such hits are still listed, under incidental.

Requirements

• Screen Recording permission for the app hosting the MCP server (Terminal, Claude Desktop, Cursor): System Settings → Privacy & Security → Screen Recording, then restart that app. No compiler or Xcode tooling is needed — the native helper arrives prebuilt.

  The grant is per host process, not per package: the same server can be fully working under one client and blind under another on the same Mac. Without it, capture fails outright and macOS additionally withholds every window title, so list_windows reports title: "" for everything — that case is flagged as titlesAvailable: false rather than left to look like a screen full of untitled windows. Run vision_capabilities first: ready and blockers say what works right now.

• An unlocked Mac. On a locked machine window and region capture fail outright and a full-screen capture returns only the lock screen; vision_capabilities reports screenLocked so an agent can check before it starts rather than guessing at a failure afterwards.

Why it's different

Most OCR options for LLMs either ship your documents to a cloud vision API or make you stand up and tune your own engine. This runs on Apple's on-device Vision framework — the same engine behind Live Text in Photos.app — so extraction is free, private, and instant.

The trade-off is honest: it's macOS-only, and on heavily skewed or low-contrast scans a cloud model may still read more. For the common case — invoices, contracts, receipts, screenshots, clean PDFs — you get cloud-grade extraction with zero cost, zero setup, and nothing leaving your machine.

Privacy layer

macos-vision-mcp acts as a local pre-processing layer between your documents and the cloud. Useful for:

• Legal documents, contracts, NDAs
• Financial reports, invoices, internal spreadsheets
• Medical records or any GDPR-sensitive content
• Any situation where you want to extract structured data locally before deciding what (if anything) to send upstream

Instead of sending the raw document to your AI, you extract the text and structure locally first. The model then works only with the extracted text — never the original file.

The same applies to your screen. A screenshot taken for one small check still carries everything else that happened to be visible — other windows, a password manager, a customer record, an open inbox. The UI-testing tools keep that image on disk and return only paths, geometry, and text, so a UI assertion does not become an unplanned disclosure. No tool in this server returns image bytes to the model.

Quick Start

Add to your MCP client (example for Claude Code):

claude mcp add macos-vision-mcp -- npx -y macos-vision-mcp

Using Claude Desktop or Cursor? Jump to Configuration ↓

Restart your client. npx fetches the package on first run, caches it, and the tools appear automatically — no separate install step. This is the convention used by most MCP servers and recommended by Anthropic, Cursor, and other clients.

Note: On first run, the package downloads prebuilt Swift helper binaries (vision-helper, pdf-helper, ui-helper, ax-helper) from its GitHub Releases (~276 KB compressed, ~1–2s). Subsequent invocations hit the npx cache and start instantly. Xcode Command Line Tools are only required as a fallback when the download can't reach the network — set MACOS_VISION_SKIP_DOWNLOAD=1 to force local compilation with swiftc.

Prefer instant cold-starts (no npx cache lookup)? Install globally with npm install -g macos-vision-mcp and use the alternative config shown at the bottom of Configuration.

Available Tools

UI-testing tools (local, no screenshots sent to the cloud)

These tools let an agent see and verify your Mac's UI without ever sending a screenshot to a cloud model. Screenshots are captured locally, OCR runs on-device, and only paths, geometry, and extracted text are returned. find_element gives click coordinates in screen points, ready to hand to any input driver (this server deliberately does not click — eyes, not hands).

Requires Screen Recording permission for the app hosting the MCP server (Terminal / Claude Desktop / Cursor): System Settings → Privacy & Security → Screen Recording, then restart that app. Nothing else to install — the native helper ships prebuilt with macos-vision.

ui_snapshot — the layout, not just the text

find_element answers "where is X". ui_snapshot answers "what is on this screen": every element's measured box (from the accessibility API, not inferred from OCR), its role, label and enabled state, the parent/child structure, and optionally colours sampled from the capture and real font data.

{
  "app": "MyApp",
  "window": [0, 29, 1496, 867],
  "source": "ax+px",
  "budget": { "elements": 289, "walked": 400, "capped": false, "elapsedMs": 136 },
  "nodes": [
    {
      "id": 42,
      "parent": 7,
      "role": "Button",
      "label": "Zapisz",
      "box": [812, 540, 96, 32],
      "style": { "bg": "#2F6FEB", "border": "#1B4FC4", "borderWidth": 1 },
      "text": { "font": "SFPro-Semibold", "size": 13, "align": "center" },
    },
  ],
  "unresolved": [{ "text": "Sprzedaż Q4", "box": [420, 300, 88, 16], "coveredByNode": 17 }],
  "summary": {
    "nodes": 289,
    "labelled": 240,
    "ocrBlocks": 123,
    "unresolved": 21,
    "axTextCoverage": 0.83,
  },
}

unresolved is text Vision can read that no accessibility node accounts for. It completes the picture where AX is blind — canvas, WebGL, games, text baked into images — and each entry is an accessibility gap in the app: coveredByNode present means a control is there but unlabelled, absent means nothing is exposed at all.

Read it honestly: budget.capped means the tree is incomplete, and summary.axTextCoverage is null in that case on purpose — a capped walk measures how much was visited, not how accessible the app is. Colours come from pixels, so an occluded element reports whatever is drawn on top; borderWidth is inferred and there is no padding or margin. This is not the CSS box model.

Needs Accessibility permission in addition to Screen Recording, and an unlocked Mac — a locked screen exposes no accessibility windows at all.

Usage

Use the tool name explicitly in your prompt to guarantee local processing:

Extract text from an image or PDF:

Use ocr_image to extract text from ~/Desktop/invoice.pdf

Detect faces in a photo:

Use detect_faces on ~/Photos/team.jpg and tell me how many people are in it

Classify image content:

Use classify_image on ~/Downloads/unknown.jpg

Full document analysis + reconstruction:

Use analyze_document on ~/Desktop/report.pdf and reconstruct it as clean Markdown

The tool returns structured JSON; the model picks the output format you ask for (Markdown, HTML, DOCX outline, etc.) without any extra dependencies — no Ollama, no cloud LLM, no extra tooling.

Example workflows

Real-world combinations that work out of the box once the server is connected:

• "Convert PDF → clean Markdown for LLM" — analyze_document returns reading-order paragraphs and bounding boxes; the model renders Markdown ready to drop into a docs site, knowledge base, or RAG pipeline.
• "Extract invoice data locally before sending to GPT" — pull line items, totals, vendor, and dates from the PDF locally with analyze_document, then send only the structured JSON upstream. The original document never leaves your Mac.
• "Scan receipts → JSON → expense tracker" — ocr_image on a phone photo, the model normalizes amount / date / merchant, and pipes the result straight into your expense tool's API.
• "Decode a QR code from a screenshot" — detect_barcodes returns the decoded value plus symbology in one round trip.
• "Crop a photo of a paper form before OCR" — detect_document returns the four corner points so you (or a downstream tool) can deskew and crop the image before reading the text.
• "Click the Save button in my app" — find_element returns clickPoint in screen points; hand it to a click driver (macos-mcp, cliclick). The screenshot never leaves the Mac.
• "Check my app still renders correctly after this change" — assert_text gives a deterministic pass/fail on what is on screen, at ~240 tokens per check instead of ~6,900 for the screenshot.
• "Read the error message in that background window" — read_screen_text captures a specific window, even one hidden behind others, and returns just the text.
• "What is my app showing right now?" — list_windows to pick the target, read_screen_text to read it, without bringing the window to the front.

Output schema (analyze_document)

{
  "source": { "path": "...", "pageCount": 1, "isPdf": false },
  "pages": [
    {
      "page": 0,
      // primary surface for reconstruction — reading-order paragraphs joined with "\n"
      "paragraphs": [
        { "paragraphId": 0, "lineIds": [0], "text": "ACME COFFEE" },
        { "paragraphId": 1, "lineIds": [1, 2], "text": "12 Main St\nPortland, OR" },
      ],
      // spatial fallback — raw blocks with page-local 0–1 bbox, confidence, line/paragraph membership
      "textBlocks": [
        {
          "text": "ACME COFFEE",
          "lineId": 0,
          "paragraphId": 0,
          "confidence": 0.99,
          "bbox": { "x": 0.21, "y": 0.04, "width": 0.58, "height": 0.06 },
        },
      ],
      "faces": [],
      "barcodes": [],
      "rectangles": [],
    },
  ],
  "summary": {
    "totalTextBlocks": 8,
    "totalParagraphs": 2,
    "totalFaces": 0,
    "totalBarcodes": 0,
    "totalRectangles": 0,
  },
}

Use paragraphs[].text for the 95% case (rebuild Markdown/HTML/plain text directly). Reach for textBlocks[] when you need spatial context — multi-column layouts, tables, forms, IDs.

Notes:

• ocr_image in blocks mode returns the same per-page shape minus the detection sections: { pages: [{ page, paragraphs, textBlocks }] }.
• PDFs are processed page by page. All coordinates are page-local (0–1), and paragraphId / lineId reset on every page.
• Face, barcode, and rectangle detection on PDFs is best-effort — the underlying binary analyzes the file as a whole rather than per page, so any detections returned are attached to page 0 only.
• Paragraph grouping uses spatial heuristics. For multi-column layouts (magazine spreads, wiki pages with side panels) the heuristic can collapse the whole page into a single paragraph. When that happens, fall back to textBlocks[] and reconstruct from the bounding boxes.

Configuration

All examples below use npx -y — the recommended default. No prior npm install needed; the package is fetched and cached on first run, and updates pick up automatically when the npx cache rolls over.

Claude Code

claude mcp add macos-vision-mcp -- npx -y macos-vision-mcp

Claude Desktop

Edit ~/Library/Application Support/Claude/claude_desktop_config.json:

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

Cursor

Add to ~/.cursor/mcp.json:

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

Alternative: global install

If you'd rather skip the npx cache lookup on cold starts — or you want to pin a specific version — install once:

npm install -g macos-vision-mcp

…then use "command": "macos-vision-mcp" (no args) in any of the JSON configs above, or claude mcp add macos-vision-mcp -- macos-vision-mcp for Claude Code. Note that global installs can break when switching Node versions with nvm / asdf / volta — re-run npm install -g after switching.

Support

If macos-vision-mcp saved you tokens or kept a document on your Mac, consider starring the repo — it helps others find it.

Contributing

Contributions are welcome. Please follow Conventional Commits for commit messages.

Releases run on changesets. If your change is user-visible, add a changeset to the PR:

npm run changeset   # pick patch / minor / major, describe the change

Merging to master then opens a "version packages" PR that bumps the version, server.json and the changelog; merging that PR publishes to npm (Trusted Publishing, with provenance), tags the release, and refreshes the MCP registry entry.

git clone <repo>
cd macos-vision-mcp
npm install
npm run dev   # watch mode

License

MIT — Adrian Wolczuk