Cold Open 0.1.0-alpha.3

The third alpha of Cold Open: a free, open-source screenwriting app that reads and writes Fountain and .fdx files, paginates the same on every computer, and journals every keystroke, so a crash costs nothing.

This is an alpha. Keep copies of anything that matters. Your scripts are plain Fountain and .fdx files, so nothing you write here is locked in.

New here? The website has everything: downloads, the user guide, and the tester guide, a 20-minute tour.

What's new since alpha.2

• One download for every Mac. The universal disk image runs on Apple chips and Intel alike, and fits the 15 MB budget. The per-chip images are still there, a little smaller.
• Settings (Ctrl+Comma, or Cmd+Comma on a Mac, where it's also Cold Open ▸ Settings…): the theme, interface size, renderer, your name on tracked changes, agent access, crash reports and the usage summary, in one sheet you can use from the keyboard alone.
• Share feedback… (palette, About, start screen): type what you think and open our form or a GitHub issue with it filled in. Nothing is sent until you submit it yourself.
• A usage summary, on your computer only. Cold Open counts which features you use, so feedback can say what you rely on. It holds counts, never your text, names or file paths, and Cold Open never sends it: it goes out only if you tick Include my usage summary when you share feedback, and you see all of it first. Settings shows it in full, resets it, or turns counting off. See what it holds.
• Saving an .fdx file on a Mac no longer holds the app up for a few milliseconds. After each save Cold Open flushed the drive once more than it needed to, and the next save could wait for it.
• The new icon, in the project's final brand.
• For AI clients: ColdOpen-0.1.0-alpha.3-mcp.mcpb holds Cold Open's MCP server for clients that install MCP bundles.
• The full list is in the changelog.

Which file to download

The download page recommends the right one for your computer. By hand:

Your computer	File
Windows 10 or 11 (most PCs)	ColdOpen-0.1.0-alpha.3-windows-x64-setup.exe
Windows on ARM (Surface Pro X, Snapdragon laptops)	ColdOpen-0.1.0-alpha.3-windows-arm64-setup.exe
Windows, without installing	the .zip for your processor
Any Mac with macOS 12 or later	ColdOpen-0.1.0-alpha.3-macos-universal.dmg
Debian, Ubuntu, Mint, Pop!_OS	the .deb for your processor (amd64 for most PCs)
Any Linux	the .AppImage or the .flatpak

The first start

These builds aren't signed by Microsoft or notarized by Apple yet, so your system warns you the first time.

• Windows: SmartScreen may say "Windows protected your PC". Click More info, then Run anyway. The installer needs no administrator rights.

• macOS: open the .dmg and drag Cold Open to Applications. The first time you open it, macOS refuses. Open System Settings ▸ Privacy & Security, scroll down to the message about Cold Open, and click Open Anyway. On macOS 12 to 14 you can also Control-click the app and choose Open. If macOS says the app is damaged, run this in Terminal, then try again:

  xattr -dr com.apple.quarantine "/Applications/Cold Open.app"
  

• Linux: sudo apt install ./cold-open_*.deb; or chmod +x ColdOpen-*.AppImage and run it; or flatpak install --user ColdOpen-*.flatpak. The Flatpak can open scripts in your home folder. For another drive, run flatpak override --user --filesystem=/path/to/drive io.github.theyungstump.coldopen.

The command-line tool

coldopen converts, exports, compares and repairs scripts, and runs an MCP server for AI agents (coldopen mcp).

• Windows installer: it's on your PATH. Open a new terminal.
• macOS: choose Install the command-line tool in the palette (Cmd+K).
• .deb: /usr/bin/coldopen.
• AppImage: ./ColdOpen-*.AppImage cli --help.
• Flatpak: flatpak run --command=coldopen io.github.theyungstump.coldopen.

Tell us how it went

• Share feedback… or Report a problem… in the app, or a GitHub issue.
• Discussions for how testing went, questions and ideas.
• Without a GitHub account.

Help us measure it: choose Measure performance in the palette, or run coldopen bench. It takes about two minutes and writes two small files to your Downloads folder, holding your computer's model names and the times, and nothing else. Please send them to us, especially from a Mac or Linux.

Please never attach a script you don't own. A short scene of your own that shows the problem is best.

Known issues

• macOS: double-clicking a .fountain, .fdx or .coldopen file starts Cold Open but doesn't open the file yet. Use Open (Cmd+O) instead.
• Windows: Cold Open appears in "Open with" for .fountain and .fdx files. Windows lets only you make it the default.
• The rest are in Known limitations.

Files

File	Size
ColdOpen-0.1.0-alpha.3-aarch64.AppImage	10.9 MB
ColdOpen-0.1.0-alpha.3-aarch64.flatpak	6.3 MB
ColdOpen-0.1.0-alpha.3-macos-arm64.dmg	6.3 MB
ColdOpen-0.1.0-alpha.3-macos-universal.dmg	14.9 MB
ColdOpen-0.1.0-alpha.3-macos-x64.dmg	8.7 MB
ColdOpen-0.1.0-alpha.3-mcp.mcpb	12.7 MB
ColdOpen-0.1.0-alpha.3-symbols.zip	118.8 MB
ColdOpen-0.1.0-alpha.3-third-party-licenses-linux-aarch64.txt	0.2 MB
ColdOpen-0.1.0-alpha.3-third-party-licenses-linux-x86_64.txt	0.2 MB
ColdOpen-0.1.0-alpha.3-windows-arm64-setup.exe	7.5 MB
ColdOpen-0.1.0-alpha.3-windows-arm64.zip	9.4 MB
ColdOpen-0.1.0-alpha.3-windows-x64-setup.exe	8.2 MB
ColdOpen-0.1.0-alpha.3-windows-x64.zip	10.1 MB
ColdOpen-0.1.0-alpha.3-x86_64.AppImage	11.8 MB
ColdOpen-0.1.0-alpha.3-x86_64.flatpak	7.2 MB
cold-open_0.1.0-alpha.3_amd64.deb	8.4 MB
cold-open_0.1.0-alpha.3_arm64.deb	7.2 MB

Check a download with sha256sum -c SHA256SUMS.txt --ignore-missing (Linux), shasum -a 256 -c SHA256SUMS.txt --ignore-missing (macOS) or Get-FileHash (Windows).

ColdOpen-0.1.0-alpha.3-symbols.zip isn't for installing: it lets the project read crash reports from this release. The third-party-licenses files list the licenses of the crates in the Linux builds, for building them from source. ColdOpen-0.1.0-alpha.3-mcp.mcpb is Cold Open's MCP server as a bundle, for AI clients that install MCP bundles.

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Cold Open 0.1.0-alpha.2

The second alpha of Cold Open, and the first we're inviting testers to: a free, open-source screenwriting app that reads and writes Fountain and .fdx files, paginates the same on every computer, and journals every keystroke, so a crash costs nothing.

This is an alpha. Keep copies of anything that matters. Your scripts are plain Fountain and .fdx files, so nothing you write here is locked in.

New here? The website has everything: the user guide, the install notes, and the tester guide, a 20-minute tour.

What's new since alpha.1

• Report a problem… in the palette, in About, and on the start screen. It opens a ready-filled GitHub issue in your browser, or our feedback form if you don't have a GitHub account, with Cold Open's version, your system and the renderer, and nothing from your script. Nothing is sent until you submit it yourself.
• Crash reports, if you want them.
  • If Cold Open crashes, it saves a short report on your computer, holding no script text, file names or user names.
  • At the next start it offers to show you the report, and you can send it, or not.
  • Never ask again turns reports off.
• Crash on purpose (to test recovery) in the palette closes Cold Open as a crash would, so you can see your work come back.
• The user guide and website, with a keyboard, command-line and command reference made from Cold Open's own code.
• Open the user guide in the palette and About.
• Interface size: if dialogs and panels are hard to read, Make the interface larger in the palette makes the whole window bigger, up to 200%.
• Every command's parameters are described, for agents and in the reference.
• The command-line tool's file details name Cold Open and the version on Windows.
• The full list is in the changelog.

Which file to download

Your computer	File
Windows 10 or 11 (most PCs)	ColdOpen-0.1.0-alpha.2-windows-x64-setup.exe
Windows on ARM (Surface Pro X, Snapdragon laptops)	ColdOpen-0.1.0-alpha.2-windows-arm64-setup.exe
Windows, without installing	the .zip for your processor
macOS 12 or later, Apple chip (M1, M2, M3…)	ColdOpen-0.1.0-alpha.2-macos-arm64.dmg
macOS 12 or later, Intel	ColdOpen-0.1.0-alpha.2-macos-x64.dmg (Apple menu ▸ About This Mac shows Processor for Intel, Chip for Apple)
Debian, Ubuntu, Mint, Pop!_OS	the .deb for your processor (amd64 for most PCs)
Any Linux	the .AppImage or the .flatpak

The first start

These builds aren't signed by Microsoft or notarized by Apple yet, so your system warns you the first time.

• Windows: SmartScreen may say "Windows protected your PC". Click More info, then Run anyway. The installer needs no administrator rights.

• macOS: open the .dmg and drag Cold Open to Applications. The first time you open it, macOS refuses. Open System Settings ▸ Privacy & Security, scroll down to the message about Cold Open, and click Open Anyway. On macOS 12 to 14 you can also Control-click the app and choose Open. If macOS says the app is damaged, run this in Terminal, then try again:

  xattr -dr com.apple.quarantine "/Applications/Cold Open.app"
  

• Linux: sudo apt install ./cold-open_*.deb; or chmod +x ColdOpen-*.AppImage and run it; or flatpak install --user ColdOpen-*.flatpak. The Flatpak can open scripts in your home folder. For another drive, run flatpak override --user --filesystem=/path/to/drive io.github.theyungstump.coldopen.

The command-line tool

coldopen converts, exports, compares and repairs scripts, and runs an MCP server for AI agents (coldopen mcp).

• Windows installer: it's on your PATH. Open a new terminal.
• macOS: choose Install the command-line tool in the palette (Cmd+K).
• .deb: /usr/bin/coldopen.
• AppImage: ./ColdOpen-*.AppImage cli --help.
• Flatpak: flatpak run --command=coldopen io.github.theyungstump.coldopen (or add alias coldopen='flatpak run --command=coldopen io.github.theyungstump.coldopen' to your shell).

Tell us how it went

• Report a problem… in the app, or a GitHub issue.
• Discussions for how testing went, questions and ideas.
• Without a GitHub account.

Help us measure it: choose Measure performance in the palette, or run coldopen bench. It takes about two minutes and writes two small files to your Downloads folder, holding your computer's model names and the times, and nothing else. Please send them to us, especially from a Mac or Linux.

Please never attach a script you don't own. A short scene of your own that shows the problem is best.

Known issues

• macOS: double-clicking a .fountain, .fdx or .coldopen file starts Cold Open but doesn't open the file yet. Use Open (Cmd+O) instead.
• macOS: scrolling the report view may stutter now and then. On a tester's Mac with alpha.1, a few frames in a hundred took over 20 ms with the GPU renderer, though most took about 6. This release measures it against the display's refresh, and we're checking it on real Macs.
• Windows: Cold Open appears in "Open with" for .fountain and .fdx files. Windows lets only you make it the default.
• The app's icon is a stand-in.
• The rest are in Known limitations.

Files

File	Size
ColdOpen-0.1.0-alpha.2-aarch64.AppImage	11.4 MB
ColdOpen-0.1.0-alpha.2-aarch64.flatpak	6.5 MB
ColdOpen-0.1.0-alpha.2-macos-arm64.dmg	7.6 MB
ColdOpen-0.1.0-alpha.2-macos-x64.dmg	9.0 MB
ColdOpen-0.1.0-alpha.2-symbols.zip	125.9 MB
ColdOpen-0.1.0-alpha.2-windows-arm64-setup.exe	7.7 MB
ColdOpen-0.1.0-alpha.2-windows-arm64.zip	9.7 MB
ColdOpen-0.1.0-alpha.2-windows-x64-setup.exe	8.3 MB
ColdOpen-0.1.0-alpha.2-windows-x64.zip	10.5 MB
ColdOpen-0.1.0-alpha.2-x86_64.AppImage	12.3 MB
ColdOpen-0.1.0-alpha.2-x86_64.flatpak	7.4 MB
cold-open_0.1.0-alpha.2_amd64.deb	8.9 MB
cold-open_0.1.0-alpha.2_arm64.deb	7.5 MB

Check a download with sha256sum -c SHA256SUMS.txt --ignore-missing (Linux), shasum -a 256 -c SHA256SUMS.txt --ignore-missing (macOS) or Get-FileHash (Windows).

ColdOpen-0.1.0-alpha.2-symbols.zip isn't for installing: it lets the project read crash reports from this release.

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Cold Open 0.1.0-alpha.1

The first alpha of Cold Open, for testers: a free, open-source screenwriting app that reads and writes Fountain and .fdx files, paginates the same on every computer, and journals every keystroke, so a crash costs nothing.

This is an alpha. Keep copies of anything that matters. Your scripts are plain Fountain and .fdx files, so nothing you write here is locked in.

Which file to download

Your computer	File
Windows 10 or 11 (most PCs)	ColdOpen-0.1.0-alpha.1-windows-x64-setup.exe
Windows on ARM (Surface Pro X, Snapdragon laptops)	ColdOpen-0.1.0-alpha.1-windows-arm64-setup.exe
Windows, without installing	the .zip for your processor
macOS 12 or later, Apple chip (M1, M2, M3…)	ColdOpen-0.1.0-alpha.1-macos-arm64.dmg
macOS 12 or later, Intel	ColdOpen-0.1.0-alpha.1-macos-x64.dmg (Apple menu ▸ About This Mac shows Processor for Intel, Chip for Apple)
Debian, Ubuntu, Mint, Pop!_OS	the .deb for your processor (amd64 for most PCs)
Any Linux	the .AppImage or the .flatpak

The first start

These builds aren't signed by Microsoft or notarized by Apple yet, so your system warns you the first time.

• Windows: SmartScreen may say "Windows protected your PC". Click More info, then Run anyway. The installer needs no administrator rights.

• macOS: open the .dmg and drag Cold Open to Applications. The first time you open it, macOS refuses. Open System Settings ▸ Privacy & Security, scroll down to the message about Cold Open, and click Open Anyway. On macOS 12 to 14 you can also Control-click the app and choose Open. If macOS says the app is damaged, run this in Terminal, then try again:

  xattr -dr com.apple.quarantine "/Applications/Cold Open.app"
  

• Linux: sudo apt install ./cold-open_*.deb; or chmod +x ColdOpen-*.AppImage and run it; or flatpak install --user ColdOpen-*.flatpak. The Flatpak can open scripts in your home folder. For another drive, run flatpak override --user --filesystem=/path/to/drive io.github.theyungstump.coldopen.

The command-line tool

coldopen converts, exports, compares and repairs scripts, and runs an MCP server for AI agents (coldopen mcp).

• Windows installer: it's on your PATH. Open a new terminal.
• macOS: choose Install the command-line tool in the palette (Cmd+K).
• .deb: /usr/bin/coldopen.
• AppImage: ./ColdOpen-*.AppImage cli --help.
• Flatpak: flatpak run --command=coldopen io.github.theyungstump.coldopen (or add alias coldopen='flatpak run --command=coldopen io.github.theyungstump.coldopen' to your shell).

Help us measure it

Choose Measure performance in the palette (Ctrl+K or Cmd+K), or run coldopen bench. It takes about two minutes and writes two small files to your Downloads folder, holding your computer's model names and the times, and nothing else. Please send them to us.

Known issues

• macOS: double-clicking a .fountain, .fdx or .coldopen file starts Cold Open but doesn't open the file yet. Use Open (Cmd+O) instead.
• macOS: scrolling the report view can stutter now and then. On a tester's Mac, a few frames in a hundred took over 20 ms with the GPU renderer, against our 16 ms budget; most took about 6. A fix is on the way.
• Windows: Cold Open appears in "Open with" for .fountain and .fdx files. Windows lets only you make it the default.
• The app's icon is a stand-in.

Files

File	Size
ColdOpen-0.1.0-alpha.1-aarch64.AppImage	11.3 MB
ColdOpen-0.1.0-alpha.1-aarch64.flatpak	6.4 MB
ColdOpen-0.1.0-alpha.1-macos-arm64.dmg	7.6 MB
ColdOpen-0.1.0-alpha.1-macos-x64.dmg	8.9 MB
ColdOpen-0.1.0-alpha.1-windows-arm64-setup.exe	7.6 MB
ColdOpen-0.1.0-alpha.1-windows-arm64.zip	9.6 MB
ColdOpen-0.1.0-alpha.1-windows-x64-setup.exe	8.2 MB
ColdOpen-0.1.0-alpha.1-windows-x64.zip	10.4 MB
ColdOpen-0.1.0-alpha.1-x86_64.AppImage	12.2 MB
ColdOpen-0.1.0-alpha.1-x86_64.flatpak	7.3 MB
cold-open_0.1.0-alpha.1_amd64.deb	8.8 MB
cold-open_0.1.0-alpha.1_arm64.deb	7.5 MB

Check a download with sha256sum -c SHA256SUMS.txt --ignore-missing (Linux), shasum -a 256 -c SHA256SUMS.txt --ignore-missing (macOS) or Get-FileHash (Windows).

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