Cursor - AI-powered Code Editor

Overview

Cursor is an AI-powered code editor built on VSCode. On NixOS, we use a custom package that extracts and patches the AppImage to work properly with the NixOS environment.

Installation

Cursor is installed via the NixOS system configuration:

# nixos/configuration.nix
environment.systemPackages = with pkgs; [
  (pkgs.callPackage ./packages/cursor/extracted.nix { })
];

Update Procedure

1. Check for New Version

Visit the Cursor Downloads page or check the changelog for the latest version.

2. Update Package Definition

Edit nixos/packages/cursor/extracted.nix:

let
  pname = "cursor";
  version = "1.6.45";  # Update this version number

  src = fetchurl {
    url = "https://downloads.cursor.com/production/COMMIT_HASH/linux/x64/Cursor-${version}-x86_64.AppImage";
    hash = "sha256-PLACEHOLDER";  # This will be updated in the next step
  };

Finding the download URL:

1. Go to https://cursor.com/download
2. Open browser DevTools (F12) → Network tab
3. Click the Linux download button
4. Copy the download URL from the network request
5. The URL format: https://downloads.cursor.com/production/{commit}/linux/x64/Cursor-{version}-x86_64.AppImage

3. Calculate SHA256 Hash

Use nix-prefetch-url to download and calculate the hash:

# Download and get SHA256 hash
nix-prefetch-url https://downloads.cursor.com/production/COMMIT_HASH/linux/x64/Cursor-1.6.45-x86_64.AppImage

# Convert to SRI format (sha256-...)
nix --extra-experimental-features 'nix-command' hash convert --hash-algo sha256 --to sri HASH_FROM_ABOVE

Update the hash field in extracted.nix with the SRI format hash (e.g., sha256-ABC123...=).

4. Build and Apply

# Build the new package
sudo nixos-rebuild switch --flake .#desktop

# Or for testing without system changes
nix build .#nixosConfigurations.desktop.config.environment.systemPackages -L

5. Verify Installation

cursor --version

Global AI Rules（人格・行動原則）

Claude Code / Gemini / Codex CLI と異なり、Cursor にはホームディレクトリ配下のグローバル指示ファイルという仕組みが存在しない（~/.cursor/AGENTS.md のようなパスは Cursor が読まない）。modules/home/claude/config/AGENTS.md を dotfiles から自動配備する対象に Cursor は含まれていない。理由と回避策は以下の通り。

• プロジェクト単位: Cursor はプロジェクトルートの AGENTS.md（フロントマターなしのプレーン Markdown）を自動的に読む。このリポジトリのようにルートに AGENTS.md があるプロジェクトでは、追加設定なしで人格・行動原則が反映される。.cursor/rules/*.mdc も同様にプロジェクト単位（<repo>/.cursor/rules/）で、$HOME/.cursor/rules/ はスコープ外。
• グローバル（全プロジェクト共通）: Cursor 上部メニュー → Cursor Settings → Rules → User Rules に手動で貼り付ける以外の方法がない。modules/home/claude/config/AGENTS.md の内容をコピーして貼り付ける（自動同期の仕組みはなく、内容を更新したら手動で再度貼り直す必要がある）。
• 参考: Cursor Docs - Rules

なお ai-guardrails が生成する ~/.cursor/rules/ai-guardrails.mdc（ホームディレクトリ直下への配置）も、上記と同じ理由でおそらく Cursor に読み込まれない。dotfiles では programs.ai-guardrails.installInstructionFiles = false により、この生成自体を無効化している。

NixOS-Specific Implementation

Automatic cursor-agent Patching

The Cursor package includes an automatic patcher for the cursor-agent node binaries. This is necessary because Cursor downloads its own Node.js binaries to ~/.local/share/cursor-agent/versions/, which are dynamically linked and won't work on NixOS without patching.

How it works:

1. When you launch Cursor, the wrapper script checks for cursor-agent directories
2. For each version directory containing an unpatched node binary:
   • Sets the correct ELF interpreter for NixOS
   • Sets the runtime library path (rpath)
   • Creates a .patched marker file to avoid re-patching

Location: nixos/packages/cursor/extracted.nix:130-161

Manual Patching (if needed)

If cursor-agent fails to run, you can manually patch the node binary:

# Get the NixOS dynamic linker path
INTERPRETER=$(nix --extra-experimental-features 'nix-command flakes' eval --raw 'nixpkgs#stdenv.cc.bintools.dynamicLinker')

# Get the library path
LIBPATH=$(nix --extra-experimental-features 'nix-command flakes' eval --raw 'nixpkgs#stdenv.cc.cc.lib.outPath')/lib

# Patch the binary
nix --extra-experimental-features 'nix-command flakes' run nixpkgs#patchelf -- \
  --set-interpreter "$INTERPRETER" \
  --set-rpath "$LIBPATH" \
  ~/.local/share/cursor-agent/versions/*/node

Troubleshooting

Issue: Could not start dynamically linked executable

Error message:

Could not start dynamically linked executable: /home/user/.local/share/cursor-agent/versions/.../node
NixOS cannot run dynamically linked executables intended for generic linux environments out of the box.

Solution:

1. The automatic patcher should handle this, but if it fails, use the manual patching steps above
2. Check if the .patched marker file exists in the cursor-agent version directory
3. Remove the .patched file and restart Cursor to trigger re-patching
4. Verify the patcher script is working: check the Cursor wrapper at /nix/store/.../bin/cursor

Issue: Build fails with makeCWrapper: Unknown argument --run

This error occurred in older versions when using makeWrapper --run. The current implementation uses a simple bash script wrapper instead.

Solution: Ensure you're using the latest version of nixos/packages/cursor/extracted.nix from this repository.

Issue: Wayland warnings on startup

Warning messages:

Warning: 'ozone-platform-hint' is not in the list of known options
Warning: 'enable-features' is not in the list of known options

Status: These warnings are harmless and can be ignored. They appear because we pass Wayland-specific flags to enable proper Wayland support. Cursor functions correctly despite these warnings.

Issue: Cursor doesn't start after update

Checklist:

1. Check if the AppImage was extracted correctly: ls -la /nix/store/*-cursor-*/
2. Verify the cursor binary is executable: file $(which cursor)
3. Check for error messages: cursor --verbose
4. Try rebuilding with verbose output: sudo nixos-rebuild switch --flake .#desktop --show-trace
5. Check the build logs: nix log /nix/store/...-cursor-*.drv

Issue: Cursor-agent updates fail

If Cursor attempts to update cursor-agent but fails:

1. Clear the cursor-agent directory:

   rm -rf ~/.local/share/cursor-agent
   

2. Restart Cursor - it will re-download and the patcher will handle the new version

Architecture Details

Package Structure

nixos/packages/cursor/
├── extracted.nix       # Main package definition (AppImage extraction approach)
└── default.nix        # Alternative package (AppImage wrapper approach - not used)

We use the extracted.nix approach because:

• Better control over the binary patching
• Can modify internal files (sudo-prompt, ripgrep, etc.)
• More predictable behavior with cursor-agent
• Full access to patch node_modules and resources

Key Dependencies

• autoPatchelfHook: Automatically patches ELF binaries
• asar: Unpacks/repacks VSCode's asar archives
• wrapGAppsHook: Sets up GTK/GLib environment variables
• patchelf: Runtime patching of cursor-agent binaries
• ripgrep: Replaced with Nix version for consistency

Build Phases

1. Extract: AppImage is extracted using appimageTools.extract
2. Patch: Asar archives are unpacked, files are patched (sudo-prompt, ripgrep)
3. Install: Files are copied to output, wrapper script is created
4. Fixup: autoPatchelfHook and wrapGAppsHook process the binaries
5. PostFixup: Additional library dependencies are added to the main binary

References

• Cursor Official Website
• Cursor Changelog
• NixOS Dynamic Linking Guide
• AppImage Tools Documentation