fix(tui): externalize koffi from bun binary builds

Changed koffi import from top-level to dynamic require in
enableWindowsVTInput() and added --external koffi to bun build.
This prevents embedding all 18 platform .node files (~74MB) into
every compiled binary. For Windows builds, only the win32_x64
koffi.node is shipped alongside the binary.

Binary size reduction: darwin-arm64 142MB -> 67MB, archive 43MB -> 28MB.

packages/coding-agent/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- Externalized koffi from bun binary builds, reducing archive sizes by ~15MB per platform (e.g. darwin-arm64: 43MB -> 28MB). Koffi's Windows-only `.node` file is now shipped alongside the Windows binary only.
+
 ## [0.54.0] - 2026-02-19
 
 ### Added

packages/tui/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- Changed koffi import from top-level to dynamic require in `enableWindowsVTInput()` to prevent bun from embedding all 18 platform `.node` files (~74MB) into every compiled binary. Koffi is only needed on Windows.
+
 ## [0.54.0] - 2026-02-19
 
 ## [0.53.1] - 2026-02-19

packages/tui/src/terminal.ts

@@ -1,5 +1,4 @@
 import * as fs from "node:fs";
-import koffi from "koffi";
 import { setKittyProtocolActive } from "./keys.js";
 import { StdinBuffer } from "./stdin-buffer.js";
 
@@ -174,6 +173,10 @@ export class ProcessTerminal implements Terminal {
 	private enableWindowsVTInput(): void {
 		if (process.platform !== "win32") return;
 		try {
+			// Dynamic require to avoid bundling koffi's 74MB of cross-platform
+			// native binaries into every compiled binary. Koffi is only needed
+			// on Windows for VT input support.
+			const koffi = require("koffi");
 			const k32 = koffi.load("kernel32.dll");
 			const GetStdHandle = k32.func("void* __stdcall GetStdHandle(int)");
 			const GetConsoleMode = k32.func("bool __stdcall GetConsoleMode(void*, _Out_ uint32_t*)");

scripts/build-binaries.sh

@@ -102,10 +102,14 @@ fi
 
 for platform in "${PLATFORMS[@]}"; do
     echo "Building for $platform..."
+    # Externalize koffi to avoid embedding all 18 platform .node files (~74MB)
+    # into every binary. Koffi is only used on Windows for VT input and the
+    # call site has a try/catch fallback. For Windows builds, we copy the
+    # appropriate .node file alongside the binary below.
     if [[ "$platform" == "windows-x64" ]]; then
-        bun build --compile --target=bun-$platform ./dist/cli.js --outfile binaries/$platform/pi.exe
+        bun build --compile --external koffi --target=bun-$platform ./dist/cli.js --outfile binaries/$platform/pi.exe
     else
-        bun build --compile --target=bun-$platform ./dist/cli.js --outfile binaries/$platform/pi
+        bun build --compile --external koffi --target=bun-$platform ./dist/cli.js --outfile binaries/$platform/pi
     fi
 done
 
@@ -122,6 +126,14 @@ for platform in "${PLATFORMS[@]}"; do
     cp -r dist/core/export-html binaries/$platform/
     cp -r docs binaries/$platform/
     cp -r examples binaries/$platform/
+
+    # Copy koffi native module for Windows (needed for VT input support)
+    if [[ "$platform" == "windows-x64" ]]; then
+        mkdir -p binaries/$platform/node_modules/koffi/build/koffi/win32_x64
+        cp ../../node_modules/koffi/index.js binaries/$platform/node_modules/koffi/
+        cp ../../node_modules/koffi/package.json binaries/$platform/node_modules/koffi/
+        cp ../../node_modules/koffi/build/koffi/win32_x64/koffi.node binaries/$platform/node_modules/koffi/build/koffi/win32_x64/
+    fi
 done
 
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