diff --git a/.github/workflows/dev-binary.yml b/.github/workflows/dev-binary.yml
new file mode 100644
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+++ b/.github/workflows/dev-binary.yml
@@ -0,0 +1,138 @@
+name: Dev binary
+
+# Builds unsigned, untagged herdr binaries from the current branch so they can be
+# downloaded and swapped in manually. Mirrors the release workflow's build job
+# (same targets, same Zig/libghostty-vt settings) but publishes nothing: the
+# binaries are uploaded as workflow artifacts only.
+
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - claude/**
+
+permissions:
+  contents: read
+
+env:
+  FORCE_JAVASCRIPT_ACTIONS_TO_NODE24: true
+  RUST_TOOLCHAIN_VERSION: 1.96.1
+
+concurrency:
+  group: dev-binary-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  build:
+    permissions:
+      contents: read
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - target: x86_64-unknown-linux-musl
+            os: ubuntu-latest
+            name: herdr-linux-x86_64
+          - target: aarch64-unknown-linux-musl
+            os: ubuntu-latest
+            name: herdr-linux-aarch64
+          - target: x86_64-apple-darwin
+            os: macos-latest
+            name: herdr-macos-x86_64
+          - target: aarch64-apple-darwin
+            os: macos-latest
+            name: herdr-macos-aarch64
+
+    runs-on: ${{ matrix.os }}
+    env:
+      LIBGHOSTTY_VT_OPTIMIZE: ReleaseFast
+      LIBGHOSTTY_VT_SIMD: 'true'
+
+    steps:
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
+        with:
+          persist-credentials: false
+
+      - name: Install Rust
+        uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8 # v1
+        with:
+          toolchain: ${{ env.RUST_TOOLCHAIN_VERSION }}
+          targets: ${{ matrix.target }}
+
+      - name: Install Zig
+        if: runner.os != 'macOS'
+        uses: mlugg/setup-zig@d1434d08867e3ee9daa34448df10607b98908d29 # v2.2.1
+        with:
+          version: 0.15.2
+
+      - name: Restore Homebrew Zig cache
+        if: runner.os == 'macOS'
+        uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830 # v4
+        with:
+          path: ~/Library/Caches/Homebrew/downloads
+          key: homebrew-zig-0.15-${{ runner.os }}-${{ runner.arch }}
+          restore-keys: |
+            homebrew-zig-0.15-${{ runner.os }}-
+
+      - name: Install patched Zig on macOS
+        if: runner.os == 'macOS'
+        run: |
+          HOMEBREW_NO_AUTO_UPDATE=1 brew install zig@0.15
+          echo "$(brew --prefix zig@0.15)/bin" >> "$GITHUB_PATH"
+          "$(brew --prefix zig@0.15)/bin/zig" version
+
+      - name: Prefer official Ubuntu mirrors over Azure
+        if: runner.os == 'Linux'
+        run: |
+          if [ -f /etc/apt/apt-mirrors.txt ]; then
+            sudo sed -i '/azure.archive.ubuntu.com/d' /etc/apt/apt-mirrors.txt
+            echo "Using apt mirrors:"
+            cat /etc/apt/apt-mirrors.txt
+          fi
+
+      - name: Install Linux build tools
+        if: runner.os == 'Linux'
+        run: |
+          sudo find /etc/apt/sources.list.d -type f \( -iname '*microsoft*' -o -iname '*azure-cli*' \) -print -delete
+          sudo apt-get update
+          sudo apt-get install -y cmake ninja-build musl-tools gcc-aarch64-linux-gnu crossbuild-essential-arm64
+
+      - name: Install macOS build tools
+        if: runner.os == 'macOS'
+        run: HOMEBREW_NO_AUTO_UPDATE=1 brew install cmake ninja
+
+      - name: Set Linux aarch64 linker
+        if: matrix.target == 'aarch64-unknown-linux-musl'
+        run: echo "CARGO_TARGET_AARCH64_UNKNOWN_LINUX_MUSL_LINKER=aarch64-linux-gnu-gcc" >> $GITHUB_ENV
+
+      - name: Cache Rust artifacts
+        uses: Swatinem/rust-cache@e18b497796c12c097a38f9edb9d0641fb99eee32 # v2
+        with:
+          key: dev-binary-${{ matrix.target }}
+
+      - name: Remove Zig caches
+        run: rm -rf .zig-cache vendor/libghostty-vt/.zig-cache vendor/libghostty-vt/zig-out
+
+      - name: Build
+        run: cargo build --release --locked --target ${{ matrix.target }}
+
+      - name: Rename binary
+        run: cp target/${{ matrix.target }}/release/herdr ${{ matrix.name }}
+
+      - name: Record build provenance
+        run: |
+          {
+            echo "commit=${GITHUB_SHA}"
+            echo "target=${{ matrix.target }}"
+            echo "built_at=$(date -u +%Y-%m-%dT%H:%M:%SZ)"
+          } > ${{ matrix.name }}.provenance.txt
+          ./${{ matrix.name }} --version >> ${{ matrix.name }}.provenance.txt 2>&1 || true
+          cat ${{ matrix.name }}.provenance.txt
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7
+        with:
+          name: ${{ matrix.name }}
+          path: |
+            ${{ matrix.name }}
+            ${{ matrix.name }}.provenance.txt