diff --git a/Dockerfile b/Dockerfile
index e79f2d9..37032f9 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-# syntax=docker/dockerfile:1
+# syntax=docker/dockerfile:1.7
 
 # ── Stage 1: Build ────────────────────────────────────────────
 FROM rust:1.93-slim-trixie@sha256:9663b80a1621253d30b146454f903de48f0af925c967be48c84745537cd35d8b AS builder
@@ -6,27 +6,30 @@ FROM rust:1.93-slim-trixie@sha256:9663b80a1621253d30b146454f903de48f0af925c967be
 WORKDIR /app
 
 # Install build dependencies
-RUN apt-get update && apt-get install -y \
-    pkg-config \
+RUN --mount=type=cache,target=/var/cache/apt,sharing=locked \
+    --mount=type=cache,target=/var/lib/apt,sharing=locked \
+    apt-get update && apt-get install -y \
+        pkg-config \
     && rm -rf /var/lib/apt/lists/*
 
 # 1. Copy manifests to cache dependencies
 COPY Cargo.toml Cargo.lock ./
 # Create dummy main.rs to build dependencies
 RUN mkdir src && echo "fn main() {}" > src/main.rs
-RUN --mount=type=cache,target=/usr/local/cargo/registry \
-    --mount=type=cache,target=/usr/local/cargo/git \
+RUN --mount=type=cache,id=zeroclaw-cargo-registry,target=/usr/local/cargo/registry,sharing=locked \
+    --mount=type=cache,id=zeroclaw-cargo-git,target=/usr/local/cargo/git,sharing=locked \
+    --mount=type=cache,id=zeroclaw-target,target=/app/target,sharing=locked \
     cargo build --release --locked
 RUN rm -rf src
 
 # 2. Copy source code
 COPY . .
-# Touch main.rs to force rebuild
-RUN touch src/main.rs
-RUN --mount=type=cache,target=/usr/local/cargo/registry \
-    --mount=type=cache,target=/usr/local/cargo/git \
+RUN --mount=type=cache,id=zeroclaw-cargo-registry,target=/usr/local/cargo/registry,sharing=locked \
+    --mount=type=cache,id=zeroclaw-cargo-git,target=/usr/local/cargo/git,sharing=locked \
+    --mount=type=cache,id=zeroclaw-target,target=/app/target,sharing=locked \
     cargo build --release --locked && \
-    strip target/release/zeroclaw
+    cp target/release/zeroclaw /app/zeroclaw && \
+    strip /app/zeroclaw
 
 # ── Stage 2: Permissions & Config Prep ───────────────────────
 FROM busybox:1.37@sha256:b3255e7dfbcd10cb367af0d409747d511aeb66dfac98cf30e97e87e4207dd76f AS permissions
@@ -35,7 +38,7 @@ RUN mkdir -p /zeroclaw-data/.zeroclaw /zeroclaw-data/workspace
 
 # Create minimal config for PRODUCTION (allows binding to public interfaces)
 # NOTE: Provider configuration must be done via environment variables at runtime
-RUN cat > /zeroclaw-data/.zeroclaw/config.toml << 'EOF'
+RUN cat > /zeroclaw-data/.zeroclaw/config.toml <<EOF
 workspace_dir = "/zeroclaw-data/workspace"
 config_path = "/zeroclaw-data/.zeroclaw/config.toml"
 api_key = ""
@@ -65,7 +68,7 @@ RUN apt-get update && apt-get install -y \
     && rm -rf /var/lib/apt/lists/*
 
 COPY --from=permissions /zeroclaw-data /zeroclaw-data
-COPY --from=builder /app/target/release/zeroclaw /usr/local/bin/zeroclaw
+COPY --from=builder /app/zeroclaw /usr/local/bin/zeroclaw
 
 # Overwrite minimal config with DEV template (Ollama defaults)
 COPY dev/config.template.toml /zeroclaw-data/.zeroclaw/config.toml
@@ -92,7 +95,7 @@ CMD ["gateway", "--port", "3000", "--host", "[::]"]
 # ── Stage 4: Production Runtime (Distroless) ─────────────────
 FROM gcr.io/distroless/cc-debian13:nonroot@sha256:84fcd3c223b144b0cb6edc5ecc75641819842a9679a3a58fd6294bec47532bf7 AS release
 
-COPY --from=builder /app/target/release/zeroclaw /usr/local/bin/zeroclaw
+COPY --from=builder /app/zeroclaw /usr/local/bin/zeroclaw
 COPY --from=permissions /zeroclaw-data /zeroclaw-data
 
 # Environment setup
diff --git a/dev/README.md b/dev/README.md
index 12fcb4b..427b566 100644
--- a/dev/README.md
+++ b/dev/README.md
@@ -163,5 +163,7 @@ Note: local `deny` focuses on license/source policy; advisory scanning is handle
 ### Build cache notes
 
 - Both `Dockerfile` and `dev/ci/Dockerfile` use BuildKit cache mounts for Cargo registry/git data.
+- The root `Dockerfile` also caches Rust `target/` (`id=zeroclaw-target`) to speed repeat local image builds.
 - Local CI reuses named Docker volumes for Cargo registry/git and target outputs.
+- `./dev/ci.sh docker-smoke` and `./dev/ci.sh all` now use `docker buildx` local cache at `.cache/buildx-smoke` when available.
 - The CI image keeps Rust toolchain defaults from `rust:1.92-slim` and installs pinned toolchain `1.92.0` (no custom `CARGO_HOME`/`RUSTUP_HOME` overrides), preventing repeated toolchain bootstrapping on each run.
diff --git a/dev/ci.sh b/dev/ci.sh
index 61bf73b..a348a19 100755
--- a/dev/ci.sh
+++ b/dev/ci.sh
@@ -11,12 +11,32 @@ else
 fi
 
 compose_cmd=(docker compose -f "$COMPOSE_FILE")
+SMOKE_CACHE_DIR="${SMOKE_CACHE_DIR:-.cache/buildx-smoke}"
 
 run_in_ci() {
   local cmd="$1"
   "${compose_cmd[@]}" run --rm local-ci bash -c "$cmd"
 }
 
+build_smoke_image() {
+  if docker buildx version >/dev/null 2>&1; then
+    mkdir -p "$SMOKE_CACHE_DIR"
+    local build_args=(
+      --load
+      --target dev
+      --cache-to "type=local,dest=$SMOKE_CACHE_DIR,mode=max"
+      -t zeroclaw-local-smoke:latest
+      .
+    )
+    if [ -f "$SMOKE_CACHE_DIR/index.json" ]; then
+      build_args=(--cache-from "type=local,src=$SMOKE_CACHE_DIR" "${build_args[@]}")
+    fi
+    docker buildx build "${build_args[@]}"
+  else
+    DOCKER_BUILDKIT=1 docker build --target dev -t zeroclaw-local-smoke:latest .
+  fi
+}
+
 print_help() {
   cat <<'EOF'
 ZeroClaw Local CI in Docker
@@ -88,7 +108,7 @@ case "$1" in
     ;;
 
   docker-smoke)
-    docker build --target dev -t zeroclaw-local-smoke:latest .
+    build_smoke_image
     docker run --rm zeroclaw-local-smoke:latest --version
     ;;
 
@@ -98,7 +118,7 @@ case "$1" in
     run_in_ci "cargo build --release --locked --verbose"
     run_in_ci "cargo deny check licenses sources"
     run_in_ci "cargo audit"
-    docker build --target dev -t zeroclaw-local-smoke:latest .
+    build_smoke_image
     docker run --rm zeroclaw-local-smoke:latest --version
     ;;
 
diff --git a/src/channels/mod.rs b/src/channels/mod.rs
index fc9a7d2..d63f63d 100644
--- a/src/channels/mod.rs
+++ b/src/channels/mod.rs
@@ -227,7 +227,7 @@ async fn process_channel_message(ctx: Arc<ChannelRuntimeContext>, msg: traits::C
                 truncate_with_ellipsis(&response, 80)
             );
             if let Some(channel) = target_channel.as_ref() {
-                if let Err(e) = channel.send(&response, &msg.channel).await {
+                if let Err(e) = channel.send(&response, &msg.reply_target).await {
                     eprintln!("  ❌ Failed to reply on {}: {e}", channel.name());
                 }
             }