diff --git a/.github/workflows/release.yaml b/.github/workflows/release.yaml
index 0ab3ac5..76c5b31 100644
--- a/.github/workflows/release.yaml
+++ b/.github/workflows/release.yaml
@@ -125,8 +125,8 @@ jobs:
           # Use Docker BuildKit
           export DOCKER_BUILDKIT=1
 
-          # Build the binary using our Dockerfile
-          docker/release/build.sh ${{ matrix.target }}
+          # Build the binary using our Dockerfile with version
+          docker/release/build.sh ${{ matrix.target }} ${{ github.event.inputs.version }}
 
           # Make sure dist directory exists and binary is there
           ls -la dist/
diff --git a/docker/release/build.sh b/docker/release/build.sh
index 2095591..a9e42e4 100755
--- a/docker/release/build.sh
+++ b/docker/release/build.sh
@@ -2,6 +2,14 @@
 set -euo pipefail
 
 TARGET=${1:-x86_64-unknown-linux-musl}
+VERSION=${2:-}
+
+# Build arguments for Docker
+BUILD_ARGS=""
+if [ -n "$VERSION" ]; then
+  BUILD_ARGS="--build-arg SANDBOX_AGENT_VERSION=$VERSION"
+  echo "Building with version: $VERSION"
+fi
 
 case $TARGET in
   x86_64-unknown-linux-musl)
@@ -36,9 +44,9 @@ case $TARGET in
 
 DOCKER_BUILDKIT=1
 if [ -n "$TARGET_STAGE" ]; then
-  docker build --target "$TARGET_STAGE" -f "docker/release/$DOCKERFILE" -t "sandbox-agent-builder-$TARGET" .
+  docker build --target "$TARGET_STAGE" $BUILD_ARGS -f "docker/release/$DOCKERFILE" -t "sandbox-agent-builder-$TARGET" .
 else
-  docker build -f "docker/release/$DOCKERFILE" -t "sandbox-agent-builder-$TARGET" .
+  docker build $BUILD_ARGS -f "docker/release/$DOCKERFILE" -t "sandbox-agent-builder-$TARGET" .
 fi
 
 CONTAINER_ID=$(docker create "sandbox-agent-builder-$TARGET")
diff --git a/docker/release/linux-x86_64.Dockerfile b/docker/release/linux-x86_64.Dockerfile
index f838b93..6145de9 100644
--- a/docker/release/linux-x86_64.Dockerfile
+++ b/docker/release/linux-x86_64.Dockerfile
@@ -66,6 +66,10 @@ WORKDIR /build
 # Build for x86_64
 FROM base AS x86_64-builder
 
+# Accept version as build arg
+ARG SANDBOX_AGENT_VERSION
+ENV SANDBOX_AGENT_VERSION=${SANDBOX_AGENT_VERSION}
+
 # Set up OpenSSL for x86_64 musl target
 ENV SSL_VER=1.1.1w
 RUN wget https://www.openssl.org/source/openssl-$SSL_VER.tar.gz \
diff --git a/docker/release/macos-aarch64.Dockerfile b/docker/release/macos-aarch64.Dockerfile
index 29e4b32..d85e64d 100644
--- a/docker/release/macos-aarch64.Dockerfile
+++ b/docker/release/macos-aarch64.Dockerfile
@@ -70,6 +70,10 @@ WORKDIR /build
 # Build for ARM64 macOS
 FROM base AS aarch64-builder
 
+# Accept version as build arg
+ARG SANDBOX_AGENT_VERSION
+ENV SANDBOX_AGENT_VERSION=${SANDBOX_AGENT_VERSION}
+
 # Install macOS ARM64 target
 RUN rustup target add aarch64-apple-darwin
 
diff --git a/docker/release/macos-x86_64.Dockerfile b/docker/release/macos-x86_64.Dockerfile
index 5a33b15..f705e00 100644
--- a/docker/release/macos-x86_64.Dockerfile
+++ b/docker/release/macos-x86_64.Dockerfile
@@ -70,6 +70,10 @@ WORKDIR /build
 # Build for x86_64 macOS
 FROM base AS x86_64-builder
 
+# Accept version as build arg
+ARG SANDBOX_AGENT_VERSION
+ENV SANDBOX_AGENT_VERSION=${SANDBOX_AGENT_VERSION}
+
 # Install macOS x86_64 target
 RUN rustup target add x86_64-apple-darwin
 
diff --git a/docker/release/windows.Dockerfile b/docker/release/windows.Dockerfile
index 2acabf2..3403a4d 100644
--- a/docker/release/windows.Dockerfile
+++ b/docker/release/windows.Dockerfile
@@ -26,6 +26,10 @@ RUN cd frontend/packages/inspector && pnpm exec vite build
 
 FROM rust:1.88.0
 
+# Accept version as build arg
+ARG SANDBOX_AGENT_VERSION
+ENV SANDBOX_AGENT_VERSION=${SANDBOX_AGENT_VERSION}
+
 # Install dependencies
 RUN apt-get update && apt-get install -y \
     llvm-14-dev \
diff --git a/sdks/cli/bin/sandbox-agent b/sdks/cli/bin/sandbox-agent
index 705af5d..9374244 100755
--- a/sdks/cli/bin/sandbox-agent
+++ b/sdks/cli/bin/sandbox-agent
@@ -1,21 +1,6 @@
 #!/usr/bin/env node
 const { execFileSync } = require("child_process");
 const path = require("path");
-const fs = require("fs");
-
-// Handle --version / -V at the launcher level to report npm package version
-// This ensures version matches what's installed via npm, not what's compiled into the binary
-const args = process.argv.slice(2);
-if (args.length === 1 && (args[0] === "--version" || args[0] === "-V")) {
-  const pkgJsonPath = path.join(__dirname, "..", "package.json");
-  try {
-    const pkgJson = JSON.parse(fs.readFileSync(pkgJsonPath, "utf-8"));
-    console.log(`sandbox-agent ${pkgJson.version}`);
-    process.exit(0);
-  } catch (e) {
-    // Fall through to binary if we can't read package.json
-  }
-}
 
 const PLATFORMS = {
   "darwin-arm64": "@sandbox-agent/cli-darwin-arm64",
@@ -34,7 +19,7 @@ if (!pkg) {
 try {
   const pkgPath = require.resolve(`${pkg}/package.json`);
   const bin = process.platform === "win32" ? "sandbox-agent.exe" : "sandbox-agent";
-  execFileSync(path.join(path.dirname(pkgPath), "bin", bin), args, { stdio: "inherit" });
+  execFileSync(path.join(path.dirname(pkgPath), "bin", bin), process.argv.slice(2), { stdio: "inherit" });
 } catch (e) {
   if (e.status !== undefined) process.exit(e.status);
   throw e;
diff --git a/server/packages/sandbox-agent/build.rs b/server/packages/sandbox-agent/build.rs
index 56e4ba0..170c05a 100644
--- a/server/packages/sandbox-agent/build.rs
+++ b/server/packages/sandbox-agent/build.rs
@@ -16,10 +16,14 @@ fn main() {
         .join("dist");
 
     println!("cargo:rerun-if-env-changed=SANDBOX_AGENT_SKIP_INSPECTOR");
+    println!("cargo:rerun-if-env-changed=SANDBOX_AGENT_VERSION");
     println!("cargo:rerun-if-changed={}", dist_dir.display());
 
-    let skip = env::var("SANDBOX_AGENT_SKIP_INSPECTOR").is_ok();
+    // Generate version constant from environment variable or fallback to Cargo.toml version
     let out_dir = PathBuf::from(env::var("OUT_DIR").expect("OUT_DIR"));
+    generate_version(&out_dir);
+
+    let skip = env::var("SANDBOX_AGENT_SKIP_INSPECTOR").is_ok();
     let out_file = out_dir.join("inspector_assets.rs");
 
     if skip {
@@ -61,3 +65,19 @@ fn quote_path(path: &Path) -> String {
         .replace('\\', "\\\\")
         .replace('"', "\\\"")
 }
+
+fn generate_version(out_dir: &Path) {
+    // Use SANDBOX_AGENT_VERSION env var if set, otherwise fall back to CARGO_PKG_VERSION
+    let version = env::var("SANDBOX_AGENT_VERSION")
+        .unwrap_or_else(|_| env::var("CARGO_PKG_VERSION").expect("CARGO_PKG_VERSION"));
+
+    let out_file = out_dir.join("version.rs");
+    let contents = format!(
+        "/// Version string for this build.\n\
+         /// Set via SANDBOX_AGENT_VERSION env var at build time, or falls back to Cargo.toml version.\n\
+         pub const VERSION: &str = \"{}\";\n",
+        version
+    );
+
+    fs::write(&out_file, contents).expect("write version.rs");
+}
diff --git a/server/packages/sandbox-agent/src/main.rs b/server/packages/sandbox-agent/src/main.rs
index c0a57ff..38db97e 100644
--- a/server/packages/sandbox-agent/src/main.rs
+++ b/server/packages/sandbox-agent/src/main.rs
@@ -4,6 +4,11 @@ use std::path::PathBuf;
 use std::sync::Arc;
 
 use clap::{Args, Parser, Subcommand};
+
+// Include the generated version constant
+mod build_version {
+    include!(concat!(env!("OUT_DIR"), "/version.rs"));
+}
 use reqwest::blocking::Client as HttpClient;
 use reqwest::Method;
 use sandbox_agent::router::{build_router_with_state, shutdown_servers};
@@ -34,7 +39,7 @@ const DEFAULT_PORT: u16 = 2468;
 
 #[derive(Parser, Debug)]
 #[command(name = "sandbox-agent", bin_name = "sandbox-agent")]
-#[command(about = "https://sandboxagent.dev", version)]
+#[command(about = "https://sandboxagent.dev", version = build_version::VERSION)]
 #[command(arg_required_else_help = true)]
 struct Cli {
     #[command(subcommand)]