diff --git a/Dockerfile b/Dockerfile
index 913fb33..9348293 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -9,7 +9,7 @@ ARG CODEX_DOC_MARKETPLACE_REF=f8da961328a85f267b4402566e127310370169da
 ARG CODEX_CODE_REVIEW_MARKETPLACE_REF=9e016edff016d58f4d64e0a5468220d35a0f657b
 
 # 安裝必要的工具
-RUN apk add --no-cache --no-check-certificate bash ca-certificates curl git jq util-linux
+RUN apk add --no-cache --no-check-certificate bash ca-certificates curl git jq nodejs
 
 # 安裝 Codex CLI 工具
 RUN install_script="$(mktemp)" \
@@ -27,8 +27,9 @@ RUN codex plugin marketplace add "https://gitea.jsc.idv.tw/plugins/doc.git" --re
     && codex plugin add "jsc@doc" \
     && codex plugin add "jsc@code-review"
 
+COPY app /app
 COPY entrypoint.sh /entrypoint.sh
 
-RUN chmod +x /entrypoint.sh
+RUN chmod +x /entrypoint.sh /app/main.js
 
 ENTRYPOINT ["/entrypoint.sh"]
diff --git a/app/main.js b/app/main.js
new file mode 100644
index 0000000..bfa0c75
--- /dev/null
+++ b/app/main.js
@@ -0,0 +1,193 @@
+#!/usr/bin/env node
+
+const fs = require("fs");
+const os = require("os");
+const path = require("path");
+const { spawn } = require("child_process");
+
+const DEFAULT_PROMPT = "請自我介紹";
+const createdPaths = new Set();
+
+function removeIfCreated(filePath) {
+  if (!filePath || !createdPaths.has(filePath)) {
+    return;
+  }
+
+  try {
+    fs.rmSync(filePath, { force: true });
+  } catch {
+    // Best-effort cleanup only.
+  }
+}
+
+function cleanup() {
+  for (const filePath of Array.from(createdPaths).reverse()) {
+    removeIfCreated(filePath);
+  }
+}
+
+function makeTempFile(dir, prefix) {
+  const random = `${Date.now()}-${process.pid}-${Math.random().toString(16).slice(2)}`;
+  const filePath = path.join(dir, `${prefix}.${random}`);
+  const fd = fs.openSync(filePath, "wx", 0o600);
+  fs.closeSync(fd);
+  createdPaths.add(filePath);
+  return filePath;
+}
+
+function appendGithubOutput(status, output) {
+  const outputFile = process.env.GITHUB_OUTPUT;
+  if (!outputFile) {
+    return;
+  }
+
+  let delimiter;
+  do {
+    delimiter = `CODEX_OUTPUT_${Math.random().toString(36).slice(2)}${Date.now()}`;
+  } while (output.includes(delimiter));
+
+  fs.appendFileSync(
+    outputFile,
+    `status=${status}\noutput<<${delimiter}\n${output}${output.endsWith("\n") ? "" : "\n"}${delimiter}\n`,
+    { encoding: "utf8", mode: 0o600 },
+  );
+}
+
+function fail(message, code = 1) {
+  console.error(message);
+  appendGithubOutput("failed", message);
+  cleanup();
+  process.exit(code);
+}
+
+function validateAuth(encodedAuth, authFile) {
+  const decoded = Buffer.from(encodedAuth, "base64");
+
+  if (decoded.length === 0 && encodedAuth.length > 0) {
+    fail("OAUTH must be valid base64 encoded Codex auth.json.");
+  }
+
+  const normalized = encodedAuth.replace(/\s+/g, "");
+  if (decoded.toString("base64").replace(/=+$/, "") !== normalized.replace(/=+$/, "")) {
+    fail("OAUTH must be valid base64 encoded Codex auth.json.");
+  }
+
+  fs.writeFileSync(authFile, decoded, { mode: 0o600 });
+
+  let parsed;
+  try {
+    parsed = JSON.parse(decoded.toString("utf8"));
+  } catch {
+    fail("Decoded OAUTH must be a JSON object.");
+  }
+
+  if (!parsed || Array.isArray(parsed) || typeof parsed !== "object") {
+    fail("Decoded OAUTH must be a JSON object.");
+  }
+}
+
+function runCodex(model, prompt) {
+  return new Promise((resolve) => {
+    const child = spawn(
+      "codex",
+      [
+        "exec",
+        "--dangerously-bypass-approvals-and-sandbox",
+        "--skip-git-repo-check",
+        "--model",
+        model,
+        prompt,
+      ],
+      { stdio: ["ignore", "pipe", "pipe"] },
+    );
+
+    let output = "";
+
+    child.stdout.on("data", (chunk) => {
+      process.stdout.write(chunk);
+      output += chunk.toString();
+    });
+
+    child.stderr.on("data", (chunk) => {
+      process.stdout.write(chunk);
+      output += chunk.toString();
+    });
+
+    child.on("error", (error) => {
+      output += `${error.message}\n`;
+      resolve({ status: 1, output });
+    });
+
+    child.on("close", (code) => {
+      resolve({ status: code ?? 1, output });
+    });
+  });
+}
+
+async function main() {
+  process.on("exit", cleanup);
+  process.on("SIGINT", () => {
+    cleanup();
+    process.exit(130);
+  });
+  process.on("SIGTERM", () => {
+    cleanup();
+    process.exit(143);
+  });
+
+  const oauth = process.env.OAUTH || "";
+  const model = process.env.MODEL || "";
+  const codexHome = process.env.CODEX_HOME || "/root/.codex";
+  const prompt = process.env.PROMPT || DEFAULT_PROMPT;
+
+  if (!oauth) {
+    fail("OAUTH is required: provide base64 encoded Codex auth.json.");
+  }
+
+  if (!model) {
+    fail("MODEL is required.");
+  }
+
+  try {
+    fs.mkdirSync(codexHome, { recursive: true, mode: 0o700 });
+  } catch {
+    fail("Unable to create CODEX_HOME.");
+  }
+
+  const authFile = makeTempFile(codexHome, "auth");
+  const authPath = path.join(codexHome, "auth.json");
+  const lockPath = path.join(os.tmpdir(), `codex-auth-${Buffer.from(codexHome).toString("hex")}.lock`);
+
+  let lockHandle;
+  try {
+    lockHandle = fs.openSync(lockPath, "wx", 0o600);
+    createdPaths.add(lockPath);
+  } catch {
+    fail("Unable to lock Codex auth.json.");
+  }
+
+  validateAuth(oauth, authFile);
+
+  if (fs.existsSync(authPath)) {
+    fail("Refusing to overwrite existing Codex auth.json.");
+  }
+
+  fs.copyFileSync(authFile, authPath);
+  fs.chmodSync(authPath, 0o600);
+  createdPaths.add(authPath);
+  removeIfCreated(authFile);
+
+  const result = await runCodex(model, prompt);
+  appendGithubOutput(result.status === 0 ? "completed" : "failed", result.output);
+
+  if (lockHandle !== undefined) {
+    fs.closeSync(lockHandle);
+  }
+
+  cleanup();
+  process.exit(result.status);
+}
+
+main().catch((error) => {
+  fail(error instanceof Error ? error.message : String(error));
+});
diff --git a/entrypoint.sh b/entrypoint.sh
index 5b5f268..b7c1b53 100644
--- a/entrypoint.sh
+++ b/entrypoint.sh
@@ -1,85 +1,7 @@
 #!/bin/bash
 
-set -eo pipefail
+set -euo pipefail
 
-die() {
-  echo "$1" >&2
-  exit 1
-}
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 
-cleanup() {
-  rm -f "${auth_file:-}" "${auth_path:-}" "${auth_lock:-}" "${codex_output:-}"
-}
-
-trap cleanup EXIT
-
-if [[ -z "${OAUTH:-}" ]]; then
-  die "OAUTH is required: provide base64 encoded Codex auth.json."
-fi
-
-if [[ -z "${MODEL:-}" ]]; then
-  die "MODEL is required."
-fi
-
-CODEX_HOME="${CODEX_HOME:-/root/.codex}"
-PROMPT="${PROMPT:-請自我介紹}"
-mkdir -p "$CODEX_HOME" || die "Unable to create CODEX_HOME."
-umask 077
-
-auth_file="$(mktemp "$CODEX_HOME/auth.XXXXXX")"
-auth_path="$CODEX_HOME/auth.json"
-auth_lock="$(mktemp "$CODEX_HOME/auth.lock.XXXXXX")"
-
-exec 9>"$auth_lock"
-flock -n 9 || die "Unable to lock Codex auth.json."
-
-if ! printf '%s\n' "$OAUTH" | base64 -d > "$auth_file"; then
-  die "OAUTH must be valid base64 encoded Codex auth.json."
-fi
-
-if ! jq -e 'type == "object"' "$auth_file" >/dev/null; then
-  die "Decoded OAUTH must be a JSON object."
-fi
-
-if [[ -e "$auth_path" ]]; then
-  die "Refusing to overwrite existing Codex auth.json."
-fi
-
-install -m 600 "$auth_file" "$auth_path"
-rm -f "$auth_file"
-
-codex_output="$(mktemp)"
-
-if codex exec \
-  --dangerously-bypass-approvals-and-sandbox \
-  --skip-git-repo-check \
-  --model "$MODEL" \
-  "$PROMPT" 2>&1 | tee "$codex_output"; then
-  codex_status=0
-else
-  codex_status="${PIPESTATUS[0]}"
-fi
-
-if [[ -n "${GITHUB_OUTPUT:-}" ]]; then
-  while :; do
-    output_delimiter="CODEX_OUTPUT_$(mktemp -u XXXXXXXXXXXXXXXX)"
-
-    if ! grep -qxF "$output_delimiter" "$codex_output"; then
-      break
-    fi
-  done
-
-  if [[ "$codex_status" -eq 0 ]]; then
-    echo "status=completed" >> "$GITHUB_OUTPUT"
-  else
-    echo "status=failed" >> "$GITHUB_OUTPUT"
-  fi
-
-  {
-    echo "output<<$output_delimiter"
-    cat "$codex_output"
-    echo "$output_delimiter"
-  } >> "$GITHUB_OUTPUT"
-fi
-
-exit "$codex_status"
+exec node "$SCRIPT_DIR/app/main.js"