diff --git a/postinstall.mjs b/postinstall.mjs
index 5fe05f702..cdebb7e68 100644
--- a/postinstall.mjs
+++ b/postinstall.mjs
@@ -7,6 +7,60 @@ import { getPlatformPackageCandidates, getBinaryPath } from "./bin/platform.js";
 
 const require = createRequire(import.meta.url);
 
+const MIN_OPENCODE_VERSION = "1.4.0";
+
+/**
+ * Parse version string into numeric parts
+ * @param {string} version
+ * @returns {number[]}
+ */
+function parseVersion(version) {
+  return version
+    .replace(/^v/, "")
+    .split("-")[0]
+    .split(".")
+    .map((part) => Number.parseInt(part, 10) || 0);
+}
+
+/**
+ * Compare two version strings
+ * @param {string} current
+ * @param {string} minimum
+ * @returns {boolean} true if current >= minimum
+ */
+function compareVersions(current, minimum) {
+  const currentParts = parseVersion(current);
+  const minimumParts = parseVersion(minimum);
+  const length = Math.max(currentParts.length, minimumParts.length);
+
+  for (let index = 0; index < length; index++) {
+    const currentPart = currentParts[index] ?? 0;
+    const minimumPart = minimumParts[index] ?? 0;
+    if (currentPart > minimumPart) return true;
+    if (currentPart < minimumPart) return false;
+  }
+
+  return true;
+}
+
+/**
+ * Check if opencode version meets minimum requirement
+ * @returns {{ok: boolean, version: string | null}}
+ */
+function checkOpenCodeVersion() {
+  try {
+    const result = require("child_process").execSync("opencode --version", {
+      encoding: "utf-8",
+      stdio: ["pipe", "pipe", "ignore"],
+    });
+    const version = result.trim();
+    const ok = compareVersions(version, MIN_OPENCODE_VERSION);
+    return { ok, version };
+  } catch {
+    return { ok: true, version: null };
+  }
+}
+
 /**
  * Detect libc family on Linux
  */
@@ -36,7 +90,15 @@ function main() {
   const { platform, arch } = process;
   const libcFamily = getLibcFamily();
   const packageBaseName = getPackageBaseName();
-  
+
+  // Check opencode version requirement
+  const versionCheck = checkOpenCodeVersion();
+  if (versionCheck.version && !versionCheck.ok) {
+    console.warn(`⚠ oh-my-opencode requires OpenCode >= ${MIN_OPENCODE_VERSION}`);
+    console.warn(`  Detected: ${versionCheck.version}`);
+    console.warn(`  Please update OpenCode to avoid compatibility issues.`);
+  }
+
   try {
     const packageCandidates = getPlatformPackageCandidates({
       platform,
diff --git a/src/cli/doctor/constants.ts b/src/cli/doctor/constants.ts
index 9afaf5a88..39bab0568 100644
--- a/src/cli/doctor/constants.ts
+++ b/src/cli/doctor/constants.ts
@@ -37,7 +37,7 @@ export const EXIT_CODES = {
   FAILURE: 1,
 } as const
 
-export const MIN_OPENCODE_VERSION = "1.0.150"
+export const MIN_OPENCODE_VERSION = "1.4.0"
 
 export const PACKAGE_NAME = PLUGIN_NAME