diff --git a/bin/oh-my-opencode.js b/bin/oh-my-opencode.js
index 1a712c9c6..b15583085 100755
--- a/bin/oh-my-opencode.js
+++ b/bin/oh-my-opencode.js
@@ -6,6 +6,7 @@ import { spawnSync } from "node:child_process";
 import { readFileSync } from "node:fs";
 import { createRequire } from "node:module";
 import { basename } from "node:path";
+import { fileURLToPath } from "node:url";
 import {
   getPlatformPackageCandidates,
   getBinaryPath,
@@ -90,6 +91,10 @@ function getWrapperPackageName() {
   }
 }
 
+function getWrapperPackageRoot() {
+  return fileURLToPath(new URL("..", import.meta.url));
+}
+
 /**
  * Determine which bin name the user invoked us with (oh-my-opencode, oh-my-openagent, omo, lazycodex).
  * Propagated to the compiled CLI binary via OMO_INVOCATION_NAME so it can route accordingly
@@ -155,6 +160,7 @@ function main() {
   const childEnv = {
     ...process.env,
     OMO_INVOCATION_NAME: invocationName,
+    OMO_WRAPPER_PACKAGE_ROOT: getWrapperPackageRoot(),
   };
 
   for (let index = 0; index < resolvedBinaries.length; index += 1) {
diff --git a/bin/oh-my-opencode.test.ts b/bin/oh-my-opencode.test.ts
index 692ee7434..8de969372 100644
--- a/bin/oh-my-opencode.test.ts
+++ b/bin/oh-my-opencode.test.ts
@@ -2,7 +2,7 @@
 
 import { afterEach, describe, expect, test } from "bun:test";
 import { spawnSync } from "node:child_process";
-import { chmod, cp, mkdir, mkdtemp, readFile, rm, symlink, writeFile } from "node:fs/promises";
+import { chmod, cp, mkdir, mkdtemp, readFile, realpath, rm, symlink, writeFile } from "node:fs/promises";
 import { tmpdir } from "node:os";
 import { dirname, join } from "node:path";
 import { fileURLToPath } from "node:url";
@@ -33,6 +33,7 @@ describe("lazycodex bin wrapper", () => {
     // #then
     expect(result.status).toBe(23);
     expect((await readFile(join(fixture.captureDir, "env"), "utf8")).trim()).toBe("lazycodex");
+    expect(await canonicalizePackageRootCapture(fixture)).toBe(await realpath(fixture.root));
     expect((await readFile(join(fixture.captureDir, "args"), "utf8")).trim().split("\n")).toEqual([
       "install",
       "--no-tui",
@@ -57,6 +58,7 @@ describe("lazycodex bin wrapper", () => {
     // #then
     expect(result.status).toBe(23);
     expect((await readFile(join(fixture.captureDir, "env"), "utf8")).trim()).toBe("lazycodex");
+    expect(await canonicalizePackageRootCapture(fixture)).toBe(await realpath(fixture.root));
     expect((await readFile(join(fixture.captureDir, "args"), "utf8")).trim().split("\n")).toEqual([
       "install",
       "--no-tui",
@@ -81,6 +83,7 @@ describe("lazycodex bin wrapper", () => {
     // #then
     expect(result.status).toBe(23);
     expect((await readFile(join(fixture.captureDir, "env"), "utf8")).trim()).toBe("lazycodex");
+    expect(await canonicalizePackageRootCapture(fixture)).toBe(await realpath(fixture.root));
     expect((await readFile(join(fixture.captureDir, "args"), "utf8")).trim().split("\n")).toEqual([
       "install",
       "--no-tui",
@@ -130,10 +133,15 @@ async function createLazyCodexFixture(options: { packageName?: string; wrapperFi
     captureDir,
     fakeBinDir,
     lazycodexBin: join(binDir, "lazycodex"),
+    root,
     wrapperBin,
   };
 }
 
+async function canonicalizePackageRootCapture(fixture: { readonly captureDir: string }): Promise<string> {
+  return realpath((await readFile(join(fixture.captureDir, "wrapper-root"), "utf8")).trim());
+}
+
 async function writePlatformPackages(root: string): Promise<void> {
   const packages = getPlatformPackageCandidates({
     platform: process.platform,
@@ -149,6 +157,7 @@ async function writePlatformPackages(root: string): Promise<void> {
       [
         "#!/bin/sh",
         "printf '%s\\n' \"$OMO_INVOCATION_NAME\" > \"$CAPTURE_DIR/env\"",
+        "printf '%s\\n' \"$OMO_WRAPPER_PACKAGE_ROOT\" > \"$CAPTURE_DIR/wrapper-root\"",
         "printf '%s\\n' \"$@\" > \"$CAPTURE_DIR/args\"",
         "exit 23",
         "",
diff --git a/src/cli/install-codex/install-codex.test.ts b/src/cli/install-codex/install-codex.test.ts
index 4b4afb193..5b6967659 100644
--- a/src/cli/install-codex/install-codex.test.ts
+++ b/src/cli/install-codex/install-codex.test.ts
@@ -5,7 +5,7 @@ import { describe, expect, test } from "bun:test"
 import { mkdir, mkdtemp, readdir, readFile, readlink, rm, stat, writeFile } from "node:fs/promises"
 import { tmpdir } from "node:os"
 import { join } from "node:path"
-import { findRepoRootFromImporter, resolveCodexInstallerBinDir, runCodexInstaller } from "./install-codex"
+import { findRepoRoot, findRepoRootFromImporter, resolveCodexInstallerBinDir, runCodexInstaller } from "./install-codex"
 
 const EXPECTED_OMO_COMPONENT_BINS = [
   { name: "omo", target: join("components", "ulw-loop", "dist", "cli.js") },
@@ -42,6 +42,23 @@ describe("install-codex", () => {
     expect(repoRoot).toBe(wrapperRoot)
   })
 
+  test("#given wrapper root env #when resolving vendored repo root #then prefers wrapper package root", async () => {
+    // given
+    const platformPackageRoot = await mkdtemp(join(tmpdir(), "omo-codex-platform-package-"))
+    const wrapperRoot = await mkdtemp(join(tmpdir(), "omo-codex-wrapper-package-"))
+    await mkdir(join(wrapperRoot, "packages", "omo-codex", "plugin", ".codex-plugin"), { recursive: true })
+    await writeFile(join(wrapperRoot, "packages", "omo-codex", "plugin", ".codex-plugin", "plugin.json"), "{}")
+
+    // when
+    const repoRoot = findRepoRoot({
+      importerDir: join(platformPackageRoot, "bin"),
+      env: { OMO_WRAPPER_PACKAGE_ROOT: wrapperRoot },
+    })
+
+    // then
+    expect(repoRoot).toBe(wrapperRoot)
+  })
+
   test("#given default CODEX_HOME #when resolving installer bin dir without override #then preserves user local bin precedence", () => {
     // given
     const homeDir = join(tmpdir(), "omo-codex-home-default")
diff --git a/src/cli/install-codex/install-codex.ts b/src/cli/install-codex/install-codex.ts
index 9833c1fae..4ea48ef57 100644
--- a/src/cli/install-codex/install-codex.ts
+++ b/src/cli/install-codex/install-codex.ts
@@ -14,7 +14,7 @@ import type { CodexInstallOptions, CodexInstallResult, CodexMarketplaceSource, I
 const SISYPHUS_LEGACY_CACHE_MARKETPLACES = ["lazycodex", "code-yeongyu-codex-plugins"] as const
 
 export async function runCodexInstaller(options: CodexInstallOptions = {}): Promise<CodexInstallResult> {
-  const repoRoot = resolve(options.repoRoot ?? findRepoRootFromImporter(import.meta.dir))
+  const repoRoot = resolve(options.repoRoot ?? findRepoRoot({ importerDir: import.meta.dir, env: process.env }))
   const codexHome = resolve(options.codexHome ?? process.env.CODEX_HOME ?? join(homedir(), ".codex"))
   const binDir = resolveCodexInstallerBinDir({ binDir: options.binDir, codexHome, env: process.env })
   const runCommand = options.runCommand ?? defaultRunCommand
@@ -199,11 +199,9 @@ function codexMarketplaceSource(marketplaceRoot: string): CodexMarketplaceSource
 export function findRepoRootFromImporter(importerDir: string): string {
   let current = importerDir
   for (let depth = 0; depth <= 5; depth += 1) {
-    const pluginManifestPath = join(current, "packages", "omo-codex", "plugin", ".codex-plugin", "plugin.json")
-    if (existsSyncLike(pluginManifestPath)) return current
+    if (isRepoRootWithCodexPlugin(current)) return current
     for (const wrapperPackageRoot of [join(current, "node_modules", "oh-my-openagent"), join(current, "oh-my-openagent")]) {
-      const wrapperPluginManifestPath = join(wrapperPackageRoot, "packages", "omo-codex", "plugin", ".codex-plugin", "plugin.json")
-      if (existsSyncLike(wrapperPluginManifestPath)) return wrapperPackageRoot
+      if (isRepoRootWithCodexPlugin(wrapperPackageRoot)) return wrapperPackageRoot
     }
     current = resolve(current, "..")
   }
@@ -212,6 +210,22 @@ export function findRepoRootFromImporter(importerDir: string): string {
   )
 }
 
+export function findRepoRoot(input: {
+  readonly importerDir: string
+  readonly env?: { readonly [key: string]: string | undefined }
+}): string {
+  const wrapperPackageRoot = input.env?.OMO_WRAPPER_PACKAGE_ROOT
+  if (wrapperPackageRoot !== undefined && wrapperPackageRoot.trim().length > 0) {
+    const resolvedWrapperPackageRoot = resolve(wrapperPackageRoot)
+    if (isRepoRootWithCodexPlugin(resolvedWrapperPackageRoot)) return resolvedWrapperPackageRoot
+  }
+  return findRepoRootFromImporter(input.importerDir)
+}
+
+function isRepoRootWithCodexPlugin(repoRoot: string): boolean {
+  return existsSyncLike(join(repoRoot, "packages", "omo-codex", "plugin", ".codex-plugin", "plugin.json"))
+}
+
 function existsSyncLike(path: string): boolean {
   return existsSync(path)
 }