diff --git a/src/targets/codex-adapter.ts b/src/targets/codex-adapter.ts
index b2e6f774..d4491288 100644
--- a/src/targets/codex-adapter.ts
+++ b/src/targets/codex-adapter.ts
@@ -14,6 +14,7 @@ import {
   codexBinarySupportsConfigOverrides,
   detectCodexCli,
   getCodexBinaryInfo,
+  readCodexVersion,
 } from './codex-detector';
 
 const CODEX_RUNTIME_PROVIDER_ID = 'ccs_runtime';
@@ -35,6 +36,17 @@ function buildConfigOverrideSupportError(binaryInfo?: TargetBinaryInfo): Error {
   );
 }
 
+function hydrateCodexBinaryVersion(binaryInfo?: TargetBinaryInfo): TargetBinaryInfo | undefined {
+  if (!binaryInfo || binaryInfo.version || !binaryInfo.path) {
+    return binaryInfo;
+  }
+
+  return {
+    ...binaryInfo,
+    version: readCodexVersion(binaryInfo.path),
+  };
+}
+
 function findDisallowedCodexManagedFlags(args: string[]): string[] {
   const disallowed = new Set<string>();
 
@@ -99,7 +111,7 @@ export class CodexAdapter implements TargetAdapter {
     if (profileType === 'default') {
       if (reasoningOverride) {
         if (!codexBinarySupportsConfigOverrides(options?.binaryInfo)) {
-          throw buildConfigOverrideSupportError(options?.binaryInfo);
+          throw buildConfigOverrideSupportError(hydrateCodexBinaryVersion(options?.binaryInfo));
         }
         return [
           ...buildConfigOverrideArgs([
@@ -112,7 +124,7 @@ export class CodexAdapter implements TargetAdapter {
     }
 
     if (!codexBinarySupportsConfigOverrides(options?.binaryInfo)) {
-      throw buildConfigOverrideSupportError(options?.binaryInfo);
+      throw buildConfigOverrideSupportError(hydrateCodexBinaryVersion(options?.binaryInfo));
     }
 
     if (!creds?.baseUrl?.trim() || !creds.apiKey?.trim()) {
diff --git a/src/targets/codex-detector.ts b/src/targets/codex-detector.ts
index 56cfb79b..faf52a35 100644
--- a/src/targets/codex-detector.ts
+++ b/src/targets/codex-detector.ts
@@ -45,7 +45,7 @@ function runCodexProbe(codexPath: string, args: string[]): string | undefined {
   }
 }
 
-function readCodexVersion(codexPath: string): string | undefined {
+export function readCodexVersion(codexPath: string): string | undefined {
   return runCodexProbe(codexPath, ['--version'])?.trim();
 }
 
diff --git a/tests/unit/targets/codex-runtime-integration.test.ts b/tests/unit/targets/codex-runtime-integration.test.ts
index 50c2000c..161348fd 100644
--- a/tests/unit/targets/codex-runtime-integration.test.ts
+++ b/tests/unit/targets/codex-runtime-integration.test.ts
@@ -53,11 +53,25 @@ function readLoggedCodexCalls(logPath: string): string[][] {
     .map((line) => JSON.parse(line) as string[]);
 }
 
+function readLoggedCodexEnv(logPath: string): Record<string, string | undefined>[] {
+  if (!fs.existsSync(logPath)) {
+    return [];
+  }
+
+  return fs
+    .readFileSync(logPath, 'utf8')
+    .trim()
+    .split('\n')
+    .filter(Boolean)
+    .map((line) => JSON.parse(line) as Record<string, string | undefined>);
+}
+
 describe('codex runtime integration', () => {
   let tmpHome: string;
   let ccsDir: string;
   let fakeCodexPath: string;
   let codexArgsLogPath: string;
+  let codexEnvLogPath: string;
   let emptyPathDir: string;
 
   beforeEach(() => {
@@ -69,6 +83,7 @@ describe('codex runtime integration', () => {
     ccsDir = path.join(tmpHome, '.ccs');
     fakeCodexPath = path.join(tmpHome, 'fake-codex.js');
     codexArgsLogPath = path.join(tmpHome, 'codex-args.log');
+    codexEnvLogPath = path.join(tmpHome, 'codex-env.log');
     emptyPathDir = path.join(tmpHome, 'empty-bin');
 
     fs.mkdirSync(ccsDir, { recursive: true });
@@ -82,6 +97,19 @@ const out = process.env.CCS_TEST_CODEX_ARGS_OUT;
 if (out) {
   fs.appendFileSync(out, JSON.stringify(process.argv.slice(2)) + '\\n');
 }
+const envOut = process.env.CCS_TEST_CODEX_ENV_OUT;
+if (envOut) {
+  fs.appendFileSync(
+    envOut,
+    JSON.stringify({
+      CODEX_HOME: process.env.CODEX_HOME,
+      CODEX_CI: process.env.CODEX_CI,
+      CODEX_MANAGED_BY_BUN: process.env.CODEX_MANAGED_BY_BUN,
+      CODEX_THREAD_ID: process.env.CODEX_THREAD_ID,
+      ANTHROPIC_BASE_URL: process.env.ANTHROPIC_BASE_URL,
+    }) + '\\n'
+  );
+}
 if (process.argv[2] === '--version' || process.argv[2] === '-v') {
   process.stdout.write(process.env.CCS_TEST_CODEX_VERSION || 'codex-cli 0.118.0-alpha.3');
   process.exit(0);
@@ -184,6 +212,38 @@ process.exit(0);
     });
   }
 
+  it('strips nested Codex session env from passthrough launches while keeping CODEX_HOME', () => {
+    if (process.platform === 'win32') return;
+
+    const result = runCodexAlias(['--version'], {
+      ...process.env,
+      CI: '1',
+      NO_COLOR: '1',
+      CCS_HOME: tmpHome,
+      CCS_CODEX_PATH: fakeCodexPath,
+      CCS_TEST_CODEX_ARGS_OUT: codexArgsLogPath,
+      CCS_TEST_CODEX_ENV_OUT: codexEnvLogPath,
+      CCS_TEST_CODEX_VERSION: 'codex-cli 9.9.9-test',
+      CODEX_HOME: '/tmp/codex-home',
+      CODEX_CI: '1',
+      CODEX_MANAGED_BY_BUN: '1',
+      CODEX_THREAD_ID: 'thread-123',
+      ANTHROPIC_BASE_URL: 'https://stale-proxy.invalid',
+    });
+
+    expect(result.status).toBe(0);
+    expect(readLoggedCodexCalls(codexArgsLogPath)).toEqual([['--version']]);
+    expect(readLoggedCodexEnv(codexEnvLogPath)).toEqual([
+      {
+        CODEX_HOME: '/tmp/codex-home',
+        CODEX_CI: undefined,
+        CODEX_MANAGED_BY_BUN: undefined,
+        CODEX_THREAD_ID: undefined,
+        ANTHROPIC_BASE_URL: undefined,
+      },
+    ]);
+  });
+
   it('fails fast when native Codex reasoning overrides need unsupported --config support', () => {
     if (process.platform === 'win32') return;
 
@@ -194,13 +254,15 @@ process.exit(0);
       CCS_HOME: tmpHome,
       CCS_CODEX_PATH: fakeCodexPath,
       CCS_TEST_CODEX_ARGS_OUT: codexArgsLogPath,
+      CCS_TEST_CODEX_VERSION: 'codex-cli 9.9.9-test',
       CCS_TEST_CODEX_HELP: '  -p, --profile <CONFIG_PROFILE>\\n',
     });
 
     expect(result.status).toBe(1);
+    expect(result.stderr).toContain('Codex CLI (codex-cli 9.9.9-test)');
     expect(result.stderr).toContain('does not advertise --config overrides');
     const calls = readLoggedCodexCalls(codexArgsLogPath);
-    expect(calls).toEqual([['--help']]);
+    expect(calls).toEqual([['--help'], ['--version']]);
   });
 
   it('reports unsupported generic settings profiles before Codex install guidance', () => {