diff --git a/src/cliproxy/cliproxy-executor.ts b/src/cliproxy/cliproxy-executor.ts
index 03c8c04f..ecaaff24 100644
--- a/src/cliproxy/cliproxy-executor.ts
+++ b/src/cliproxy/cliproxy-executor.ts
@@ -27,6 +27,7 @@ import {
   CLIPROXY_DEFAULT_PORT,
   getCliproxyWritablePath,
   validatePort,
+  applyThinkingConfig,
 } from './config-generator';
 import { checkRemoteProxy } from './remote-proxy-client';
 import { isAuthenticated } from './auth-handler';
@@ -311,6 +312,21 @@ export async function execClaudeWithCLIProxy(
     setNickname = argsWithoutProxy[nicknameIdx + 1];
   }
 
+  // Parse --thinking <value> flag for thinking budget control
+  // Supports: level names (low, medium, high, xhigh, auto), numeric budget, or 'off'/'none'
+  let thinkingOverride: string | number | undefined;
+  const thinkingIdx = argsWithoutProxy.indexOf('--thinking');
+  if (
+    thinkingIdx !== -1 &&
+    argsWithoutProxy[thinkingIdx + 1] &&
+    !argsWithoutProxy[thinkingIdx + 1].startsWith('-')
+  ) {
+    const val = argsWithoutProxy[thinkingIdx + 1];
+    // Parse as number if numeric, otherwise keep as string (level name)
+    const numVal = parseInt(val, 10);
+    thinkingOverride = !isNaN(numVal) ? numVal : val;
+  }
+
   // Handle --accounts: list accounts and exit
   if (showAccounts) {
     const accounts = getProviderAccounts(provider);
@@ -704,6 +720,10 @@ export async function execClaudeWithCLIProxy(
       )
     : getEffectiveEnvVars(provider, cfg.port, cfg.customSettingsPath, remoteRewriteConfig);
 
+  // Apply thinking configuration to model (auto tier-based or manual override)
+  // This adds thinking suffix like model(high) or model(8192) for CLIProxyAPIPlus
+  applyThinkingConfig(envVars, provider, thinkingOverride);
+
   // Codex-only: inject OpenAI reasoning effort based on tier model mapping.
   // Maps by request.model:
   // - OPUS/default model → xhigh
@@ -789,6 +809,7 @@ export async function execClaudeWithCLIProxy(
     '--accounts',
     '--use',
     '--nickname',
+    '--thinking',
     '--incognito',
     '--no-incognito',
     '--import',
@@ -798,8 +819,12 @@ export async function execClaudeWithCLIProxy(
   const claudeArgs = argsWithoutProxy.filter((arg, idx) => {
     // Filter out CCS flags
     if (ccsFlags.includes(arg)) return false;
-    // Filter out value after --use or --nickname
-    if (argsWithoutProxy[idx - 1] === '--use' || argsWithoutProxy[idx - 1] === '--nickname')
+    // Filter out value after --use, --nickname, or --thinking
+    if (
+      argsWithoutProxy[idx - 1] === '--use' ||
+      argsWithoutProxy[idx - 1] === '--nickname' ||
+      argsWithoutProxy[idx - 1] === '--thinking'
+    )
       return false;
     return true;
   });
diff --git a/src/commands/help-command.ts b/src/commands/help-command.ts
index b443b5f2..42de0433 100644
--- a/src/commands/help-command.ts
+++ b/src/commands/help-command.ts
@@ -172,6 +172,10 @@ Run ${color('ccs config', 'command')} for web dashboard`.trim();
       ['ccs <provider> --accounts', 'List all accounts'],
       ['ccs <provider> --use <name>', 'Switch to account'],
       ['ccs <provider> --config', 'Change model (agy, gemini)'],
+      [
+        'ccs <provider> --thinking <value>',
+        'Set thinking budget (low/medium/high/xhigh/auto/off or number)',
+      ],
       ['ccs <provider> --logout', 'Clear authentication'],
       ['ccs <provider> --headless', 'Headless auth (for SSH)'],
       ['ccs kiro --import', 'Import token from Kiro IDE'],