diff --git a/README.md b/README.md
index c10c260..83f522f 100644
--- a/README.md
+++ b/README.md
@@ -323,10 +323,10 @@ Flynn can run with the built-in native backend or delegate message processing to
 ```yaml
 backends:
   native: { enabled: true }
-  codex: { enabled: false, path: /usr/local/bin/codex }
-  claude_code: { enabled: false, path: /usr/local/bin/claude }
-  opencode: { enabled: false, path: /usr/local/bin/opencode }
-  gemini: { enabled: false, path: /usr/local/bin/gemini }
+  codex: { enabled: false, path: /usr/local/bin/codex, args: [], timeout_ms: 120000 }
+  claude_code: { enabled: false, path: /usr/local/bin/claude, args: [], timeout_ms: 120000 }
+  opencode: { enabled: false, path: /usr/local/bin/opencode, args: [], timeout_ms: 120000 }
+  gemini: { enabled: false, path: /usr/local/bin/gemini, args: [], timeout_ms: 120000 }
 ```
 
 If multiple external backends are enabled, Flynn selects the first in this order: `codex` -> `claude_code` -> `opencode` -> `gemini`.
diff --git a/src/config/schema.test.ts b/src/config/schema.test.ts
index 59b9d5c..e9079c1 100644
--- a/src/config/schema.test.ts
+++ b/src/config/schema.test.ts
@@ -206,9 +206,17 @@ describe('configSchema — backends', () => {
     const result = configSchema.parse(minimalConfig);
     expect(result.backends.native.enabled).toBe(true);
     expect(result.backends.claude_code.enabled).toBe(false);
+    expect(result.backends.claude_code.args).toEqual([]);
+    expect(result.backends.claude_code.timeout_ms).toBe(120000);
     expect(result.backends.opencode.enabled).toBe(false);
+    expect(result.backends.opencode.args).toEqual([]);
+    expect(result.backends.opencode.timeout_ms).toBe(120000);
     expect(result.backends.codex.enabled).toBe(false);
+    expect(result.backends.codex.args).toEqual([]);
+    expect(result.backends.codex.timeout_ms).toBe(120000);
     expect(result.backends.gemini.enabled).toBe(false);
+    expect(result.backends.gemini.args).toEqual([]);
+    expect(result.backends.gemini.timeout_ms).toBe(120000);
   });
 
   it('accepts explicit external backend configs', () => {
@@ -216,15 +224,19 @@ describe('configSchema — backends', () => {
       ...minimalConfig,
       backends: {
         native: { enabled: false },
-        codex: { enabled: true, path: '/usr/local/bin/codex' },
-        gemini: { enabled: true, path: '/usr/local/bin/gemini' },
+        codex: { enabled: true, path: '/usr/local/bin/codex', args: ['run'], timeout_ms: 300000 },
+        gemini: { enabled: true, path: '/usr/local/bin/gemini', args: ['chat'], timeout_ms: 60000 },
       },
     });
     expect(result.backends.native.enabled).toBe(false);
     expect(result.backends.codex.enabled).toBe(true);
     expect(result.backends.codex.path).toBe('/usr/local/bin/codex');
+    expect(result.backends.codex.args).toEqual(['run']);
+    expect(result.backends.codex.timeout_ms).toBe(300000);
     expect(result.backends.gemini.enabled).toBe(true);
     expect(result.backends.gemini.path).toBe('/usr/local/bin/gemini');
+    expect(result.backends.gemini.args).toEqual(['chat']);
+    expect(result.backends.gemini.timeout_ms).toBe(60000);
   });
 });
 
diff --git a/src/daemon/index.test.ts b/src/daemon/index.test.ts
index c545dbb..d33a000 100644
--- a/src/daemon/index.test.ts
+++ b/src/daemon/index.test.ts
@@ -19,7 +19,7 @@ describe('createConfiguredExternalBackend', () => {
       ...base,
       backends: {
         ...base.backends,
-        codex: { enabled: true, path: '/usr/bin/codex' },
+        codex: { enabled: true, path: '/usr/bin/codex', args: [], timeout_ms: 120000 },
       },
     };
     const backend = createConfiguredExternalBackend(cfg);
@@ -31,7 +31,7 @@ describe('createConfiguredExternalBackend', () => {
       ...base,
       backends: {
         ...base.backends,
-        gemini: { enabled: true, path: '/usr/bin/gemini' },
+        gemini: { enabled: true, path: '/usr/bin/gemini', args: [], timeout_ms: 120000 },
       },
     };
     const backend = createConfiguredExternalBackend(cfg);
@@ -43,8 +43,8 @@ describe('createConfiguredExternalBackend', () => {
       ...base,
       backends: {
         ...base.backends,
-        codex: { enabled: true, path: '/usr/bin/codex' },
-        gemini: { enabled: true, path: '/usr/bin/gemini' },
+        codex: { enabled: true, path: '/usr/bin/codex', args: [], timeout_ms: 120000 },
+        gemini: { enabled: true, path: '/usr/bin/gemini', args: [], timeout_ms: 120000 },
       },
     };
     const configured = createConfiguredExternalBackends(cfg);