diff --git a/src/container-runner.ts b/src/container-runner.ts
index 12358a6..622cdf8 100644
--- a/src/container-runner.ts
+++ b/src/container-runner.ts
@@ -202,10 +202,16 @@ function prepareGroupEnvironment(
       process.env.OPENAI_API_KEY;
     if (openaiKey) env.OPENAI_API_KEY = openaiKey;
 
-    // Codex model/effort configuration
-    const codexModel = envVars.CODEX_MODEL || process.env.CODEX_MODEL;
+    // Codex model/effort configuration (per-group overrides global)
+    const codexModel =
+      group.containerConfig?.codexModel ||
+      envVars.CODEX_MODEL ||
+      process.env.CODEX_MODEL;
     if (codexModel) env.CODEX_MODEL = codexModel;
-    const codexEffort = envVars.CODEX_EFFORT || process.env.CODEX_EFFORT;
+    const codexEffort =
+      group.containerConfig?.codexEffort ||
+      envVars.CODEX_EFFORT ||
+      process.env.CODEX_EFFORT;
     if (codexEffort) env.CODEX_EFFORT = codexEffort;
 
     // Codex session directory
@@ -243,7 +249,7 @@ function prepareGroupEnvironment(
         process.env.CLAUDE_CODE_OAUTH_TOKEN ||
         '';
     }
-    // Model/thinking config
+    // Model/thinking config (per-group overrides global)
     for (const key of [
       'CLAUDE_MODEL',
       'CLAUDE_THINKING',
@@ -253,6 +259,12 @@ function prepareGroupEnvironment(
       const val = envVars[key as keyof typeof envVars] || process.env[key];
       if (val) env[key] = val;
     }
+    if (group.containerConfig?.claudeModel) {
+      env.CLAUDE_MODEL = group.containerConfig.claudeModel;
+    }
+    if (group.containerConfig?.claudeEffort) {
+      env.CLAUDE_EFFORT = group.containerConfig.claudeEffort;
+    }
   }
 
   return { env, groupDir, runnerDir };
diff --git a/src/types.ts b/src/types.ts
index 7b0e25e..ebabf32 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -7,6 +7,11 @@ export interface AdditionalMount {
 export interface ContainerConfig {
   additionalMounts?: AdditionalMount[];
   timeout?: number; // Default: 300000 (5 minutes)
+  // Per-group model/effort overrides (take precedence over global env vars)
+  codexModel?: string;
+  codexEffort?: string;
+  claudeModel?: string;
+  claudeEffort?: string;
 }
 
 export type AgentType = 'claude-code' | 'codex';