feat: add codex reasoning effort option (#297)

cli/src/api/apiMachine.ts

@@ -102,7 +102,7 @@ export class ApiMachineClient {
 
     setRPCHandlers({ spawnSession, stopSession, requestShutdown }: MachineRpcHandlers): void {
         this.rpcHandlerManager.registerHandler('spawn-happy-session', async (params: any) => {
-            const { directory, sessionId, resumeSessionId, machineId, approvedNewDirectoryCreation, agent, model, yolo, token, sessionType, worktreeName } = params || {}
+            const { directory, sessionId, resumeSessionId, machineId, approvedNewDirectoryCreation, agent, model, modelReasoningEffort, yolo, token, sessionType, worktreeName } = params || {}
 
             if (!directory) {
                 throw new Error('Directory is required')
@@ -116,6 +116,7 @@ export class ApiMachineClient {
                 approvedNewDirectoryCreation,
                 agent,
                 model,
+                modelReasoningEffort,
                 yolo,
                 token,
                 sessionType,

cli/src/codex/loop.ts

@@ -14,6 +14,7 @@ export interface EnhancedMode {
     permissionMode: PermissionMode;
     model?: string;
     collaborationMode: CodexCollaborationMode;
+    modelReasoningEffort?: string;
 }
 
 interface LoopOptions {

cli/src/codex/runCodex.ts

@@ -21,6 +21,7 @@ export async function runCodex(opts: {
     permissionMode?: PermissionMode;
     resumeSessionId?: string;
     model?: string;
+    modelReasoningEffort?: string;
 }): Promise<void> {
     const workingDirectory = getInvokedCwd();
     const startedBy = opts.startedBy ?? 'terminal';
@@ -45,6 +46,7 @@ export async function runCodex(opts: {
     const messageQueue = new MessageQueue2<EnhancedMode>((mode) => hashObject({
         permissionMode: mode.permissionMode,
         model: mode.model,
+        modelReasoningEffort: mode.modelReasoningEffort,
         collaborationMode: mode.collaborationMode
     }));
 
@@ -53,6 +55,7 @@ export async function runCodex(opts: {
 
     let currentPermissionMode: PermissionMode = opts.permissionMode ?? 'default';
     let currentModel = opts.model;
+    const currentModelReasoningEffort = opts.modelReasoningEffort;
     let currentCollaborationMode: EnhancedMode['collaborationMode'] = 'default';
 
     const lifecycle = createRunnerLifecycle({
@@ -105,6 +108,7 @@ export async function runCodex(opts: {
         const enhancedMode: EnhancedMode = {
             permissionMode: messagePermissionMode ?? 'default',
             model: currentModel,
+            modelReasoningEffort: currentModelReasoningEffort,
             collaborationMode: currentCollaborationMode
         };
         const formattedText = formatMessageWithAttachments(message.content.text, message.content.attachments);

cli/src/codex/utils/appServerConfig.test.ts

@@ -64,6 +64,22 @@ describe('appServerConfig', () => {
         });
     });
 
+    it('passes model reasoning effort via thread config', () => {
+        const params = buildThreadStartParams({
+            mode: { permissionMode: 'default', modelReasoningEffort: 'xhigh', collaborationMode: 'default' },
+            mcpServers
+        });
+
+        expect(params.config).toEqual({
+            'mcp_servers.hapi': {
+                command: 'node',
+                args: ['mcp']
+            },
+            developer_instructions: codexSystemPrompt,
+            model_reasoning_effort: 'xhigh'
+        });
+    });
+
     it('builds turn params with mode defaults', () => {
         const params = buildTurnStartParams({
             threadId: 'thread-1',

cli/src/codex/utils/appServerConfig.ts

@@ -84,7 +84,8 @@ export function buildThreadStartParams(args: {
     } = resolveInstructions(args);
     const configWithInstructions = {
         ...config,
-        developer_instructions: resolvedDeveloperInstructions
+        developer_instructions: resolvedDeveloperInstructions,
+        ...(args.mode.modelReasoningEffort ? { model_reasoning_effort: args.mode.modelReasoningEffort } : {})
     };
 
     const params: ThreadStartParams = {

cli/src/commands/codex.ts

@@ -18,6 +18,7 @@ export const codexCommand: CommandDefinition = {
                 permissionMode?: CodexPermissionMode
                 resumeSessionId?: string
                 model?: string
+                modelReasoningEffort?: string
             } = {}
             const unknownArgs: string[] = []
 
@@ -44,6 +45,12 @@ export const codexCommand: CommandDefinition = {
                     }
                     options.model = model
                     unknownArgs.push('--model', model)
+                } else if (arg === '--model-reasoning-effort') {
+                    const effort = commandArgs[++i]
+                    if (!effort) {
+                        throw new Error('Missing --model-reasoning-effort value')
+                    }
+                    options.modelReasoningEffort = effort
                 } else {
                     unknownArgs.push(arg)
                 }

cli/src/modules/common/rpcTypes.ts

@@ -6,6 +6,7 @@ export interface SpawnSessionOptions {
     approvedNewDirectoryCreation?: boolean
     agent?: 'claude' | 'codex' | 'cursor' | 'gemini' | 'opencode'
     model?: string
+    modelReasoningEffort?: string
     yolo?: boolean
     token?: string
     sessionType?: 'simple' | 'worktree'

cli/src/runner/run.ts

@@ -361,6 +361,9 @@ export async function startRunner(): Promise<void> {
         if (options.model && agent !== 'opencode') {
           args.push('--model', options.model);
         }
+        if (options.modelReasoningEffort && agent === 'codex') {
+          args.push('--model-reasoning-effort', options.modelReasoningEffort);
+        }
         if (yolo) {
           args.push('--yolo');
         }