Clamp minimal reasoning for GPT-5.x

Author: Numman Ali

lib/request/request-transformer.ts

@@ -273,9 +273,9 @@ export function getReasoningConfig(
 		effort = "low";
 	}
 
-	// Normalize "minimal" to "low" for Codex families
-	// Codex CLI presets are low/medium/high (or xhigh for Codex Max / GPT-5.2 Codex)
-	if (isCodex && effort === "minimal") {
+	// Normalize "minimal" to "low" for all non-mini models
+	// The ChatGPT Codex backend does not accept "minimal" (supports none/low/medium/high).
+	if (effort === "minimal") {
 		effort = "low";
 	}
 

test/config.test.ts

@@ -69,10 +69,10 @@ describe('Configuration Parsing', () => {
 			expect(defaultReasoning.summary).toBe('auto');
 		});
 
-		it('should use minimal effort for lightweight models (nano/mini)', () => {
+		it('should normalize lightweight defaults to low effort (nano/mini)', () => {
 			const nanoReasoning = getReasoningConfig('gpt-5-nano', {});
 
-			expect(nanoReasoning.effort).toBe('minimal');
+			expect(nanoReasoning.effort).toBe('low');
 			expect(nanoReasoning.summary).toBe('auto');
 		});
 
@@ -84,11 +84,11 @@ describe('Configuration Parsing', () => {
 			expect(codexMinimalReasoning.summary).toBe('auto');
 		});
 
-		it('should preserve "minimal" effort for non-codex models', () => {
+		it('should normalize "minimal" effort for non-codex models', () => {
 			const gpt5MinimalConfig = { reasoningEffort: 'minimal' as const };
 			const gpt5MinimalReasoning = getReasoningConfig('gpt-5', gpt5MinimalConfig);
 
-			expect(gpt5MinimalReasoning.effort).toBe('minimal');
+			expect(gpt5MinimalReasoning.effort).toBe('low');
 		});
 
 		it('should handle high effort setting', () => {
@@ -134,7 +134,7 @@ describe('Configuration Parsing', () => {
 	describe('Model-specific behavior', () => {
 		it('should detect lightweight models correctly', () => {
 			const miniReasoning = getReasoningConfig('gpt-5-mini', {});
-			expect(miniReasoning.effort).toBe('minimal');
+			expect(miniReasoning.effort).toBe('low');
 		});
 
 		it('should detect codex models correctly', () => {

test/request-transformer.test.ts

@@ -1057,7 +1057,7 @@ describe('Request Transformer Module', () => {
 			expect(result.reasoning?.effort).toBe('low');
 		});
 
-		it('should preserve minimal for non-codex models', async () => {
+		it('should normalize minimal to low for non-codex models', async () => {
 			const body: RequestBody = {
 				model: 'gpt-5',
 				input: [],
@@ -1067,7 +1067,7 @@ describe('Request Transformer Module', () => {
 				models: {},
 			};
 			const result = await transformRequestBody(body, codexInstructions, userConfig);
-			expect(result.reasoning?.effort).toBe('minimal');
+			expect(result.reasoning?.effort).toBe('low');
 		});
 
 		it('should use minimal effort for lightweight models', async () => {
@@ -1079,6 +1079,16 @@ describe('Request Transformer Module', () => {
 			expect(result.reasoning?.effort).toBe('medium');
 		});
 
+		it('should normalize minimal to low when provided by the host', async () => {
+			const body: RequestBody = {
+				model: 'gpt-5-nano',
+				input: [],
+				reasoning: { effort: 'minimal' },
+			};
+			const result = await transformRequestBody(body, codexInstructions);
+			expect(result.reasoning?.effort).toBe('low');
+		});
+
 		it('should convert orphaned function_call_output to message to preserve context', async () => {
 			const body: RequestBody = {
 				model: 'gpt-5-codex',