feat: add gpt-5 support (#1105)

* feat: add gpt-5 support

.changeset/vast-weeks-fetch.md

@@ -0,0 +1,7 @@
+---
+"task-master-ai": minor
+---
+
+Add GPT-5 support with proper parameter handling
+
+- Added GPT-5 model to supported models configuration with SWE score of 0.749

CLAUDE.md

@@ -3,3 +3,7 @@
 ## Task Master AI Instructions
 **Import Task Master's development workflow commands and guidelines, treat as if import is in the main CLAUDE.md file.**
 @./.taskmaster/CLAUDE.md
+
+## Changeset Guidelines
+
+- When creating changesets, remember that it's user-facing, meaning we don't have to get into the specifics of the code, but rather mention what the end-user is getting or fixing from this changeset.

scripts/modules/config-manager.js

@@ -557,6 +557,7 @@ function getParametersForRole(role, explicitRoot = null) {
 	const providerName = roleConfig.provider;
 
 	let effectiveMaxTokens = roleMaxTokens; // Start with the role's default
+	let effectiveTemperature = roleTemperature; // Start with the role's default
 
 	try {
 		// Find the model definition in MODEL_MAP
@@ -583,6 +584,20 @@ function getParametersForRole(role, explicitRoot = null) {
 					`No valid model-specific max_tokens override found for ${modelId}. Using role default: ${roleMaxTokens}`
 				);
 			}
+
+			// Check if a model-specific temperature is defined
+			if (
+				modelDefinition &&
+				typeof modelDefinition.temperature === 'number' &&
+				modelDefinition.temperature >= 0 &&
+				modelDefinition.temperature <= 1
+			) {
+				effectiveTemperature = modelDefinition.temperature;
+				log(
+					'debug',
+					`Applying model-specific temperature (${modelDefinition.temperature}) for ${modelId}`
+				);
+			}
 		} else {
 			// Special handling for custom OpenRouter models
 			if (providerName === CUSTOM_PROVIDERS.OPENROUTER) {
@@ -603,15 +618,16 @@ function getParametersForRole(role, explicitRoot = null) {
 	} catch (lookupError) {
 		log(
 			'warn',
-			`Error looking up model-specific max_tokens for ${modelId}: ${lookupError.message}. Using role default: ${roleMaxTokens}`
+			`Error looking up model-specific parameters for ${modelId}: ${lookupError.message}. Using role defaults.`
 		);
-		// Fallback to role default on error
+		// Fallback to role defaults on error
 		effectiveMaxTokens = roleMaxTokens;
+		effectiveTemperature = roleTemperature;
 	}
 
 	return {
 		maxTokens: effectiveMaxTokens,
-		temperature: roleTemperature
+		temperature: effectiveTemperature
 	};
 }
 

scripts/modules/supported-models.json

@@ -239,6 +239,18 @@
 			},
 			"allowed_roles": ["research"],
 			"supported": true
+		},
+		{
+			"id": "gpt-5",
+			"swe_score": 0.749,
+			"cost_per_1m_tokens": {
+				"input": 5.0,
+				"output": 20.0
+			},
+			"allowed_roles": ["main", "fallback"],
+			"max_tokens": 100000,
+			"temperature": 1,
+			"supported": true
 		}
 	],
 	"google": [

src/ai-providers/base-provider.js

@@ -61,8 +61,11 @@ export class BaseAIProvider {
 		) {
 			throw new Error('Temperature must be between 0 and 1');
 		}
-		if (params.maxTokens !== undefined && params.maxTokens <= 0) {
-			throw new Error('maxTokens must be greater than 0');
+		if (params.maxTokens !== undefined) {
+			const maxTokens = Number(params.maxTokens);
+			if (!Number.isFinite(maxTokens) || maxTokens <= 0) {
+				throw new Error('maxTokens must be a finite number greater than 0');
+			}
 		}
 	}
 
@@ -122,6 +125,37 @@ export class BaseAIProvider {
 		throw new Error('getRequiredApiKeyName must be implemented by provider');
 	}
 
+	/**
+	 * Determines if a model requires max_completion_tokens instead of maxTokens
+	 * Can be overridden by providers to specify their model requirements
+	 * @param {string} modelId - The model ID to check
+	 * @returns {boolean} True if the model requires max_completion_tokens
+	 */
+	requiresMaxCompletionTokens(modelId) {
+		return false; // Default behavior - most models use maxTokens
+	}
+
+	/**
+	 * Prepares token limit parameter based on model requirements
+	 * @param {string} modelId - The model ID
+	 * @param {number} maxTokens - The maximum tokens value
+	 * @returns {object} Object with either maxTokens or max_completion_tokens
+	 */
+	prepareTokenParam(modelId, maxTokens) {
+		if (maxTokens === undefined) {
+			return {};
+		}
+
+		// Ensure maxTokens is an integer
+		const tokenValue = Math.floor(Number(maxTokens));
+
+		if (this.requiresMaxCompletionTokens(modelId)) {
+			return { max_completion_tokens: tokenValue };
+		} else {
+			return { maxTokens: tokenValue };
+		}
+	}
+
 	/**
 	 * Generates text using the provider's model
 	 */
@@ -139,7 +173,7 @@ export class BaseAIProvider {
 			const result = await generateText({
 				model: client(params.modelId),
 				messages: params.messages,
-				maxTokens: params.maxTokens,
+				...this.prepareTokenParam(params.modelId, params.maxTokens),
 				temperature: params.temperature
 			});
 
@@ -175,7 +209,7 @@ export class BaseAIProvider {
 			const stream = await streamText({
 				model: client(params.modelId),
 				messages: params.messages,
-				maxTokens: params.maxTokens,
+				...this.prepareTokenParam(params.modelId, params.maxTokens),
 				temperature: params.temperature
 			});
 
@@ -216,7 +250,7 @@ export class BaseAIProvider {
 				messages: params.messages,
 				schema: zodSchema(params.schema),
 				mode: params.mode || 'auto',
-				maxTokens: params.maxTokens,
+				...this.prepareTokenParam(params.modelId, params.maxTokens),
 				temperature: params.temperature
 			});
 

src/ai-providers/openai.js

@@ -20,6 +20,16 @@ export class OpenAIProvider extends BaseAIProvider {
 		return 'OPENAI_API_KEY';
 	}
 
+	/**
+	 * Determines if a model requires max_completion_tokens instead of maxTokens
+	 * GPT-5 models require max_completion_tokens parameter
+	 * @param {string} modelId - The model ID to check
+	 * @returns {boolean} True if the model requires max_completion_tokens
+	 */
+	requiresMaxCompletionTokens(modelId) {
+		return modelId && modelId.startsWith('gpt-5');
+	}
+
 	/**
 	 * Creates and returns an OpenAI client instance.
 	 * @param {object} params - Parameters for client initialization

tests/unit/ai-providers/openai.test.js

@@ -0,0 +1,238 @@
+/**
+ * Tests for OpenAI Provider - Token parameter handling for GPT-5
+ *
+ * This test suite covers:
+ * 1. Correct identification of GPT-5 models requiring max_completion_tokens
+ * 2. Token parameter preparation for different model types
+ * 3. Validation of maxTokens parameter
+ * 4. Integer coercion of token values
+ */
+
+import { jest } from '@jest/globals';
+
+// Mock the utils module to prevent logging during tests
+jest.mock('../../../scripts/modules/utils.js', () => ({
+	log: jest.fn()
+}));
+
+// Import the provider
+import { OpenAIProvider } from '../../../src/ai-providers/openai.js';
+
+describe('OpenAIProvider', () => {
+	let provider;
+
+	beforeEach(() => {
+		provider = new OpenAIProvider();
+		jest.clearAllMocks();
+	});
+
+	describe('requiresMaxCompletionTokens', () => {
+		it('should return true for GPT-5 models', () => {
+			expect(provider.requiresMaxCompletionTokens('gpt-5')).toBe(true);
+			expect(provider.requiresMaxCompletionTokens('gpt-5-mini')).toBe(true);
+			expect(provider.requiresMaxCompletionTokens('gpt-5-nano')).toBe(true);
+			expect(provider.requiresMaxCompletionTokens('gpt-5-turbo')).toBe(true);
+		});
+
+		it('should return false for non-GPT-5 models', () => {
+			expect(provider.requiresMaxCompletionTokens('gpt-4')).toBe(false);
+			expect(provider.requiresMaxCompletionTokens('gpt-4o')).toBe(false);
+			expect(provider.requiresMaxCompletionTokens('gpt-3.5-turbo')).toBe(false);
+			expect(provider.requiresMaxCompletionTokens('o1')).toBe(false);
+			expect(provider.requiresMaxCompletionTokens('o1-mini')).toBe(false);
+		});
+
+		it('should handle null/undefined modelId', () => {
+			expect(provider.requiresMaxCompletionTokens(null)).toBeFalsy();
+			expect(provider.requiresMaxCompletionTokens(undefined)).toBeFalsy();
+			expect(provider.requiresMaxCompletionTokens('')).toBeFalsy();
+		});
+	});
+
+	describe('prepareTokenParam', () => {
+		it('should return max_completion_tokens for GPT-5 models', () => {
+			const result = provider.prepareTokenParam('gpt-5', 1000);
+			expect(result).toEqual({ max_completion_tokens: 1000 });
+		});
+
+		it('should return maxTokens for non-GPT-5 models', () => {
+			const result = provider.prepareTokenParam('gpt-4', 1000);
+			expect(result).toEqual({ maxTokens: 1000 });
+		});
+
+		it('should coerce token value to integer', () => {
+			// Float values
+			const result1 = provider.prepareTokenParam('gpt-5', 1000.7);
+			expect(result1).toEqual({ max_completion_tokens: 1000 });
+
+			const result2 = provider.prepareTokenParam('gpt-4', 1000.7);
+			expect(result2).toEqual({ maxTokens: 1000 });
+
+			// String float
+			const result3 = provider.prepareTokenParam('gpt-5', '1000.7');
+			expect(result3).toEqual({ max_completion_tokens: 1000 });
+
+			// String integers (common CLI input path)
+			expect(provider.prepareTokenParam('gpt-5', '1000')).toEqual({
+				max_completion_tokens: 1000
+			});
+			expect(provider.prepareTokenParam('gpt-4', '1000')).toEqual({
+				maxTokens: 1000
+			});
+		});
+
+		it('should return empty object for undefined maxTokens', () => {
+			const result = provider.prepareTokenParam('gpt-5', undefined);
+			expect(result).toEqual({});
+		});
+
+		it('should handle edge cases', () => {
+			// Test with 0 (should still pass through as 0)
+			const result1 = provider.prepareTokenParam('gpt-5', 0);
+			expect(result1).toEqual({ max_completion_tokens: 0 });
+
+			// Test with string number
+			const result2 = provider.prepareTokenParam('gpt-5', '100');
+			expect(result2).toEqual({ max_completion_tokens: 100 });
+
+			// Test with negative number (will be floored, validation happens elsewhere)
+			const result3 = provider.prepareTokenParam('gpt-4', -10.5);
+			expect(result3).toEqual({ maxTokens: -11 });
+		});
+	});
+
+	describe('validateOptionalParams', () => {
+		it('should accept valid maxTokens values', () => {
+			expect(() =>
+				provider.validateOptionalParams({ maxTokens: 1000 })
+			).not.toThrow();
+			expect(() =>
+				provider.validateOptionalParams({ maxTokens: 1 })
+			).not.toThrow();
+			expect(() =>
+				provider.validateOptionalParams({ maxTokens: '1000' })
+			).not.toThrow();
+		});
+
+		it('should reject invalid maxTokens values', () => {
+			expect(() => provider.validateOptionalParams({ maxTokens: 0 })).toThrow(
+				Error
+			);
+			expect(() => provider.validateOptionalParams({ maxTokens: -1 })).toThrow(
+				Error
+			);
+			expect(() => provider.validateOptionalParams({ maxTokens: NaN })).toThrow(
+				Error
+			);
+			expect(() =>
+				provider.validateOptionalParams({ maxTokens: Infinity })
+			).toThrow(Error);
+			expect(() =>
+				provider.validateOptionalParams({ maxTokens: 'invalid' })
+			).toThrow(Error);
+		});
+
+		it('should accept valid temperature values', () => {
+			expect(() =>
+				provider.validateOptionalParams({ temperature: 0 })
+			).not.toThrow();
+			expect(() =>
+				provider.validateOptionalParams({ temperature: 0.5 })
+			).not.toThrow();
+			expect(() =>
+				provider.validateOptionalParams({ temperature: 1 })
+			).not.toThrow();
+		});
+
+		it('should reject invalid temperature values', () => {
+			expect(() =>
+				provider.validateOptionalParams({ temperature: -0.1 })
+			).toThrow(Error);
+			expect(() =>
+				provider.validateOptionalParams({ temperature: 1.1 })
+			).toThrow(Error);
+		});
+	});
+
+	describe('getRequiredApiKeyName', () => {
+		it('should return OPENAI_API_KEY', () => {
+			expect(provider.getRequiredApiKeyName()).toBe('OPENAI_API_KEY');
+		});
+	});
+
+	describe('getClient', () => {
+		it('should throw error if API key is missing', () => {
+			expect(() => provider.getClient({})).toThrow(Error);
+		});
+
+		it('should create client with apiKey only', () => {
+			const params = {
+				apiKey: 'sk-test-123'
+			};
+
+			// The getClient method should return a function
+			const client = provider.getClient(params);
+			expect(typeof client).toBe('function');
+
+			// The client function should be callable and return a model object
+			const model = client('gpt-4');
+			expect(model).toBeDefined();
+			expect(model.modelId).toBe('gpt-4');
+		});
+
+		it('should create client with apiKey and baseURL', () => {
+			const params = {
+				apiKey: 'sk-test-456',
+				baseURL: 'https://api.openai.example'
+			};
+
+			// Should not throw when baseURL is provided
+			const client = provider.getClient(params);
+			expect(typeof client).toBe('function');
+
+			// The client function should be callable and return a model object
+			const model = client('gpt-5');
+			expect(model).toBeDefined();
+			expect(model.modelId).toBe('gpt-5');
+		});
+
+		it('should return the same client instance for the same parameters', () => {
+			const params = {
+				apiKey: 'sk-test-789'
+			};
+
+			// Multiple calls with same params should work
+			const client1 = provider.getClient(params);
+			const client2 = provider.getClient(params);
+
+			expect(typeof client1).toBe('function');
+			expect(typeof client2).toBe('function');
+
+			// Both clients should be able to create models
+			const model1 = client1('gpt-4');
+			const model2 = client2('gpt-4');
+			expect(model1.modelId).toBe('gpt-4');
+			expect(model2.modelId).toBe('gpt-4');
+		});
+
+		it('should handle different model IDs correctly', () => {
+			const client = provider.getClient({ apiKey: 'sk-test-models' });
+
+			// Test with different models
+			const gpt4 = client('gpt-4');
+			expect(gpt4.modelId).toBe('gpt-4');
+
+			const gpt5 = client('gpt-5');
+			expect(gpt5.modelId).toBe('gpt-5');
+
+			const gpt35 = client('gpt-3.5-turbo');
+			expect(gpt35.modelId).toBe('gpt-3.5-turbo');
+		});
+	});
+
+	describe('name property', () => {
+		it('should have OpenAI as the provider name', () => {
+			expect(provider.name).toBe('OpenAI');
+		});
+	});
+});