diff --git a/src/config/index.ts b/src/config/index.ts
index 5ffcf97..2907474 100644
--- a/src/config/index.ts
+++ b/src/config/index.ts
@@ -24,7 +24,7 @@ export function parseLLMConfig(config: LLMConfig): Required<LLMConfig> {
 		baseURL: config.baseURL ?? DEFAULT_BASE_URL,
 		apiKey: config.apiKey ?? DEFAULT_API_KEY,
 		modelName: config.modelName ?? DEFAULT_MODEL_NAME,
-		temperature: config.temperature ?? 0.0,
+		temperature: config.temperature ?? 0.5, // higher randomness helps auto-recovery
 		maxTokens: config.maxTokens ?? 4096,
 		maxRetries: config.maxRetries ?? LLM_MAX_RETRIES,
 	}
diff --git a/src/llms/OpenAIClient.ts b/src/llms/OpenAIClient.ts
index 95df2da..0c4a041 100644
--- a/src/llms/OpenAIClient.ts
+++ b/src/llms/OpenAIClient.ts
@@ -5,6 +5,12 @@ import { InvokeError, InvokeErrorType } from './errors'
 import type { InvokeResult, LLMClient, Message, OpenAIClientConfig, Tool } from './types'
 import { zodToOpenAITool } from './utils'
 
+// Claude's openAI-API has different format for some fields
+const CLAUDE_PATCH = {
+	tool_choice: { type: 'tool', name: 'AgentOutput' },
+	thinking: { type: 'disabled' },
+}
+
 export class OpenAIClient implements LLMClient {
 	config: OpenAIClientConfig
 
@@ -21,7 +27,7 @@ export class OpenAIClient implements LLMClient {
 		const openaiTools = Object.entries(tools).map(([name, tool]) => zodToOpenAITool(name, tool))
 
 		// 2. Detect if Claude (auto-compatibility)
-		// const isClaude = this.config.model.toLowerCase().includes('claude')
+		const isClaude = this.config.model.toLowerCase().startsWith('claude')
 
 		// 3. Call API
 		let response: Response
@@ -34,18 +40,21 @@ export class OpenAIClient implements LLMClient {
 				},
 				body: JSON.stringify({
 					model: this.config.model,
-					messages,
-					parallel_tool_calls: false,
-					tools: openaiTools,
-					tool_choice: 'required',
-					// tool_choice: { type: 'function', function: { name: 'my_function' } },
-					// reasoning_effort: 'minimal',
-					// verbosity: 'low',
-
-					// Claude doesn't support tool_choice: 'required', auto-omit
-					// ...(isClaude ? {} : { tool_choice: 'required' }),
 					temperature: this.config.temperature,
 					max_tokens: this.config.maxTokens,
+					messages,
+
+					tools: openaiTools,
+					// tool_choice: 'required',
+					tool_choice: { type: 'function', function: { name: 'AgentOutput' } },
+
+					// model specific params
+
+					// reasoning_effort: 'minimal',
+					// verbosity: 'low',
+					parallel_tool_calls: false,
+
+					...(isClaude ? CLAUDE_PATCH : {}),
 				}),
 				signal: abortSignal,
 			})