diff --git a/apps/client/src/services/llm_chat.ts b/apps/client/src/services/llm_chat.ts
index 2ec00017d4..b2e4efc947 100644
--- a/apps/client/src/services/llm_chat.ts
+++ b/apps/client/src/services/llm_chat.ts
@@ -11,6 +11,8 @@ export interface ChatConfig {
     systemPrompt?: string;
     enableWebSearch?: boolean;
     enableExtendedThinking?: boolean;
+    /** Token budget for extended thinking (default: 10000) */
+    thinkingBudget?: number;
 }
 
 export interface Citation {
diff --git a/apps/server/src/services/llm/providers/anthropic.ts b/apps/server/src/services/llm/providers/anthropic.ts
index c1ba8285d5..545c7b1c9a 100644
--- a/apps/server/src/services/llm/providers/anthropic.ts
+++ b/apps/server/src/services/llm/providers/anthropic.ts
@@ -52,9 +52,12 @@ export class AnthropicProvider implements LlmProvider {
 
             // Enable extended thinking for deeper reasoning
             if (config.enableExtendedThinking) {
+                const thinkingBudget = config.thinkingBudget || 10000;
+                // max_tokens must be greater than thinking budget
+                streamParams.max_tokens = Math.max(streamParams.max_tokens, thinkingBudget + 4000);
                 (streamParams as any).thinking = {
                     type: "enabled",
-                    budget_tokens: 10000 // Allow up to 10k tokens for thinking
+                    budget_tokens: thinkingBudget
                 };
             }
 
diff --git a/apps/server/src/services/llm/types.ts b/apps/server/src/services/llm/types.ts
index 488c53fc1d..d30af7bf90 100644
--- a/apps/server/src/services/llm/types.ts
+++ b/apps/server/src/services/llm/types.ts
@@ -29,6 +29,8 @@ export interface LlmProviderConfig {
     enableWebSearch?: boolean;
     /** Enable extended thinking for deeper reasoning */
     enableExtendedThinking?: boolean;
+    /** Token budget for extended thinking (default: 10000) */
+    thinkingBudget?: number;
 }
 
 export interface LlmProvider {