refactor(agent): changed regex for tool use extraction to look for optional "Input:" prefix to comply with Cohere command-r models (#1654)

.changeset/sweet-llamas-dress.md

@@ -0,0 +1,5 @@
+---
+"llamaindex": patch
+---
+
+fix: Update react agent to support tool calls from Cohere command-r models

packages/llamaindex/src/agent/react.ts

@@ -100,7 +100,7 @@ function extractToolUse(
   inputText: string,
 ): [thought: string, action: string, input: string] {
   const pattern =
-    /\s*Thought: (.*?)\nAction: ([a-zA-Z0-9_]+).*?\.*Input: .*?(\{.*?\})/s;
+    /\s*Thought: (.*?)\nAction: ([a-zA-Z0-9_]+).*?\.*[Input:]*.*?(\{.*?\})/s;
 
   const match = inputText.match(pattern);