update xml output parser

packages/components/src/agents.ts

@@ -779,3 +779,36 @@ Final Answer: the final answer to the original input question`
         })
     }
 }
+
+export class XMLAgentOutputParser extends AgentActionOutputParser {
+    lc_namespace = ['langchain', 'agents', 'xml']
+
+    static lc_name() {
+        return 'XMLAgentOutputParser'
+    }
+
+    /**
+     * Parses the output text from the agent and returns an AgentAction or
+     * AgentFinish object.
+     * @param text The output text from the agent.
+     * @returns An AgentAction or AgentFinish object.
+     */
+    async parse(text: string): Promise<AgentAction | AgentFinish> {
+        if (text.includes('</tool>')) {
+            const [tool, toolInput] = text.split('</tool>')
+            const _tool = tool.split('<tool>')[1]
+            const _toolInput = toolInput.split('<tool_input>')[1]
+            return { tool: _tool, toolInput: _toolInput, log: text }
+        } else if (text.includes('<final_answer>')) {
+            const [, answer] = text.split('<final_answer>')
+            return { returnValues: { output: answer }, log: text }
+        } else {
+            // Instead of throwing Error, we return a AgentFinish object
+            return { returnValues: { output: text }, log: text }
+        }
+    }
+
+    getFormatInstructions(): string {
+        throw new Error('getFormatInstructions not implemented inside XMLAgentOutputParser.')
+    }
+}