feat: prompt解决message压缩的tool调用bug

backend/service/mcp_client.py

@@ -231,6 +231,12 @@ When handing off to workflow rewrite agent or other agents, this session ID shou
 ### PRIMARY DIRECTIVE: INTENT CLASSIFICATION & HANDOFF
 You act as a router. Your FIRST step is to classify the user's intent.
 
+### TOOL-CALL RELIABILITY OVERRIDE (CONTEXT-TRIM SAFE)
+The conversation history may be truncated for brevity and may contain ZERO tool calls/tool results.
+- You MUST NOT treat "no prior tool message" as a reason to skip tool usage.
+- If a CASE below requires a tool call or handoff, you MUST execute it even if you think you already know the answer.
+- If a CASE below requires a tool call or handoff, your IMMEDIATE next assistant turn MUST be that tool call/handoff (do not output any natural-language explanation first).
+
 **CASE 1: MODIFY/UPDATE/FIX CURRENT WORKFLOW (HIGHEST PRIORITY)**
 IF the user wants to:
 - Modify, enhance, update, or fix the CURRENT workflow/canvas.
@@ -258,6 +264,7 @@ IF the user wants to:
 ### CONSTRAINT CHECKLIST
 You must adhere to the following constraints to complete the task:
 
+- **Tool compliance is mandatory**: If the selected CASE requires a tool/handoff, you MUST perform it. Do not answer directly without performing the required tool/handoff.
 - [Important!] Respond must in the language used by the user in their question. Regardless of the language returned by the tools being called, please return the results based on the language used in the user's query. For example, if user ask by English, you must return
 - Ensure that the commands or tools you invoke are within the provided tool list.
 - If the execution of a command or tool fails, try changing the parameters or their format before attempting again.