feat: add strict schema enforcement and strip hallucinated fields from tool call parameters

internal/util/tool_prompt.go

@@ -53,6 +53,7 @@ RULES:
 5) After receiving a tool result, use it directly. Only call another tool if the result is insufficient.
 6) If you want to say something AND call a tool, output text first, then the XML block on its own.
 7) Parameters MUST use the exact field names from the selected tool schema.
+8) CRITICAL: Do NOT invent or add any extra fields (such as "_raw", "_xml"). Use ONLY the fields strictly defined in the schema. Extra fields will cause execution failure.
 
 ❌ WRONG — Do NOT do these:
 Wrong 1 — mixed text and XML:
@@ -61,6 +62,9 @@ Wrong 2 — describing tool calls in text:
   [调用 Bash] {"command": "ls"}
 Wrong 3 — missing <tool_calls> wrapper:
   <tool_call><tool_name>` + ex1 + `</tool_name><parameters>{}</parameters></tool_call>
+Wrong 4 — extra/invented fields:
+  <parameters>{"_raw": "...", "command": "ls"}</parameters>
+
 
 ✅ CORRECT EXAMPLES:
 

internal/util/toolcalls_parse.go

@@ -158,6 +158,10 @@ func filterToolCallsDetailed(parsed []ParsedToolCall, availableToolNames []strin
 		}
 		if tc.Input == nil {
 			tc.Input = map[string]any{}
+		} else {
+			// Remove known hallucinated fields often generated by models trying to bridge XML and JSON
+			delete(tc.Input, "_raw")
+			delete(tc.Input, "_xml")
 		}
 		out = append(out, tc)
 	}