fix(core): sanitize interrupted tool call arguments

Author: Alexxigang

agentscope-core/src/main/java/io/agentscope/core/agent/accumulator/ToolCallsAccumulator.java

@@ -0,0 +1,85 @@
+/*
+ * Copyright 2024-2026 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.agentscope.core.util;
+
+import java.util.Collections;
+import java.util.Map;
+
+/** Utility helpers for normalizing tool-call arguments stored as JSON strings. */
+public final class ToolCallJsonUtils {
+
+    private ToolCallJsonUtils() {}
+
+    /**
+     * Parse a raw JSON object string into a map.
+     *
+     * @param rawJson raw JSON object string
+     * @return parsed map, or empty map when the payload is blank or invalid
+     */
+    public static Map<String, Object> parseJsonObjectOrEmpty(String rawJson) {
+        if (rawJson == null || rawJson.isBlank()) {
+            return Collections.emptyMap();
+        }
+
+        try {
+            @SuppressWarnings("unchecked")
+            Map<String, Object> parsed = JsonUtils.getJsonCodec().fromJson(rawJson, Map.class);
+            return parsed != null ? parsed : Collections.emptyMap();
+        } catch (Exception ignored) {
+            return Collections.emptyMap();
+        }
+    }
+
+    /**
+     * Return a provider-safe JSON object string for tool call arguments.
+     *
+     * <p>Valid raw JSON is preserved as-is. Invalid or partial JSON falls back to serializing the
+     * structured input map, and ultimately to an empty JSON object.
+     *
+     * @param rawJson raw tool-call content accumulated from streaming chunks
+     * @param input structured tool-call input map
+     * @return safe JSON object string for downstream provider formatters
+     */
+    public static String sanitizeArgumentsJson(String rawJson, Map<String, Object> input) {
+        if (isValidJsonObject(rawJson)) {
+            return rawJson;
+        }
+        return serializeInputOrEmpty(input);
+    }
+
+    /**
+     * Check whether a raw tool-call payload is a valid JSON object.
+     *
+     * @param rawJson raw tool-call content
+     * @return true when the payload parses as a JSON object
+     */
+    public static boolean isValidJsonObject(String rawJson) {
+        return !parseJsonObjectOrEmpty(rawJson).isEmpty()
+                || (rawJson != null && "{}".equals(rawJson.trim()));
+    }
+
+    private static String serializeInputOrEmpty(Map<String, Object> input) {
+        if (input == null || input.isEmpty()) {
+            return "{}";
+        }
+
+        try {
+            return JsonUtils.getJsonCodec().toJson(input);
+        } catch (Exception ignored) {
+            return "{}";
+        }
+    }
+}