fix: ensure Gemini array schemas always include items

astrbot/core/agent/tool.py

@@ -293,8 +293,15 @@ def convert_schema(schema: dict) -> dict:
                 if properties:
                     result["properties"] = properties
 
-            if "items" in schema:
-                result["items"] = convert_schema(schema["items"])
+            if target_type == "array":
+                items_schema = schema.get("items")
+                if isinstance(items_schema, dict):
+                    result["items"] = convert_schema(items_schema)
+                else:
+                    # Gemini requires array schemas to include an `items` schema.
+                    # JSON Schema allows omitting it, so fall back to a permissive
+                    # string item schema instead of emitting an invalid declaration.
+                    result["items"] = {"type": "string"}
 
             return result
 

tests/unit/test_tool_google_schema.py

@@ -0,0 +1,77 @@
+from __future__ import annotations
+
+import importlib.util
+import sys
+import types
+from pathlib import Path
+from typing import Generic, TypeVar
+
+REPO_ROOT = Path(__file__).resolve().parents[2]
+TOOL_MODULE_PATH = REPO_ROOT / "astrbot/core/agent/tool.py"
+
+
+def load_tool_module():
+    package_names = [
+        "astrbot",
+        "astrbot.core",
+        "astrbot.core.agent",
+        "astrbot.core.message",
+    ]
+    for name in package_names:
+        if name not in sys.modules:
+            module = types.ModuleType(name)
+            module.__path__ = []
+            sys.modules[name] = module
+
+    message_result_module = types.ModuleType(
+        "astrbot.core.message.message_event_result"
+    )
+    message_result_module.MessageEventResult = type("MessageEventResult", (), {})
+    sys.modules[message_result_module.__name__] = message_result_module
+
+    run_context_module = types.ModuleType("astrbot.core.agent.run_context")
+    run_context_module.TContext = TypeVar("TContext")
+
+    class ContextWrapper(Generic[run_context_module.TContext]):
+        pass
+
+    run_context_module.ContextWrapper = ContextWrapper
+    sys.modules[run_context_module.__name__] = run_context_module
+
+    spec = importlib.util.spec_from_file_location(
+        "astrbot.core.agent.tool", TOOL_MODULE_PATH
+    )
+    assert spec and spec.loader
+    module = importlib.util.module_from_spec(spec)
+    sys.modules[spec.name] = module
+    spec.loader.exec_module(module)
+    return module
+
+
+def test_google_schema_fills_missing_array_items_with_string_schema():
+    tool_module = load_tool_module()
+    FunctionTool = tool_module.FunctionTool
+    ToolSet = tool_module.ToolSet
+
+    tool = FunctionTool(
+        name="search_sources",
+        description="Search sources by UUID.",
+        parameters={
+            "type": "object",
+            "properties": {
+                "source_uuids": {
+                    "type": "array",
+                    "description": "Optional list of source UUIDs.",
+                }
+            },
+            "required": ["source_uuids"],
+        },
+    )
+
+    schema = ToolSet([tool]).google_schema()
+    source_uuids = schema["function_declarations"][0]["parameters"]["properties"][
+        "source_uuids"
+    ]
+
+    assert source_uuids["type"] == "array"
+    assert source_uuids["items"] == {"type": "string"}