fix(a2a): allow LiteLLMSendMessageResponse.id to be str | int | None (LIT-2818)

litellm/types/agents.py

@@ -307,7 +307,16 @@ class LiteLLMSendMessageResponse(LiteLLMPydanticObjectBase):
     """
 
     # A2A response fields
-    id: str
+    #
+    # Per JSON-RPC 2.0, the response ``id`` MAY be a string, a number, or
+    # ``null`` (an error response that could not be correlated to a request
+    # MUST use ``null``). The upstream a2a SDK matches this contract with
+    # ``id: str | int | None = None`` on both ``SendMessageSuccessResponse``
+    # and ``JSONRPCErrorResponse``. Pinning ``id: str`` (required) here
+    # made the proxy raise ``ValidationError`` on legitimate JSON-RPC error
+    # responses (numeric or null id), surfacing as a 500 on the
+    # error-response path. Track the SDK contract instead.
+    id: Optional[Union[str, int]] = None
     jsonrpc: str = "2.0"
     result: Optional[Dict[str, Any]] = None
     error: Optional[Dict[str, Any]] = None

tests/test_litellm/a2a_protocol/test_send_message_response_id_lit2818.py

@@ -0,0 +1,122 @@
+"""Regression tests for LIT-2818 - LiteLLMSendMessageResponse must accept
+the full JSON-RPC 2.0 id contract: str, int, or None.
+
+Before LIT-2818, LiteLLMSendMessageResponse declared id: str (required).
+Per JSON-RPC 2.0 the response id may be a String, Number, or Null;
+error responses that could not be correlated to a request MUST use null.
+The upstream a2a SDK (a2a-sdk==0.3.24) reflects this on both
+SendMessageSuccessResponse and JSONRPCErrorResponse:
+    id: str | int | None = None
+Pinning id: str (required) here made the proxy raise a Pydantic
+ValidationError whenever an upstream agent returned a legitimate JSON-RPC
+error response with a numeric or null id - surfacing as a 500.
+"""
+
+from typing import Any, Dict
+
+import pytest
+from pydantic import ValidationError
+
+from litellm.types.agents import LiteLLMSendMessageResponse
+
+
+def test_lit2818_constructor_accepts_string_id():
+    r = LiteLLMSendMessageResponse(
+        id="req-abc-123",
+        result={"kind": "task", "id": "task-1"},
+    )
+    assert r.id == "req-abc-123"
+    assert r.jsonrpc == "2.0"
+
+
+def test_lit2818_constructor_accepts_integer_id():
+    # Per JSON-RPC 2.0 id may be a Number. Pre-fix raised:
+    # ValidationError: Input should be a valid string.
+    r = LiteLLMSendMessageResponse(
+        id=42,
+        result={"kind": "message"},
+    )
+    assert r.id == 42
+
+
+def test_lit2818_constructor_accepts_null_id():
+    # JSON-RPC 2.0: error responses that could not be correlated to a
+    # request MUST use null id.
+    r = LiteLLMSendMessageResponse(
+        id=None,
+        error={"code": -32700, "message": "Parse error"},
+    )
+    assert r.id is None
+
+
+def test_lit2818_constructor_accepts_missing_id_defaults_to_none():
+    r = LiteLLMSendMessageResponse(
+        error={"code": -32600, "message": "Invalid Request"},
+    )
+    assert r.id is None
+
+
+def _error_response_dict(rpc_id):
+    return {
+        "jsonrpc": "2.0",
+        "id": rpc_id,
+        "error": {"code": -32603, "message": "Internal error"},
+    }
+
+
+@pytest.mark.parametrize(
+    "rpc_id",
+    [
+        "req-error-1",
+        42,
+        None,
+    ],
+)
+def test_lit2818_from_dict_error_response_accepts_all_jsonrpc_id_shapes(rpc_id):
+    r = LiteLLMSendMessageResponse.from_dict(_error_response_dict(rpc_id))
+    assert r.id == rpc_id
+    assert r.error is not None
+    assert r.error["code"] == -32603
+
+
+def test_lit2818_from_dict_omitted_id_does_not_raise():
+    r = LiteLLMSendMessageResponse.from_dict(
+        {
+            "jsonrpc": "2.0",
+            "error": {"code": -32700, "message": "Parse error"},
+        }
+    )
+    assert r.id is None
+    assert r.error["code"] == -32700
+
+
+def _build_jsonrpc_error_response(rpc_id):
+    from a2a.types import JSONRPCError, JSONRPCErrorResponse, SendMessageResponse
+
+    err = JSONRPCErrorResponse(
+        id=rpc_id,
+        error=JSONRPCError(code=-32603, message="Internal error"),
+    )
+    return SendMessageResponse(root=err)
+
+
+@pytest.mark.parametrize("rpc_id", ["req-1", 7, None])
+def test_lit2818_from_a2a_response_error_path(rpc_id):
+    sdk_response = _build_jsonrpc_error_response(rpc_id)
+    wrapped = LiteLLMSendMessageResponse.from_a2a_response(sdk_response)
+    assert wrapped.id == rpc_id
+    assert wrapped.error is not None
+    assert wrapped.error["code"] == -32603
+
+
+@pytest.mark.parametrize(
+    "bad_id",
+    [
+        12.34,
+        ["arr"],
+        {"o": "bj"},
+    ],
+)
+def test_lit2818_constructor_still_rejects_invalid_id_shapes(bad_id):
+    with pytest.raises(ValidationError):
+        LiteLLMSendMessageResponse(id=bad_id)