fix(python): reject malformed finish reasons

python/sdk/tests/test_client.py

@@ -9,7 +9,7 @@ from pathlib import Path
 
 import pytest
 
-from deepseek_harness import DeepSeekHarness, HarnessClient, HarnessConfig, Notification
+from deepseek_harness import DeepSeekHarness, HarnessClient, HarnessConfig, Notification, SdkProtocolError
 
 
 def test_high_level_sdk_runs_turn_and_collects_final_response(tmp_path: Path) -> None:
@@ -69,6 +69,17 @@ for line in sys.stdin:
                 },
             },
         }), flush=True)
+        print(json.dumps({
+            "jsonrpc": "2.0",
+            "method": "session.event",
+            "params": {
+                "sessionId": params["sessionId"],
+                "event": {
+                    "type": "turn/end",
+                    "data": {"turn": 2, "reason": {"kind": "max-tokens"}},
+                },
+            },
+        }), flush=True)
         print(json.dumps({
             "jsonrpc": "2.0",
             "method": "session.status",
@@ -97,7 +108,7 @@ for line in sys.stdin:
         result = harness.run("say hello", session_id="main")
 
     assert result.final_response == "hello from runtime"
-    assert result.finish_reason == "completed"
+    assert result.finish_reason == "max-tokens"
     assert result.events[-1]["type"] == "turn/end"
     dumped_env = json.loads(env_dump.read_text())
     assert dumped_env["DEEPSEEK_API_KEY"] == "env-key"
@@ -152,6 +163,41 @@ for line in sys.stdin:
     assert result.finish_reason is None
 
 
+def test_high_level_sdk_rejects_turn_end_without_reason_kind(tmp_path: Path) -> None:
+    script = tmp_path / "fake_runtime.py"
+    script.write_text(
+        """
+import json
+import sys
+
+for line in sys.stdin:
+    msg = json.loads(line)
+    method = msg.get("method")
+    if method == "initialize":
+        print(json.dumps({"jsonrpc": "2.0", "id": msg["id"], "result": {"serverInfo": {"name": "fake-runtime"}}}), flush=True)
+    elif method == "session/prompt":
+        params = msg.get("params") or {}
+        print(json.dumps({"jsonrpc": "2.0", "method": "session.event", "params": {"sessionId": params["sessionId"], "event": {"type": "agent/inbox/spliced", "data": {"target": "next-turn", "start": 0, "inserted": [{"id": "message-1"}]}}}}), flush=True)
+        print(json.dumps({"jsonrpc": "2.0", "id": msg["id"], "result": {"messageId": "message-1"}}), flush=True)
+        print(json.dumps({"jsonrpc": "2.0", "method": "session.event", "params": {"sessionId": params["sessionId"], "event": {"type": "turn/end", "data": {"turn": 1, "reason": {}}}}}), flush=True)
+        print(json.dumps({"jsonrpc": "2.0", "method": "session.status", "params": {"sessionId": params["sessionId"], "status": "idle"}}), flush=True)
+    elif method == "shutdown":
+        print(json.dumps({"jsonrpc": "2.0", "id": msg["id"], "result": {}}), flush=True)
+        break
+""".strip()
+    )
+
+    with DeepSeekHarness(
+        launch_args_override=(sys.executable, str(script)),
+        cwd=str(tmp_path),
+    ) as harness:
+        with pytest.raises(
+            SdkProtocolError,
+            match=r"turn/end event requires a string data\.reason\.kind",
+        ):
+            harness.run("reject malformed turn ending", session_id="main")
+
+
 def test_relative_cwd_is_absolute_in_process_environment_and_wire(
     tmp_path: Path, monkeypatch: pytest.MonkeyPatch
 ) -> None: