fix: report Python SDK identity and package version in User-Agent

src/arkruntime/_base_client.py

@@ -184,7 +184,7 @@ def auth_headers(self) -> dict[str, str]:
 
     @property
     def user_agent(self) -> str:
-        return "volc-sdk-python/" + VERSION
+        return "ark-runtime-python/" + VERSION
 
     def default_headers(self) -> Dict[str, str]:
         return {

src/arkruntime/_constants.py

@@ -4,7 +4,8 @@
 
 import httpx
 
-VERSION = "1.0.0"
+from ._version import VERSION as VERSION
+
 BASE_URL = "https://ark.cn-beijing.volces.com/api/v3"
 
 

src/arkruntime/_version.py

@@ -0,0 +1,27 @@
+# Copyright (c) 2026 ByteDance Ltd. and/or its affiliates.
+# SPDX-License-Identifier: Apache-2.0
+
+import re
+from importlib.metadata import version
+from pathlib import Path
+
+
+def _get_version() -> str:
+    # Source and editable imports must use this checkout, even if another
+    # arkruntime distribution is installed. Releases use wheel metadata,
+    # which setuptools derives from the same pyproject.toml project.version.
+    source_root = Path(__file__).resolve().parent.parent
+    pyproject = source_root.parent / "pyproject.toml"
+    if source_root.name == "src" and pyproject.is_file():
+        # The project declares a static, single-line version. Read only the
+        # [project] table without requiring a TOML dependency on Python 3.8.
+        project = re.search(r"(?ms)^\[project\][ \t]*\n(.*?)(?=^\[|\Z)", pyproject.read_text(encoding="utf-8"))
+        if project is not None:
+            declared = re.search(r"""(?m)^version\s*=\s*["']([^"'\r\n]+)["'][ \t]*(?:#.*)?$""", project[1])
+            if declared is not None:
+                return declared[1]
+        raise RuntimeError("Expected a static project.version in " + str(pyproject))
+    return version("arkruntime")
+
+
+VERSION = _get_version()

tests/test_user_agent.py

@@ -0,0 +1,71 @@
+# Copyright (c) 2026 ByteDance Ltd. and/or its affiliates.
+# SPDX-License-Identifier: Apache-2.0
+
+from __future__ import annotations
+
+import asyncio
+from importlib.metadata import version
+from pathlib import Path
+
+import httpx
+import pytest
+
+from arkruntime import Ark, AsyncArk, _version
+
+
+@pytest.mark.parametrize("custom", [None, "my-app/2.0"])
+@pytest.mark.parametrize("asynchronous", [False, True])
+def test_user_agent_on_requests(custom: str | None, asynchronous: bool) -> None:
+    requests = []
+
+    def handle(request: httpx.Request) -> httpx.Response:
+        requests.append(request)
+        return httpx.Response(200, json={"id": "test-file", "object": "file"})
+
+    headers = {"User-Agent": custom} if custom else {}
+    transport = httpx.MockTransport(handle)
+    if asynchronous:
+
+        async def run() -> None:
+            async with AsyncArk(api_key="placeholder", http_client=httpx.AsyncClient(transport=transport)) as client:
+                await client.files.retrieve("test-file", extra_headers=headers)
+
+        asyncio.run(run())
+    else:
+        with Ark(api_key="placeholder", http_client=httpx.Client(transport=transport)) as client:
+            client.files.retrieve("test-file", extra_headers=headers)
+
+    assert len(requests) == 1
+    assert requests[0].headers.get_list("User-Agent") == [custom or "ark-runtime-python/" + version("arkruntime")]
+
+
+def test_checkout_version_takes_precedence_over_installed_metadata(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    source = tmp_path / "src" / "arkruntime" / "_version.py"
+    monkeypatch.setattr(_version, "__file__", str(source))
+    monkeypatch.setattr(_version, "version", lambda name: "0.0.1")
+    (tmp_path / "pyproject.toml").write_text(
+        '[tool.example]\nversion = "9.9.9"\n[project]\nname = "arkruntime"\nversion = "2.3.4rc1"\n'
+        '[tool.other]\nversion = "8.8.8"\n',
+        encoding="utf-8",
+    )
+    assert _version._get_version() == "2.3.4rc1"
+
+
+def test_installed_version_uses_distribution_metadata(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setattr(_version, "__file__", str(tmp_path / "site-packages" / "arkruntime" / "_version.py"))
+
+    def metadata_version(name: str) -> str:
+        assert name == "arkruntime"
+        return "3.4.5"
+
+    monkeypatch.setattr(_version, "version", metadata_version)
+    assert _version._get_version() == "3.4.5"
+
+
+def test_missing_source_version_does_not_use_stale_metadata(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setattr(_version, "__file__", str(tmp_path / "src" / "arkruntime" / "_version.py"))
+    (tmp_path / "pyproject.toml").write_text('[project]\nname = "arkruntime"\n', encoding="utf-8")
+    with pytest.raises(RuntimeError, match="Expected a static project.version"):
+        _version._get_version()