lmproto: add DeepSeek Anthropic client

src/plyngent/agent/types.py

@@ -3,10 +3,19 @@
 from __future__ import annotations
 
 from plyngent.lmproto.anthropic.client import AnthropicClient
-from plyngent.lmproto.deepseek import DeepseekOpenAIClient, DeepseekResponsesClient
+from plyngent.lmproto.deepseek import (
+    DeepseekAnthropicClient,
+    DeepseekOpenAIClient,
+    DeepseekResponsesClient,
+)
 from plyngent.lmproto.openai.client import OpenAIClient
 from plyngent.lmproto.openai_compatible.client import OpenAICompatibleClient
 
 type AnyLLMClient = (
-    OpenAICompatibleClient | DeepseekOpenAIClient | DeepseekResponsesClient | OpenAIClient | AnthropicClient
+    OpenAICompatibleClient
+    | DeepseekOpenAIClient
+    | DeepseekResponsesClient
+    | DeepseekAnthropicClient
+    | OpenAIClient
+    | AnthropicClient
 )

src/plyngent/lmproto/deepseek/__init__.py

@@ -1,3 +1,4 @@
+from .anthropic.client import DeepseekAnthropicClient as DeepseekAnthropicClient
 from .openai_compat.client import DeepseekOpenAIClient as DeepseekOpenAIClient
 from .openai_compat.model import AnyChatMessage as AnyChatMessage
 from .openai_compat.model import AssistantChatMessage as AssistantChatMessage

src/plyngent/lmproto/deepseek/anthropic/__init__.py

@@ -0,0 +1 @@
+from .client import DeepseekAnthropicClient as DeepseekAnthropicClient

src/plyngent/lmproto/deepseek/anthropic/client.py

@@ -0,0 +1,35 @@
+"""DeepSeek Anthropic Messages client (``POST /messages`` on the DeepSeek endpoint)."""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, override
+
+from plyngent.lmproto.anthropic.client import AnthropicClient
+
+if TYPE_CHECKING:
+    from plyngent.lmproto.anthropic.config import AnthropicConfig
+
+
+class DeepseekAnthropicClient(AnthropicClient):
+    """Anthropic Messages client pointed at DeepSeek's Anthropic-compatible endpoint.
+
+    DeepSeek exposes the Anthropic API format at ``https://api.deepseek.com/anthropic``
+    (see https://api-docs.deepseek.com/guides/anthropic_api). ``x-api-key`` is fully
+    supported; ``anthropic-version`` / ``anthropic-beta`` headers are ignored by the
+    server but harmless. Model ids map server-side: ``claude-opus*`` → ``deepseek-v4-pro``,
+    ``claude-haiku*`` / ``claude-sonnet*`` → ``deepseek-v4-flash``, unknown names →
+    ``deepseek-v4-flash``; real DeepSeek ids pass through as-is.
+
+    ``GET /models`` is not documented on the ``/anthropic`` base, so ``models()``
+    returns an empty list and model selection stays config-driven.
+    """
+
+    kind: str = "messages"
+
+    def __init__(self, config: AnthropicConfig) -> None:
+        super().__init__(config)
+
+    @override
+    async def models(self) -> list[str]:
+        """No documented ``GET /models`` on DeepSeek's ``/anthropic`` base."""
+        return []

tests/test_lmproto/test_deepseek_anthropic.py

@@ -0,0 +1,95 @@
+from __future__ import annotations
+
+import msgspec
+import pytest
+
+from plyngent.lmproto.anthropic.config import AnthropicConfig
+from plyngent.lmproto.anthropic.model import (
+    AnthropicMessageResponse,
+    AnthropicMessagesParam,
+    AnthropicResponseText,
+    AnthropicUsage,
+)
+from plyngent.lmproto.deepseek import DeepseekAnthropicClient
+
+
+def _sample_message_body() -> bytes:
+    return msgspec.json.encode(
+        AnthropicMessageResponse(
+            id="msg_1",
+            model="deepseek-v4-flash",
+            content=[AnthropicResponseText(text="hello world")],
+            stop_reason="end_turn",
+            usage=AnthropicUsage(input_tokens=9, output_tokens=3),
+        )
+    )
+
+
+def test_client_kind_and_base_url() -> None:
+    client = DeepseekAnthropicClient(AnthropicConfig(api_key="sk-test", base_url="https://api.deepseek.com/anthropic"))
+    assert client.kind == "messages"
+    assert client.session.base_url == "https://api.deepseek.com/anthropic"
+
+
+@pytest.mark.asyncio
+async def test_client_messages_create(monkeypatch: pytest.MonkeyPatch) -> None:
+    client = DeepseekAnthropicClient(AnthropicConfig(api_key="sk-test", base_url="https://api.deepseek.com/anthropic"))
+
+    class _Resp:
+        status_code = 200
+
+        @property
+        def content(self) -> bytes:
+            return _sample_message_body()
+
+    async def fake_post(path: str, **kwargs: object) -> _Resp:
+        assert path == "/messages"
+        assert kwargs.get("stream") is False
+        headers = kwargs.get("headers")
+        assert isinstance(headers, dict)
+        assert headers.get("x-api-key") == "sk-test"
+        assert "anthropic-version" in headers
+        return _Resp()
+
+    monkeypatch.setattr(client.session, "post", fake_post)
+    result = await client.messages(AnthropicMessagesParam(model="deepseek-v4-flash", messages=[]))
+    assert isinstance(result, AnthropicMessageResponse)
+    assert result.content[0].text == "hello world"
+    assert result.usage.output_tokens == 3
+
+
+@pytest.mark.asyncio
+async def test_client_messages_stream(monkeypatch: pytest.MonkeyPatch) -> None:
+    client = DeepseekAnthropicClient(AnthropicConfig(api_key="sk-test", base_url="https://api.deepseek.com/anthropic"))
+
+    class _Resp:
+        status_code = 200
+
+        async def iter_lines(self):
+            yield b'data: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":"hel"}}'
+            yield b'data: {"type":"message_stop"}'
+
+        def close(self) -> None:
+            return None
+
+    async def fake_post(path: str, **kwargs: object) -> _Resp:
+        assert path == "/messages"
+        assert kwargs.get("stream") is True
+        return _Resp()
+
+    monkeypatch.setattr(client.session, "post", fake_post)
+    stream = await client.messages(AnthropicMessagesParam(model="deepseek-v4-flash", messages=[]), stream=True)
+    events = [event async for event in stream]
+    assert len(events) == 2
+
+
+@pytest.mark.asyncio
+async def test_client_models_empty_without_network(monkeypatch: pytest.MonkeyPatch) -> None:
+    client = DeepseekAnthropicClient(AnthropicConfig(api_key="sk-test", base_url="https://api.deepseek.com/anthropic"))
+
+    async def fail_get(*_args: object, **_kwargs: object) -> object:
+        msg = "GET /models must not be called on the /anthropic base"
+        raise AssertionError(msg)
+
+    monkeypatch.setattr(client.session, "get", fail_get)
+    assert await client.models() == []