app/config.py

@@ -35,6 +35,7 @@ class Settings(BaseSettings):
     openrouter_api_key: str = ""
     openrouter_model: str = "google/gemini-2.5-flash-lite"
     openrouter_base_url: str = "https://openrouter.ai/api/v1"
+    gigachat_agent_model: str = "GigaChat-2-Pro"  # function calling quality matters more than price here
     chat_agent_timeout_s: float = 25.0
     chat_agent_max_steps: int = 5
 

app/llm/agent/__init__.py

@@ -22,6 +22,7 @@ from app.config import Settings, get_settings
 from app.core.types import ScrubbedText
 from app.llm.agent.prompts import SYSTEM_PROMPT
 from app.llm.agent.providers import (
+    GigaChatToolProvider,
     MockAgentProvider,
     OpenRouterProvider,
     ProviderError,
@@ -49,7 +50,7 @@ def build_provider(settings: Settings | None = None) -> ToolChatProvider | None:
     s = settings or get_settings()
     mode = s.chat_agent
     if mode == "auto":
-        mode = "openrouter" if s.openrouter_api_key else "off"
+        mode = "gigachat" if s.gigachat_credentials else "openrouter" if s.openrouter_api_key else "off"
     if mode == "openrouter":
         if not s.openrouter_api_key:
             log.warning("chat agent: openrouter selected without OPENROUTER_API_KEY — disabled")
@@ -58,15 +59,16 @@ def build_provider(settings: Settings | None = None) -> ToolChatProvider | None:
     if mode == "mock":
         return MockAgentProvider()
     if mode == "gigachat":
-        # TODO(GigaChat): function calling via the `gigachat` package (functions=..., message.function_call).
-        log.warning("chat agent: gigachat provider not implemented yet — disabled")
+        if not s.gigachat_credentials:
+            log.warning("chat agent: gigachat selected without GIGACHAT_CREDENTIALS — disabled")
             return None
+        return GigaChatToolProvider(s)
     return None
 
 
 async def _chat_with_retry(provider: ToolChatProvider, messages: list[dict[str, Any]]):
     """One retry: OpenRouter occasionally fails a single call (seen live as intermittent ProviderError)."""
-    wire = _wire(messages) if provider.name != "mock" else messages
+    wire = _wire(messages) if provider.name == "openrouter" else messages  # gigachat needs the tool `name`
     try:
         return await provider.chat(wire, TOOL_SPECS)
     except ProviderError as exc:
@@ -139,6 +141,9 @@ async def answer_chat(
     except (ProviderError, TimeoutError) as exc:
         log.error("chat agent provider=%s failed: %s %s", provider.name, type(exc).__name__, exc)
         return None
+    except Exception:  # noqa: BLE001 — the agent is optional: any bug must degrade to the extractive answer, not a 500
+        log.exception("chat agent provider=%s crashed", provider.name)
+        return None
 
 
 def _finish(text: str, ctx: ToolContext, provider: str) -> AgentAnswer | None:

app/llm/agent/providers.py

@@ -68,9 +68,10 @@ class OpenRouterProvider:
         if resp.status_code != 200:
             # Provider error bodies are generic (no patient text) — log the message to make failures diagnosable.
             try:
-                detail = str(resp.json().get("error", {}).get("message", ""))[:200]
-            except ValueError:
-                detail = ""
+                err = resp.json().get("error", "")
+                detail = str(err.get("message", "") if isinstance(err, dict) else err)[:200]
+            except (ValueError, AttributeError):
+                detail = resp.text[:200]
             log.error("openrouter http %s: %s", resp.status_code, detail)
             raise ProviderError(f"http {resp.status_code}")
         try:
@@ -90,6 +91,88 @@ class OpenRouterProvider:
         return AssistantTurn(content=msg.get("content"), tool_calls=calls)
 
 
+class GigaChatToolProvider:
+    """GigaChat function calling (RF provider, 152-FZ compliant). Converts the OpenAI-style history the agent keeps:
+    assistant `tool_calls` → `function_call`, `tool` results → role `function` with the function name.
+    GigaChat returns at most one function call per turn — the agent loop handles that naturally."""
+
+    name = "gigachat"
+
+    def __init__(self, settings: Settings, client: Any | None = None) -> None:
+        self._settings = settings
+        self._client = client
+
+    def _get_client(self) -> Any:
+        if self._client is None:
+            from gigachat import GigaChat
+
+            s = self._settings
+            self._client = GigaChat(
+                credentials=s.gigachat_credentials,
+                scope=s.gigachat_scope,
+                model=s.gigachat_agent_model,
+                verify_ssl_certs=s.gigachat_verify_ssl,
+                timeout=s.chat_agent_timeout_s,
+            )
+        return self._client
+
+    @staticmethod
+    def to_messages(messages: list[dict[str, Any]]) -> list[Any]:
+        from gigachat.models import FunctionCall, Messages, MessagesRole
+
+        out = []
+        for m in messages:
+            role = m["role"]
+            if role == "system":
+                out.append(Messages(role=MessagesRole.SYSTEM, content=m["content"]))
+            elif role == "user":
+                out.append(Messages(role=MessagesRole.USER, content=m["content"]))
+            elif role == "assistant":
+                calls = m.get("tool_calls") or []
+                for c in calls or [None]:
+                    fc = None
+                    if c is not None:
+                        fc = FunctionCall(name=c["function"]["name"], arguments=json.loads(c["function"]["arguments"]))
+                    out.append(Messages(role=MessagesRole.ASSISTANT, content=m.get("content") or "", function_call=fc))
+            elif role == "tool":
+                out.append(Messages(role=MessagesRole.FUNCTION, name=m.get("name"), content=m["content"]))
+        return out
+
+    @staticmethod
+    def to_functions(tools: list[dict[str, Any]]) -> list[Any]:
+        from gigachat.models import Function
+
+        return [Function.model_validate(t["function"]) for t in tools]
+
+    async def chat(self, messages: list[dict[str, Any]], tools: list[dict[str, Any]]) -> AssistantTurn:
+        from gigachat.models import Chat
+
+        chat = Chat(
+            messages=self.to_messages(messages),
+            functions=self.to_functions(tools),
+            function_call="auto",
+            temperature=0.1,
+            max_tokens=900,
+        )
+        try:
+            resp = await self._get_client().achat(chat)
+        except Exception as exc:  # noqa: BLE001 — network/auth/HTTP errors of the SDK
+            raise ProviderError(type(exc).__name__) from exc
+        msg = resp.choices[0].message
+        calls = []
+        if msg.function_call is not None:
+            args = msg.function_call.arguments or {}
+            if isinstance(args, str):
+                try:
+                    args = json.loads(args)
+                except json.JSONDecodeError:
+                    args = {}
+            calls.append(ToolCall(id=msg.function_call.name, name=msg.function_call.name, arguments=args))
+        usage = getattr(resp, "usage", None)
+        log.info("gigachat agent ok calls=%d tokens=%s", len(calls), getattr(usage, "total_tokens", None))
+        return AssistantTurn(content=msg.content or None, tool_calls=calls)
+
+
 # ------------------------------------------------------------------------------------------------ offline mock
 
 _DRUG_WORDS = re.compile(

tests/test_llm_agent.py

@@ -197,3 +197,75 @@ async def test_empty_final_answer_is_nudged(sertraline):
     assert ans is not None and "Алкоголь" in ans.text
     assert sent[0]["tool_choice"] == "required" and "tool_choice" not in sent[1]
     assert "сертралин" in sent[0]["messages"][0]["content"]  # patient brief in the system prompt
+
+
+async def test_region_block_string_error_degrades():
+    # Seen live from the RF server: 403 {"success": false, "error": "Access denied by security policy."}
+    client = httpx.AsyncClient(
+        transport=httpx.MockTransport(lambda r: httpx.Response(403, json={"success": False, "error": "Access denied"}))
+    )
+    provider = OpenRouterProvider(_settings(), client=client)
+    assert await agent.answer_chat(ANDREY, scrub("вопрос"), provider=provider, settings=_settings()) is None
+
+
+async def test_unexpected_provider_bug_degrades():
+    class Broken:
+        name = "broken"
+
+        async def chat(self, messages, tools):
+            raise AttributeError("boom")
+
+    assert await agent.answer_chat(ANDREY, scrub("вопрос"), provider=Broken(), settings=_settings()) is None
+
+
+# ------------------------------------------------------------------------------------------------- gigachat
+
+
+class _FakeGiga:
+    """Mimics gigachat.GigaChat.achat: first a function_call, then the final text."""
+
+    def __init__(self):
+        self.chats = []
+
+    async def achat(self, chat):
+        from types import SimpleNamespace as NS
+
+        self.chats.append(chat)
+        if len(self.chats) == 1:
+            fc = NS(name="check_drug_for_patient", arguments={"drug": "ибупрофен"})
+            msg = NS(content="", function_call=fc)
+        else:
+            msg = NS(
+                content="Ибупрофен вместе с сертралином повышает риск кровотечений. Обсудите с врачом.",
+                function_call=None,
+            )
+        return NS(choices=[NS(message=msg)], usage=NS(total_tokens=42))
+
+
+async def test_gigachat_tool_loop(sertraline):
+    from app.llm.agent.providers import GigaChatToolProvider
+
+    fake = _FakeGiga()
+    s = Settings(_env_file=None, chat_agent="gigachat", gigachat_credentials="x", chat_agent_timeout_s=5.0)
+    ans = await agent.answer_chat(
+        ANDREY, scrub("Можно ибупрофен?"), provider=GigaChatToolProvider(s, client=fake), settings=s
+    )
+    assert ans is not None and "кровотеч" in ans.text and ans.provider == "gigachat"
+    second = fake.chats[1]
+    roles = [str(m.role.value if hasattr(m.role, "value") else m.role) for m in second.messages]
+    assert roles == ["system", "user", "assistant", "function"]
+    assert second.messages[2].function_call.name == "check_drug_for_patient"
+    assert second.messages[3].name == "check_drug_for_patient"
+    assert {f.name for f in second.functions} == {
+        "search_guidelines",
+        "get_patient_record",
+        "get_drug_info",
+        "check_drug_for_patient",
+    }
+
+
+def test_build_provider_prefers_gigachat():
+    from app.llm.agent.providers import GigaChatToolProvider
+
+    s = Settings(_env_file=None, chat_agent="auto", gigachat_credentials="x", openrouter_api_key="y")
+    assert isinstance(agent.build_provider(s), GigaChatToolProvider)