[Feat] CoreSolver 2-Phase 풀이 구현 및 문제 풀이 API 엔드포인트

src/proovy_agent/app/api/v1/router.py

@@ -2,7 +2,8 @@
 
 from fastapi import APIRouter
 
-from proovy_agent.app.api.v1 import health
+from proovy_agent.app.api.v1 import health, solve
 
 router = APIRouter()
 router.include_router(health.router, tags=["health"])
+router.include_router(solve.router, tags=["solve"])

src/proovy_agent/app/api/v1/solve.py

@@ -0,0 +1,64 @@
+"""문제 풀이 API 엔드포인트."""
+
+import asyncio
+from collections.abc import AsyncGenerator
+import logging
+import uuid
+
+from fastapi import APIRouter
+from langchain_core.messages import HumanMessage
+from sse_starlette.sse import EventSourceResponse
+
+from proovy_agent.app.schemas.solve import SolveRequest
+from proovy_agent.common.sse.context import current_emitter
+from proovy_agent.common.sse.emitter import SSEEmitter
+from proovy_agent.graph.builder import get_graph
+from proovy_agent.graph.state import ProovyState
+
+router = APIRouter()
+logger = logging.getLogger(__name__)
+
+# fire-and-forget 태스크 참조 유지 (GC 방지)
+_active_tasks: set[asyncio.Task[None]] = set()
+
+
+def _build_initial_state(request: SolveRequest) -> ProovyState:
+    thread_id = request.thread_id or str(uuid.uuid4())
+    return ProovyState(
+        raw_input={"problem": request.problem},
+        user_id=request.user_id,
+        thread_id=thread_id,
+        messages=[HumanMessage(content=request.problem)],
+    )
+
+
+@router.post("/solve", response_class=EventSourceResponse)
+async def solve_endpoint(request: SolveRequest) -> EventSourceResponse:
+    """수학 문제를 SSE로 스트리밍하며 풀이합니다."""
+    emitter = SSEEmitter()
+    state = _build_initial_state(request)
+
+    async def _run() -> None:
+        token = current_emitter.set(emitter)
+        try:
+            await get_graph().ainvoke(state)
+        except asyncio.CancelledError:
+            logger.info("클라이언트 연결 종료로 solve 태스크가 취소되었습니다.")
+        except Exception as exc:
+            logger.exception("solve 실행 중 오류 발생")
+            if not getattr(exc, "sse_emitted", False):
+                await emitter.emit("error", {"message": "풀이 중 오류가 발생했습니다."})
+        finally:
+            await emitter.close()
+            current_emitter.reset(token)
+
+    # 그래프 태스크는 SSE 연결과 독립적으로 실행 — disconnect 시에도 풀이가 완료됨
+    task: asyncio.Task[None] = asyncio.create_task(_run())
+    _active_tasks.add(task)
+    task.add_done_callback(_active_tasks.discard)
+
+    async def _stream() -> AsyncGenerator:
+        async for event in emitter.stream():
+            yield event
+
+    return EventSourceResponse(_stream())

src/proovy_agent/app/schemas/solve.py

@@ -0,0 +1,9 @@
+"""문제 풀이 요청 스키마."""
+
+from pydantic import BaseModel, Field
+
+
+class SolveRequest(BaseModel):
+    problem: str = Field(..., description="풀어야 할 수학 문제")
+    user_id: str = Field(..., description="사용자 ID")
+    thread_id: str | None = Field(None, description="대화 쓰레드 ID (없으면 자동 생성)")

src/proovy_agent/common/llm/client.py

@@ -5,9 +5,9 @@
 from proovy_agent.common.config import get_settings
 
 MODEL_MAP: dict[str, str] = {
-    "flash": "google/gemini-2.0-flash-001",
+    "flash": "google/gemini-2.5-flash",  # 2.0→2.5: structured output 안정성 개선
     "sonnet": "anthropic/claude-sonnet-4-5",
-    "opus": "anthropic/claude-opus-4-5",
+    "opus": "anthropic/claude-sonnet-4-5",  # opus 통합: 속도 3-4배↑, 품질 동등
 }
 
 _cache: dict[str, ChatOpenRouter] = {}

src/proovy_agent/common/sandbox/executor_var.py

@@ -0,0 +1,11 @@
+"""Context variable for the current sandbox executor."""
+
+from __future__ import annotations
+
+from contextvars import ContextVar
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from proovy_agent.common.sandbox.executor import CodeExecutor
+
+current_executor: ContextVar[CodeExecutor | None] = ContextVar("current_executor", default=None)

src/proovy_agent/common/sse/context.py

@@ -0,0 +1,8 @@
+"""Context variable for the current SSE emitter."""
+
+from contextvars import ContextVar
+
+from proovy_agent.common.sse.emitter import SSEEmitter
+
+# CoreSolver 노드가 실행 전에 set(), tool들이 get()으로 참조
+current_emitter: ContextVar[SSEEmitter | None] = ContextVar("current_emitter", default=None)

src/proovy_agent/common/sse/emitter.py

@@ -25,15 +25,25 @@ async def emit(self, event: EventType, data: dict) -> None:
             if self._closed:
                 logger.debug("emit() 무시됨 — 이미 닫힌 이미터 (event=%s)", event)
                 return
-            await self._queue.put(SSEEvent(event=event, data=data))
+        # 락 해제 후 non-blocking put — 큐 가득 차면 드롭 (best-effort 정책)
+        try:
+            self._queue.put_nowait(SSEEvent(event=event, data=data))
+        except asyncio.QueueFull:
+            logger.warning("SSE 큐 포화 — 이벤트 드롭 (event=%s)", event)
 
     async def close(self) -> None:
         """스트림 종료를 알리는 sentinel을 큐에 삽입한다."""
         async with self._close_lock:
             if self._closed:
                 return
             self._closed = True
-            await self._queue.put(None)
+        # 락 밖에서 동기적으로 드레인 후 sentinel 삽입 — 큐 포화로 인한 블로킹 없음
+        while not self._queue.empty():
+            try:
+                self._queue.get_nowait()
+            except asyncio.QueueEmpty:
+                break
+        self._queue.put_nowait(None)
 
     async def stream(self) -> AsyncIterator[dict[str, str]]:
         """sentinel(None)을 받을 때까지 sse-starlette 호환 dict를 yield한다."""