diff --git a/.gitignore b/.gitignore
index ae9ac7c..8b9c088 100644
--- a/.gitignore
+++ b/.gitignore
@@ -101,3 +101,4 @@ logs/
 Thumbs.db
 
 # Project specific
+backend/models_cache/
diff --git a/backend/app/api/router.py b/backend/app/api/router.py
index 1aece31..0bba686 100644
--- a/backend/app/api/router.py
+++ b/backend/app/api/router.py
@@ -1,10 +1,8 @@
 """API router aggregation."""
 
-from fastapi import APIRouter
-
 from app.api.routes.v1 import v1_router
 
-api_router = APIRouter()
-
-# API v1 routes (prefix is set in main.py via settings.API_V1_STR)
-api_router.include_router(v1_router)
+# Direct alias — avoids FastAPI 0.135+ validation that rejects routes with
+# empty raw paths (e.g. @router.get("")) when include_router has no prefix.
+# The prefix (settings.API_V1_STR) is applied in main.py.
+api_router = v1_router
diff --git a/backend/app/core/config.py b/backend/app/core/config.py
index b628a6c..5352564 100644
--- a/backend/app/core/config.py
+++ b/backend/app/core/config.py
@@ -9,10 +9,14 @@ from pydantic_settings import BaseSettings, SettingsConfigDict
 
 
 def find_env_file() -> Path | None:
-    """Find .env file in current or parent directories."""
+    """Find .env file in current, parent, or backend/ subdirectory."""
     current = Path.cwd()
-    for path in [current, current.parent]:
-        env_file = path / ".env"
+    for candidate in [
+        current,
+        current.parent,
+        current / "backend",
+    ]:
+        env_file = candidate / ".env"
         if env_file.exists():
             return env_file
     return None
diff --git a/backend/pyproject.toml b/backend/pyproject.toml
index 9806508..fdf8cab 100644
--- a/backend/pyproject.toml
+++ b/backend/pyproject.toml
@@ -60,6 +60,7 @@ dependencies = [
     # Cross-encoder reranking for RAG
     "sentence-transformers>=3.0.0",
     "torch>=2.0.0",
+    "httpx>=0.28.1",
 ]
 
 [project.optional-dependencies]
@@ -192,3 +193,8 @@ exclude_lines = [
 [tool.fastapi-fullstack]
 generator_version = "0.2.11"
 generated_at = "2026-06-15T06:18:30.904341+00:00"
+
+[dependency-groups]
+dev = [
+    "httpx>=0.28.1",
+]
diff --git a/backend/uv.lock b/backend/uv.lock
index 8505f13..85a778c 100644
--- a/backend/uv.lock
+++ b/backend/uv.lock
@@ -21,6 +21,7 @@ dependencies = [
     { name = "fastapi-cache2" },
     { name = "fastapi-pagination" },
     { name = "greenlet" },
+    { name = "httpx" },
     { name = "jinja2" },
     { name = "langchain-text-splitters" },
     { name = "logfire", extra = ["asyncpg", "fastapi", "redis"] },
@@ -62,6 +63,11 @@ dev = [
     { name = "ty" },
 ]
 
+[package.dev-dependencies]
+dev = [
+    { name = "httpx" },
+]
+
 [package.metadata]
 requires-dist = [
     { name = "alembic", specifier = ">=1.18.0" },
@@ -73,6 +79,7 @@ requires-dist = [
     { name = "fastapi-cache2", specifier = ">=0.2.2" },
     { name = "fastapi-pagination", specifier = ">=0.12.31" },
     { name = "greenlet", specifier = ">=3.2.0" },
+    { name = "httpx", specifier = ">=0.28.1" },
     { name = "httpx", marker = "extra == 'dev'", specifier = ">=0.28.0" },
     { name = "jinja2", specifier = ">=3.1.0" },
     { name = "langchain-text-splitters", specifier = ">=0.4.0" },
@@ -111,6 +118,9 @@ requires-dist = [
 ]
 provides-extras = ["dev"]
 
+[package.metadata.requires-dev]
+dev = [{ name = "httpx", specifier = ">=0.28.1" }]
+
 [[package]]
 name = "aiofile"
 version = "3.11.1"