fix: Python 3.9 compatibility for HuggingFace Spaces

- Replace Python 3.10+ union syntax (str | None) with Optional[str]
- Replace list[T] with List[T] from typing module
- HuggingFace Spaces uses Python 3.9 which doesn't support PEP 604 syntax
- Fixes TypeError: unsupported operand type(s) for |
- Note: Ignoring ruff UP035/UP006 as we need Python 3.9 compatibility

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

backend/api/agents.py

@@ -1,5 +1,7 @@
 """API endpoints for agent management"""
 
+from typing import List, Optional
+
 from fastapi import APIRouter, Depends, HTTPException
 from pydantic import BaseModel
 from sqlalchemy import select
@@ -14,22 +16,22 @@ router = APIRouter(prefix="/api/agents", tags=["agents"])
 class AgentCreate(BaseModel):
     slug: str
     name: str
-    description: str | None = None
+    description: Optional[str] = None
     status: str = "draft"
 
 
 class AgentVersionCreate(BaseModel):
     config_json: dict
-    created_by: str | None = None
+    created_by: Optional[str] = None
 
 
 class AgentResponse(BaseModel):
     id: int
     slug: str
     name: str
-    description: str | None
+    description: Optional[str]
     status: str
-    active_version_id: int | None
+    active_version_id: Optional[int]
 
 
 class AgentVersionResponse(BaseModel):
@@ -40,7 +42,7 @@ class AgentVersionResponse(BaseModel):
     config_json: dict
 
 
-@router.get("/", response_model=list[AgentResponse])
+@router.get("/", response_model=List[AgentResponse])
 async def list_agents(db: AsyncSession = Depends(get_db)):
     """List all agents"""
 
@@ -120,7 +122,7 @@ async def get_agent(agent_id: int, db: AsyncSession = Depends(get_db)):
         raise HTTPException(status_code=500, detail=f"Failed to get agent: {str(e)}") from e
 
 
-@router.get("/{agent_id}/versions", response_model=list[AgentVersionResponse])
+@router.get("/{agent_id}/versions", response_model=List[AgentVersionResponse])
 async def list_agent_versions(agent_id: int, db: AsyncSession = Depends(get_db)):
     """List all versions for an agent"""
 

backend/api/chat.py

@@ -1,5 +1,7 @@
 """API endpoints for RAG-powered chat"""
 
+from typing import List, Optional
+
 from fastapi import APIRouter, Depends, HTTPException
 from pydantic import BaseModel
 from sqlalchemy import Float, Integer, String, bindparam, text
@@ -15,7 +17,7 @@ class ChatRequest(BaseModel):
     question: str
     top_k: int = 7  # Increased for better coverage with 59 chunks
     similarity_threshold: float = 0.55  # Balanced threshold for quality results
-    system_prompt: str | None = None
+    system_prompt: Optional[str] = None
     temperature: float = 0.6  # Lowered for more accurate responses
 
 
@@ -30,7 +32,7 @@ class Citation(BaseModel):
 class ChatResponse(BaseModel):
     question: str
     answer: str
-    citations: list[Citation]
+    citations: List[Citation]
     total_citations: int
 
 

backend/api/search.py

@@ -1,5 +1,7 @@
 """API endpoints for vector similarity search"""
 
+from typing import List
+
 from fastapi import APIRouter, Depends, HTTPException
 from pydantic import BaseModel
 from sqlalchemy import Float, Integer, String, bindparam, text
@@ -28,7 +30,7 @@ class SearchResult(BaseModel):
 
 class SearchResponse(BaseModel):
     query: str
-    results: list[SearchResult]
+    results: List[SearchResult]
     total_results: int
 
 

backend/api/stats.py

@@ -1,5 +1,7 @@
 """API endpoints for database statistics"""
 
+from typing import List
+
 from fastapi import APIRouter, Depends
 from pydantic import BaseModel
 from sqlalchemy import text
@@ -25,7 +27,7 @@ class DatabaseStats(BaseModel):
     total_chunks: int
     total_embeddings: int
     total_bytes: int
-    documents: list[DocumentStats]
+    documents: List[DocumentStats]
 
 
 @router.get("/", response_model=DatabaseStats)
@@ -92,7 +94,7 @@ class ChunkDetail(BaseModel):
     document_title: str
 
 
-@router.get("/chunks/{doc_id}", response_model=list[ChunkDetail])
+@router.get("/chunks/{doc_id}", response_model=List[ChunkDetail])
 async def get_document_chunks(doc_id: int, db: AsyncSession = Depends(get_db)):
     """
     Get all chunks for a specific document