ContextForge: Agentic RAG Backend Skeleton and Production-Grade Architecture Practice for Engineering Teams

ContextForge is an Agentic RAG backend skeleton designed for engineering teams, aiming to bridge the gap between prototype-level RAG and production-grade architecture. It is not a complete product but a reference implementation that shows how to build a production RAG system with clear API contracts, service boundaries, adapter interfaces, and observability. Core features include explicit API definitions, pluggable architecture, full-link tracing, and evaluation-ready design, helping teams move from demos to maintainable and scalable production environments.

Most current RAG demo projects remain at the "document upload + chat" level, lacking the engineering rigor required for production environments. As an open-source project, ContextForge aims to provide a "skeleton" for engineering teams, guiding them on how to build a production backend with clear API contracts, service boundaries, adapter interfaces, and observability, solving the transition challenge from prototype to production.

ContextForge's design philosophy differs from common RAG tutorials, emphasizing four points: explicit API contracts (Pydantic models define service boundaries), pluggable architecture (adapter pattern isolates technical implementations), traceability (complete records of retrieval/Agent/tool calls), and evaluation readiness (built-in hooks for integration with frameworks like Ragas). The system uses FastAPI to expose four core services: Document Ingestion Service (handles text chunking and storage), Retrieval Service (Mock keyword matching, reserved for pgvector extension), Agent Service (LangGraph-style state machine workflow), and Evaluation Service (placeholder interface for Ragas integration).

The project implements pluggable adapters via abstract base classes: BaseEmbeddingProvider (embedding model interface, Mock can be replaced with OpenAI/HuggingFace), BaseVectorStore (vector storage interface, reserved for pgvector/Milvus), BaseReranker (reranking interface), and BaseTool (tool call abstraction like SearchDocsTool). Data models are defined with SQLAlchemy, compatible with PostgreSQL (pgvector reserved design) and SQLite: vector fields use ordinary arrays for easy migration, independent tracking tables support observability, and JSONB metadata fields store unstructured information.

Agent implementation uses an explicit state machine pattern (reserved for LangGraph integration), with core nodes including retrieval planning (analyze query intent), evidence retrieval (obtain document fragments), evidence verification (check relevance and completeness), answer generation (with references), and tool decision (judge whether to call external tools). For security, all action tools only generate drafts (e.g., GitHub Issue), requiring manual review before execution to avoid unsafe side effects.

ContextForge plans a path from skeleton to full platform: short-term goals (support multi-data source ingestion, integrate real embedding and async queues, add pgvector search); mid-term goals (hybrid search fusion, query rewriting/metadata filtering/reranking, migrate to LangGraph with checkpoint/streaming/interruption support); long-term vision (regression-driven platform, establish a complete system of retrieval metrics like Recall@k, generation metrics like faithfulness, and Agent metrics like task completion rate).

ContextForge provides key insights for production RAG teams: 1. Architecture first (define interface boundaries first, Mock implementations maintain flexibility); 2. Observability built-in (tracking tables as part of core data models); 3. Secure by default (tools generate drafts instead of direct execution); 4. Progressive complexity (gradually introduce frameworks like LangGraph from simple sequential execution).

ContextForge represents a new approach to RAG system engineering, going beyond demo-level implementations to pursue maintainable, scalable, and evaluable production-grade architecture. For RAG teams migrating from prototype to production, this project provides valuable architectural references and implementation starting points.