Development Methods and Tech Stack for an AI English Writing Agent

An AI English writing agent is implemented through the collaboration of a multi-agent pipeline, and can be split into agents for outline and idea generation, grammar and spelling, discourse logic, style polishing, and evaluation and scoring, built on LangGraph or PydanticAI. The recommended tech stack is Python (FastAPI) paired with PydanticAI, LangGraph, and LlamaIndex; the main reasoning model can be DeepSeek-V3, Claude 3.5 Sonnet, or GPT-4o, with GPT-4o-mini and Qwen-Turbo for lightweight validation. The system also uses RAG to connect to authoritative corpora such as the Oxford and Longman dictionaries and the Academic Phrasebank, and sets up anti-hallucination and academic integrity guardrails.