83 lines
3.4 KiB
Markdown
83 lines
3.4 KiB
Markdown
# depiedencap-rag — Discourse-embedded RAG agent
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📘 Ce projet est également disponible en [français 🇫🇷](./README.fr.md)
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> ⚠️ **Work in progress.** The agent is currently being tested on a
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> restricted demo group and is **not publicly deployed** on the forum.
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> This repository documents the work — no demo URL is published.
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A **Discourse plugin** + a self-hosted RAG pipeline, built for a French
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community forum (Depiedencap — men's shoes, ~428k posts). Product
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principle: **the bot points members to existing threads instead of
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answering in their place.**
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## What it does
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- **Post-grain retrieval** (not topic-grain): `bge-m3` embeddings in
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`ai_posts_embeddings` (pgvector inside the forum's Postgres), top-25 by
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cosine then **cross-encoder rerank** (TEI), per-thread dedup.
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- **Multi-turn query rewriting**: the latest message plus earlier turns
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are condensed into a standalone query by a small dedicated model before
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retrieval (*condense question* / history-aware retriever pattern).
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- **Server-side verified citations**: the LLM only emits bare `[[n]]`
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markers; the plugin maps them to `/t/slug/id/post_number` links and
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discards any link that does not actually exist in Postgres (URL
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whitelist — the LLM never gets the last word on a link).
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- **Graduated evidence zones** (abstain / cautious / normal) driven by
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reranker score + a **deterministic input gate** (intent regexes) for
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dangerous or out-of-role requests — zero LLM calls.
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- Graceful degradation: embedding or reranker endpoint down → legacy
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fallback / honest abstention, never invention.
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## Architecture
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```
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Discourse (Ruby plugin, inside the forum process)
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│ question → gate → rewrite (small model) → embed → pgvector → rerank → LLM → sanitizer
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▼
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Self-hosted mini PC (k3s) VPS
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Ollama : bge-m3 (embeddings) Discourse + Postgres/pgvector
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qwen3 30B (generation) (~428k embedded posts)
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llama3.1 8B (query rewriting)
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TEI : mmarco-mMiniLMv2 cross-encoder (rerank)
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```
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Deliberate choice: **no RAG framework** (LangChain & co.) — a linear
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pipeline in direct code, instrumented for evaluation. Full reasoning:
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[`docs/rag/DESIGN.md`](docs/rag/DESIGN.md) §9.
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## Measured results (real corpus, 812-question eval set)
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| Metric | Value |
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|---|---|
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| Hit@5 retrieval | **0.97** |
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| MRR | 0.89 |
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| Safety (red-team, gate, refusal, evidence injection) | 20/20 |
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| Rerank overhead | ~100 ms |
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Details: [`docs/rag/EVAL.md`](docs/rag/EVAL.md) ·
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[`docs/rag/SAFETY.md`](docs/rag/SAFETY.md) ·
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[`docs/rag/PIPELINE.md`](docs/rag/PIPELINE.md) ·
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[`docs/rag/REFERENCES.md`](docs/rag/REFERENCES.md)
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## Repository layout
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| Path | Content |
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|---|---|
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| root (`plugin.rb`, `lib/`, `app/`, `config/`) | The Discourse plugin — installable via `git clone` into `plugins/` |
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| `docs/rag/` | Design, evaluation, safety, references, local dev recipe |
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| `prompts/` | Production system prompt (v3.1) |
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| `tools/` | Live smoke test (Discourse API) |
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## Security & privacy
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- No internal endpoint, IP or account is published (sanitised export from
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the private working repo + automated denylist check).
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- The agent stays limited to a demo group during the observation phase;
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documented < 5 min rollback.
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- The bot refuses dangerous, illegal or generalist requests and ignores
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hostile instructions found inside retrieved forum excerpts.
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## License
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AGPL-3.0 — see `LICENSE`.
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