langchain-rag-wiki 0.2.2

LangChain-compatible hybrid knowledge base retrieval with user-curated personal KB layer

langchain-rag-wiki

RAG meets wiki-style provenance.
Surfaces documents, learns from usage, and lets users build personal knowledge bases on top of shared vector stores.

Installation · Quickstart · How It Works · Real Vector DB Setup · Configuration · Contributing

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What Is This?

Standard RAG is stateless — every query hits the vector database fresh, returns probabilistic results, and forgets what was useful last time.

langchain-rag-wiki wraps any LangChain retriever and adds a personal knowledge layer on top:

• Documents retrieved repeatedly get suggested for saving after a configurable threshold
• Once saved, their chunks are searched semantically using cosine similarity — no external infrastructure, just numpy
• Every response shows a provenance block so you always know which document was used and from where
• A decay model keeps the cache honest — stale documents fade out automatically, and docs that consistently miss queries get demoted immediately

It's a drop-in BaseRetriever. Any LangChain chain, agent, or RAG pipeline that accepts a retriever works with it immediately.

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Installation

pip install langchain-rag-wiki

With optional backends:

pip install 'langchain-rag-wiki[sqlite]'     # SQLite persistent store
pip install 'langchain-rag-wiki[redis]'       # Redis distributed store
pip install 'langchain-rag-wiki[scheduler]'   # APScheduler decay jobs
pip install 'langchain-rag-wiki[llama]'       # LlamaIndex adapter
pip install 'langchain-rag-wiki[dev]'         # all of the above + pytest + fakeredis

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Quickstart

Zero infrastructure — uses in-memory state. No API keys needed.

from rag_wiki import RagWikiRetriever, RagWikiRetrieverConfig, MemoryStateStore

retriever = RagWikiRetriever(
    user_id          = "user-123",
    global_retriever = your_existing_retriever,  # any LangChain BaseRetriever
    state_store      = MemoryStateStore(),
    config           = RagWikiRetrieverConfig(fetch_threshold=3),
)

docs = retriever.invoke("quarterly earnings report")
print(retriever.last_provenance.render())  # see what was retrieved and from where

Run the bundled demo (no API keys, no services required):

python example.py

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How It Works

Retrieval Flow

Every query goes through two stages:

1. Semantic cache search  → PINNED + CLAIMED docs searched via cosine similarity
                            (keyword fallback if no embedding model available)
2. Global RAG fallback    → your existing vector retriever

Chunk vectors are accumulated upon user claim — when a user accepts a suggestion, the full document is automatically chunked, embedded, and stored in the local cache. From then on, it can be searched semantically without hitting the global DB.

Document Lifecycle

Documents move through six states based on usage patterns:

GLOBAL → SURFACED → SUGGESTED → CLAIMED → PINNED
                ↘               ↙
                  DEMOTED ──────

State	What it means	Retrieval path
GLOBAL	In the shared vector DB only	Vector similarity search
SURFACED	Retrieved at least once; counter is active	Vector search (counter increments)
SUGGESTED	Fetch count ≥ threshold; user prompted	Vector search (pending decision)
CLAIMED	User saved it; chunks in local cache	Semantic chunk search
PINNED	Consistently relevant; auto-promoted	Semantic chunk search (always included)
DEMOTED	Usage dropped or cache misses exceeded; evicted	Returns to vector search

Semantic Cache Search

When a document is CLAIMED or PINNED, its chunks are searched using proper cosine similarity:

# Embed query once, reused across all cached docs
query_vec = embedding_model.embed_query(query)

# For each cached doc: score all chunks, inject top-k above threshold
scores = cosine_similarity(query_vec, chunk_matrix)
top_chunks = chunks[scores >= similarity_threshold][:local_top_k]

Vectors are always normalised before the dot product, so scores are in [-1, 1] regardless of the embedding model's output magnitude.

The embedding model is resolved automatically — if your global retriever has an embeddings attribute, it's reused. You can also pass one explicitly. If neither is available, the system falls back to keyword matching silently.

Auto-Demotion

If a cached document's chunks consistently fail the similarity check across max_cache_miss_streak consecutive queries, it is demoted immediately — no need to wait for the daily decay job. Its chunk index is deleted and it returns to the global vector search pool.

Threshold and Suggestion

The save suggestion fires when a document has been retrieved fetch_threshold times. If the user declines, the next suggestion is scheduled at fetch_count + threshold × 2 — doubling the gap each time. The reset_threshold setting resets the fetch count if the document hasn't appeared in that many consecutive queries.

Decay Model

A background job recomputes each document's relevance score daily:

decay_score = weighted_avg(
    recency_factor   = exp(-λ × days_since_last_fetch),   weight: 0.40
    frequency_factor = min(fetch_count / freq_cap, 1.0),  weight: 0.30
    explicit_signal  = thumbs_up / thumbs_down value,     weight: 0.20
    chunk_hit_rate   = fraction of chunks ever matched,   weight: 0.15
)

Documents above pin_threshold (0.85) get auto-pinned after pin_hold_days. Documents below demotion_threshold (0.15) get evicted after demotion_hold_days.

Provenance Block

After every query, retriever.last_provenance.render() outputs:

────────────────────────────────────────────────────────────
📄 Sources used in this response
  • Kubernetes Pod Basics [from your KB]
    Chunks 0, 2  |  Saved to your KB
  • Docker Image Guide
    Full document  |  SURFACED (fetched 2×)

💡 "Docker Image Guide" has appeared in your queries 3 times.
   Would you like to save it to your personal knowledge base?
────────────────────────────────────────────────────────────

Also available as a structured dict via retriever.last_provenance.to_dict().

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Connecting to a Real Vector DB

Ingesting Documents

Use the included ingest.py as a starting point. It loads .txt files, splits them into chunks, injects the required metadata, and stores them in Chroma using Ollama embeddings:

python ingest.py

The metadata fields doc_id, doc_title, and doc_path on each chunk connect the vector store to the lifecycle tracking system. Without them, fetch counting and cache promotion won't work.

Chroma + Ollama (fully local, no API key)

The embedding model is auto-resolved from the Chroma vectorstore — no need to pass it separately.

from langchain_chroma import Chroma
from langchain_ollama import OllamaEmbeddings
from rag_wiki import RagWikiRetriever, RagWikiRetrieverConfig
from rag_wiki.storage.sqlite import SQLiteStateStore
import os

os.makedirs("wiki/documents", exist_ok=True)

vectorstore = Chroma(
    collection_name    = "my_docs",
    embedding_function = OllamaEmbeddings(model="nomic-embed-text:latest"),
    persist_directory  = "./chroma_db",
)

retriever = RagWikiRetriever(
    user_id          = "user-1",
    global_retriever = vectorstore.as_retriever(search_kwargs={"k": 5}),
    state_store      = SQLiteStateStore("sqlite:///./wiki/rag_wiki_state.db"),
    config           = RagWikiRetrieverConfig(
        fetch_threshold      = 3,
        similarity_threshold = 0.75,
        wiki_save_dir        = "wiki/documents",
    ),
)

docs = retriever.invoke("your query here")
print(retriever.last_provenance.render())

Passing an Embedding Model Explicitly

If your retriever doesn't expose an embeddings attribute, pass the model directly:

from langchain_openai import OpenAIEmbeddings

retriever = RagWikiRetriever(
    user_id          = "user-1",
    global_retriever = your_retriever,
    embedding_model  = OpenAIEmbeddings(),
)

Pinecone

from langchain_pinecone import PineconeVectorStore
from langchain_openai import OpenAIEmbeddings
from rag_wiki import RagWikiRetriever, MemoryStateStore

vectorstore = PineconeVectorStore(
    index_name = "my-index",
    embedding  = OpenAIEmbeddings(),
)

retriever = RagWikiRetriever(
    user_id          = "user-1",
    global_retriever = vectorstore.as_retriever(search_kwargs={"k": 5}),
    state_store      = MemoryStateStore(),
)

---

User Actions

# Save document to personal KB (chunks already accumulated at retrieval time)
retriever.accept_suggestion(doc_id="doc-1")

# Decline — next suggestion scheduled at escalating interval
retriever.decline_suggestion(doc_id="doc-1")

# Explicit positive signal — boosts decay score
retriever.thumbs_up(doc_id="doc-1")

# Explicit negative signal — reduces decay score
retriever.thumbs_down(doc_id="doc-1")

# Always include this document in every query context
retriever.force_pin(doc_id="doc-1")

# Remove from personal KB entirely (also deletes chunk index)
retriever.force_remove(doc_id="doc-1")

---

Configuration

RagWikiRetrieverConfig

Parameter	Type	Default	Description
fetch_threshold	int	3	Fetch count before save suggestion fires
reset_threshold	int	3	Queries without a hit before fetch count resets
similarity_threshold	float	0.75	Cosine similarity cutoff for cache chunk hits
local_top_k	int	3	Max chunks to inject per cached doc per query
wiki_save_dir	str | None	None	Directory to save accepted doc copies; None disables
no_resiluggest_days	int	30	Deprecated — kept for API compatibility
decay	DecayConfig	(see below)	Decay engine settings

DecayConfig

Parameter	Type	Default	Description
w_recency	float	0.40	Weight for recency in decay score
w_frequency	float	0.30	Weight for frequency
w_explicit	float	0.20	Weight for explicit user signals
w_chunk_hit	float	0.15	Weight for chunk hit rate
max_cache_miss_streak	int	10	Consecutive cache misses before immediate demotion
decay_lambda	float	0.05	Decay steepness λ (half-life ≈ 14 days)
freq_cap	int	20	Max fetch count for frequency normalisation
pin_threshold	float	0.85	Score above which doc is auto-pinned
demotion_threshold	float	0.15	Score below which doc is auto-demoted
pin_hold_days	int	7	Days score must hold above threshold before pin fires
demotion_hold_days	int	3	Days score must hold below threshold before demotion fires

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Storage Backends

Memory (default, zero dependencies)

from rag_wiki import MemoryStateStore
store = MemoryStateStore()

Thread-safe dict. Data lost on process restart. Best for development and testing.

SQLite (single-node persistent)

from rag_wiki.storage.sqlite import SQLiteStateStore
store = SQLiteStateStore("sqlite:///./wiki/rag_wiki_state.db")

Persists to a local file. Good for single-server production deployments.

Redis (distributed)

import redis
from rag_wiki.storage.redis_store import RedisStateStore

client = redis.Redis(host="localhost", port=6379, db=0)
store = RedisStateStore(client)

Required when running multiple API workers or load-balancing. Uses Redis hashes and sets for fast state queries.

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Decay Scheduler

from rag_wiki import DecayEngine, DecayConfig, MemoryStateStore
from rag_wiki.lifecycle.state_machine import StateMachine
from rag_wiki.scheduler import DecayScheduler

store     = MemoryStateStore()
engine    = DecayEngine(store, StateMachine(), config=DecayConfig())
scheduler = DecayScheduler(engine, store, backend="simple", interval_hours=24)

scheduler.start()
scheduler.run_now("user-123")   # manual trigger for one user
scheduler.run_all_users()       # all users with CLAIMED or PINNED docs
scheduler.stop()

Use backend="apscheduler" for production (requires pip install 'langchain-rag-wiki[scheduler]').

---

LlamaIndex Adapter

from llama_index.core import VectorStoreIndex
from rag_wiki.adapters.llamaindex import LlamaIndexRetrieverAdapter
from rag_wiki import RagWikiRetriever

adapter = LlamaIndexRetrieverAdapter(
    llama_retriever=index.as_retriever(similarity_top_k=5)
)

retriever = RagWikiRetriever(
    user_id          = "user-1",
    global_retriever = adapter,
)

Requires pip install 'langchain-rag-wiki[llama]'.

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Running Tests

pip install 'langchain-rag-wiki[dev]'
pytest tests/ -v

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Project Structure

rag_wiki/
├── __init__.py              # public exports
├── retriever.py             # RagWikiRetriever — main entry point
├── scheduler.py             # DecayScheduler (simple + APScheduler backends)
├── storage/
│   ├── base.py              # StateStore ABC + UserDocRecord + DocumentState
│   ├── chunk_store.py       # ChunkStore — chunk-level vector cache (disk + memory)
│   ├── memory.py            # MemoryStateStore (default, zero deps)
│   ├── sqlite.py            # SQLiteStateStore
│   └── redis_store.py       # RedisStateStore
├── lifecycle/
│   ├── state_machine.py     # pure transition logic
│   ├── fetch_counter.py     # threshold tracking + suggestion events
│   └── decay_engine.py      # scoring + pin/demotion transitions
├── transparency/
│   └── provenance.py        # ProvenanceBlock + ProvenanceBuilder
└── adapters/
    └── llamaindex.py        # LlamaIndex → LangChain adapter

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Contributing

Contributions are very welcome. See CONTRIBUTING.md for the full guide.

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License

MIT