lore-engine-poc

Proof of concept for the Lore Engine v1.1 architecture.

Five-minute goal: prove that with mock data, we can run a multi-database backend (Neo4j for the world graph, Postgres for operational records, MinIO for blob/image storage) and expose it all through a plugin-driven MCP gateway — where adding a new domain type is a new file in plugins/, not a Go change.

What's running

Container	Image	Port	Role
lore-neo4j	neo4j:5.26-community	7474 (browser), 7687 (bolt)	The world graph: people, factions, eras, events, lineage, time-bounded relations
lore-postgres	pgvector/pgvector:pg16	5432	Trade log, image manifests, audit, image embeddings
lore-minio	minio/minio:latest	9000 (S3), 9001 (console)	Image blob storage
lore-gateway	built locally	8765 (MCP JSON-RPC)	The plugin-driven gateway

The five plugins (this is the proof)

plugins/
├── world.py       # entity_context, was_true_at, state_at   (Neo4j)
├── lineage.py     # ancestors_of, descendants_of, lineage_of (Neo4j)
├── trade.py       # log_trade, trades_by_buyer, market_price (Postgres)
├── images.py      # register_image, recall_images, search_images_by_caption
│                  #                                          (MinIO + Postgres + Neo4j)
├── embeddings.py  # embed_images, search_images_semantic    (Postgres + pgvector)
└── consistency.py # find_contradictions, find_anachronisms, find_orphans,
                   # find_ontology_violations                (Neo4j)

The gateway also exposes one admin tool for the world namespace: list_worlds.

Tool counts and plugin membership are reported live by the gateway itself — curl -s http://localhost:8765/healthz returns the canonical list. As of v2 the healthz reports 19 tools across the 5 plugins above. See docs/LLM_CONSUMER_DEMO.md for an end-to-end driver that exercises them.

Each plugin is a single file with a register(registry) entry point. The gateway auto-loads every .py file in plugins/ at startup. No server.py change needed to add a new tool — drop a new file in, restart the container, the new tools appear in tools/list.

How to run it

cd /root/lore-engine-poc
docker compose up -d --build
# wait ~30s for neo4j + postgres + minio to be ready
docker exec -i lore-neo4j cypher-shell -u neo4j -p lore-dev-password < neo4j/init.cypher
docker compose exec -T postgres psql -U lore -d lore < postgres/init.sql
python3 seed.py
# gateway is now live on :8765

The seed.py script is idempotent (uses MERGE and ON CONFLICT). It loads:

• 3 eras (1st Age, 2nd Age, Age of Iron)
• 10 people (Theron, Maric, Aldric, Elara, Cael, Yssa, Vex, Alessia, Kael, Guildmaster Torren)
• 3 factions (House Vyr, The Crimson Pact, Merchants Guild)
• 4 locations (Valdorn, Mardsville, Thornwall Keep, Black Spire Pass)
• 4 items (Sword of Eventide, The Pale Ledger, Ruby Eye of Kael, Elara's Locket)
• 6 events
• 1 lineage group
• ~20 time-bounded relations
• 3 trade log entries
• 4 generated images (portraits + landscape + battle scene) uploaded to MinIO
• 5 hand-crafted consistency violations pre-materialized as :Contradiction, :Anachronism, :Orphan, and :OntologyViolation nodes (see docs/CONSISTENCY_DEMO.md)
• 1 parallel world, arda_greyscale — a minimal mirror of the default world with no overlapping node ids (see docs/MULTI_WORLD_DEMO.md)

Try the gateway

List all tools

curl -s -X POST http://localhost:8765/mcp \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}' | python3 -m json.tool

Look up Aldric

curl -s -X POST http://localhost:8765/mcp \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc":"2.0","id":1,"method":"tools/call",
    "params":{"name":"entity_context","arguments":{"name":"Aldric Raventhorne"}}
  }' | python3 -m json.tool

Time-bounded query: was House Vyr allied with the Merchants Guild in 230 TA?

curl -s -X POST http://localhost:8765/mcp \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc":"2.0","id":1,"method":"tools/call",
    "params":{
      "name":"was_true_at",
      "arguments":{
        "relation":"ALLIED_WITH",
        "subject":"House Vyr",
        "object":"Merchants Guild",
        "at_time":"2nd_age.year_230"
      }
    }
  }' | python3 -m json.tool

Lineage: Aldric's ancestors

curl -s -X POST http://localhost:8765/mcp \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc":"2.0","id":1,"method":"tools/call",
    "params":{"name":"ancestors_of","arguments":{"person":"Aldric Raventhorne","generations":5}}
  }' | python3 -m json.tool

Image recall: show me pictures of Aldric

curl -s -X POST http://localhost:8765/mcp \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc":"2.0","id":1,"method":"tools/call",
    "params":{"name":"recall_images","arguments":{"entity_id":"aldric"}}
  }' | python3 -m json.tool

The response includes a presigned_url — a MinIO URL valid for 1 hour. The LLM (or the calling client) can fetch the actual PNG from there.

Search images by caption

curl -s -X POST http://localhost:8765/mcp \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc":"2.0","id":1,"method":"tools/call",
    "params":{"name":"search_images_by_caption","arguments":{"q":"aldric"}}
  }' | python3 -m json.tool

Semantic image search (pgvector)

The embeddings plugin encodes each image's caption into a 384-dim vector with a local sentence-transformer model (all-MiniLM-L6-v2) and stores it in Postgres via the pgvector extension. Queries are encoded the same way and ranked by cosine distance. Unlike search_images_by_caption, this works on natural-language descriptions and doesn't require keyword overlap.

curl -s -X POST http://localhost:8765/mcp \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc":"2.0","id":1,"method":"tools/call",
    "params":{"name":"search_images_semantic","arguments":{"q":"a noble lord with a scar"}}
  }' | python3 -m json.tool

Returns Aldric's portrait as the top match. Try "a sneaky thief in a hood" for Vex. The first call triggers a one-time ~80MB model download on the gateway host; subsequent calls are cached in ~/.cache/torch.

If you add new images via register_image, embeddings are computed in the background by a daemon thread on the gateway — no separate job queue needed. Re-running embed_images is a no-op for images that already have embeddings.

Market price for the Pale Ledger

curl -s -X POST http://localhost:8765/mcp \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc":"2.0","id":1,"method":"tools/call",
    "params":{"name":"market_price","arguments":{"item_id":"pale_ledger"}}
  }' | python3 -m json.tool

What this proves

1. The plugin boundary works. A new domain type (trade, images, embeddings, consistency) is a new file in plugins/. No change to server.py, no change to docker-compose, no new container. Restart the gateway and the new tools are live. The consistency plugin (added in v2.T5) is the most recent example — four violation-detection tools, all in one file.

2. Polyglot storage is real, not aspirational. Neo4j holds the typed world graph. Postgres holds the time-series operational data, image manifests, and the image_embedding vectors (pgvector). MinIO holds the image bytes. Each store does what it's good at; the gateway composes the answers.

3. Time is a first-class query primitive. was_true_at checks time-bounded edges with a single Cypher query — no LLM, no inference. Year-level precision works against the mock data (see 2nd_age.year_230 example above).

4. Image recall works. Images are stored in MinIO, linked to entities in Neo4j ((:Image)-[:DEPICTS]->(:Person)), and discoverable by entity id, by tag, by caption substring search, or by natural-language description via the search_images_semantic (pgvector) tool. Presigned URLs are generated on the fly.

5. The consistency engine is real. The four find_* tools query pre-materialized violation nodes in Neo4j and return structured {violations, count} envelopes — not booleans, not error strings. The seed.py:seed_violations step computes the violations from the same heuristics (overlapping MEMBER_OF windows, Person.born > event_year, orphan entities, and :OntologyRule-driven checks) so the math is visible in plain Python — not hidden in Cypher. See docs/CONSISTENCY_DEMO.md for the five hand-crafted violations the seed surfaces.

6. Multiple worlds live in one graph. Every world-scoped node and edge carries a world_id property, and the read tools accept a world_id argument (defaulting to "default"). The v2.T6 seed loads a parallel arda_greyscale world with no overlapping node ids, and list_worlds() returns both. See docs/MULTI_WORLD_DEMO.md for the worked example.

7. An LLM can drive the whole surface. examples/llm_consumer.py is a real driver that takes a natural-language question, calls the gateway's tools/list, picks the right tool(s), and answers in prose — all wired through the local LiteLLM proxy. 5 question types × 9 distinct tools exercised, all answers hand-verified against the seed. See docs/LLM_CONSUMER_DEMO.md and examples/REPORT.md.

8. The world is small but real. 10 people + 9 greyscale-world people, 6 events, 5 images (4 default + 1 greyscale), ~20 relations — enough to demonstrate the architecture end-to-end across two parallel worlds. Scaling is a separate problem; this is the proof of shape.

What's not in this POC

• No LLM in the loop at runtime — the LLM consumer is a separate example. The MCP gateway itself is a tool server; the LLM client (Claude, GPT, anything reachable via the LiteLLM proxy) is the consumer. This is intentional — the POC validates the data and tool layers, not the LLM reasoning. The reasoning harness is in the design docs (lore-engine/docs/07-reasoning-harness.md); examples/llm_consumer.py implements the v1.1 of that harness against the live gateway.

• No world-builder UI. Everything is curl and cypher-shell. The UI is a v3 feature.

• No reflective memory or behavior layer. The Stanford Generative Agents pattern (memory stream + reflection + planning) is a v3 borrow per the comparison in lore-engine/docs/16-comparison.md.

Shipped in v2

What was on the v1 "next steps" list, and what it became in v2:

• Implement the consistency detection rules behind the 4 stub tools (T5). Done — see plugins/consistency.py and docs/CONSISTENCY_DEMO.md. 4 tools, 5 violations surfaced from the seed.
• Add the embedding-based semantic search plugin (uses the Image.caption and any future Person.summary text). Done — see plugins/embeddings.py and docs/LLM_CONSUMER_DEMO.md. 384-dim MiniLM, pgvector cosine distance, background embedding on register_image.
• Add an LLM client that consumes the gateway with the reasoning harness system prompt and runs the 5 question types from the design. Done — see examples/llm_consumer.py and examples/REPORT.md. 5 questions, 9 distinct tools, all hand-verified against seed ground truth.
• v2 extras not on the v1 list: the multi-world namespace with the arda_greyscale parallel seed (T6); the :OntologyViolation rule-driven detection in addition to the original three classes (T5); and a fresh-clone smoke test (scripts/ci-smoke.sh) that exercises the gateway end-to-end from a clean state (T1).