
Hindsight-MemPalace
β 10from holetron
Self-hosted long-term memory for AI agents: MCP server with hierarchical recall over pgvector.
Hindsight MemPalace
Hierarchical memory for AI agents. Storage + taxonomy in one system.
A hybrid of two open-source projects:
Project What it does What it lacks Hindsight by vectorize-io Long-term vector memory for AI agents. Stores, embeds, recalls. No structure β all memories in one flat pile MemPalace by milla-jovovich Hierarchical taxonomy: rooms, halls, layers β the method of loci for AI No storage engine β a spec without a database
This fork connects them. Hindsight's vector store + MemPalace's taxonomy = structured memory with semantic search.
How it works
ββββββββββββββββββββββββββββββββββββββββββββββββββββββββ
β MEMPALACE β
β β
β ββββ Room: auth βββ ββββ Room: pipeline βββ β
β β Hall: facts β β Hall: decisions β β
β β Hall: procedures β β Hall: events β β
β β Hall: warnings β β Hall: facts β β
β β β β β β
β β L0 ββββ always β β L0 ββββ always β β
β β L1 ββββ warm β β L1 ββββ warm β β
β β L2 ββββ cold β β L2 ββββ cold β β
β β L3 ββββ archive β β L3 ββββ archive β β
β ββββββββββββββββββββ βββββββββββββββββββββββ β
β β β β
β βββββ Tunnel βββββββββββ β
β (cross-bank bridge) β
β β
β Closets: compressed summaries + source pointers β
ββββββββββββββββββββββββ¬ββββββββββββββββββββββββββββββββ
β
Hindsight vector store
(embeddings + semantic search)
Rooms β topic isolation. Auth, pipeline, infrastructure, schema β each topic in its own room. An agent searching for auth facts won't wade through 500 deploy memories.
Halls β knowledge typing within a room. Fact, event, decision, procedure, warning. The system knows what it's looking at before reading β like Content-Type for memory.
Layers L0βL3 β four priority tiers. L0 (core) is always loaded. L3 (archive) is deep-search only. Same idea as CPU cache hierarchy: L1 is fast and small, RAM is slow but holds everything.
Closets β AI-compressed summaries with source pointers. Deduplication at the knowledge level: 10 related facts β 1 paragraph + references.
Tunnels β cross-bank bridges between agents. Agent A discovers an insight β Agent B sees it through a tunnel without data duplication.
Comparison
Hindsight MemPalace This fork What it is Long-term memory store Hierarchical taxonomy spec Storage + taxonomy hybrid Storage Vector store + embeddings None (spec only) Vector store + embeddings Memory structure Flat (all memories equal) Rooms β Halls β Layers Rooms β Halls β Layers + embeddings Retrieval Semantic search No retrieval engine Room-scoped semantic search Classification None Defined in spec Keyword-based, <1ms, zero LLM cost Priority tiers All memories equal L0βL3 (spec) L0βL3 (implemented) Compression None Closets (spec) Closets with source pointers Multi-agent Shared bank Tunnels (spec) Tunnels (cross-bank bridges) MCP integration API only None 5 tools via MCP protocol Setup Docker Manual config Docker (drop-in upgrade)
MCP Server
The mcp-server/ directory contains a standalone MCP server. Any MCP-compatible client (Claude Code, OpenClaw, Cursor, etc.) connects and gets structured long-term memory.
Tools
Tool Description
memory_retain Save a memory with automatic room/hall classification
memory_recall Scoped semantic search with room/hall/layer filters
memory_reflect Deep reasoning β synthesize facts, find patterns, answer with citations
memory_compress Create closet summaries from accumulated facts
memory_bridge Cross-bank tunnels between related memories
Setup
cd mcp-server
npm install
HINDSIGHT_URL=http://localhost:5100 node server.js
Claude Code config
Add to ~/.claude/mcp.json:
{
"mcpServers": {
"mempalace": {
"command": "node",
"args": ["/path/to/mcp-server/server.js"],
"env": {
"HINDSIGHT_URL": "http://localhost:5100",
"MEMPALACE_BANK": "my-agent-bank"
}
}
}
}
See mcp-server/README.md for full docs and environment variables.
API changes from upstream
The base /retain and /recall endpoints are fully backward-compatible. New parameters are optional.
New parameters
Endpoint Parameter Type Description
/retain room string Topic room (auto-classified if omitted)
/retain hall string Knowledge type (auto-classified if omitted)
/retain layer int Priority 0-3 (default: 2)
/recall room string Filter recall to a specific room
/recall hall string Filter recall to a specific hall
/recall max_layer int Maximum layer depth to search
New endpoints
Method Endpoint Description
POST /bridge Create a cross-bank memory bridge
GET /tunnels List existing tunnels
POST /tunnels Create a tunnel between banks
GET /closets List compressed memory summaries
POST /closets Compress L3 memories into a closet
Room/Hall taxonomy
Rooms (topics)
auth Β· pipeline Β· infrastructure Β· deployment Β· schema Β· api Β· ui Β· tax Β· hr Β· legal Β· compliance Β· monitoring Β· agent Β· general
Halls (knowledge types)
warning Β· decision Β· procedure Β· event Β· preference Β· discovery Β· fact
Layers
Layer Name Behavior L0 Critical Always recalled L1 Important Recalled by default L2 Normal Standard (default for new memories) L3 Archive Deep search only, compressed into closets
Auto-classification
MemPalace includes a keyword-based classifier (room_hall_classifier.py) that assigns room and hall automatically when not provided. No LLM call β classification is instant and free.
Extensible: add keywords to ROOM_KEYWORDS / HALL_KEYWORDS dictionaries.
Examples
Store a memory
curl -X POST http://localhost:5100/retain \
-H "Content-Type: application/json" \
-d '{
"bank": "project-alpha",
"text": "Never restart PROD PM2 without confirming DEV works first.",
"room": "deployment",
"hall": "warning",
"layer": 0
}'
Scoped recall
curl -X POST http://localhost:5100/recall \
-H "Content-Type: application/json" \
-d '{
"bank": "project-alpha",
"query": "deployment safety rules",
"room": "deployment",
"hall": "warning",
"max_layer": 1
}'
Cross-bank bridge
curl -X POST http://localhost:5100/bridge \
-H "Content-Type: application/json" \
-d '{
"source_bank": "project-alpha",
"target_bank": "project-beta",
"room": "infrastructure",
"hall": "procedure"
}'
What we changed
A taxonomy layer over Hindsight's vector store, plus a standalone MCP server.
Key additions:
-
room_hall_classifier.pyβ keyword-based taxonomy engine (new) -
aa1_add_room_hall_to_memory_units.pyβ DB migration: flat β hierarchical, adds room/hall +layercolumn (new) -
mcp-server/β standalone MCP server with 5 tools (new) -
Storage layer β room/hall/layer metadata on every write
-
Retrieval β room-scoped search with hall filtering
-
Compression β closet generation with source linking
-
Tunnels β cross-bank memory sharing protocol
Full architectural spec: MEMPALACE.md
Upstream compatibility
This fork tracks vectorize-io/hindsight as upstream. To pull updates:
git remote add upstream https://github.com/vectorize-io/hindsight.git
git fetch upstream
git merge upstream/main
All changes are additive β existing Hindsight behavior is preserved.
Credits
-
Hindsight by vectorize-io β the memory storage engine
-
MemPalace by milla-jovovich β the hierarchical taxonomy architecture
-
Holetron β fork maintainers, MCP server, integration
License
MIT β same as upstream Hindsight. See LICENSE.
cd mcp-server
npm install
HINDSIGHT_URL=http://localhost:5100 node server.jsBefore it works, you'll need: HINDSIGHT_URLMEMPALACE_BANK
Quick start
git clone https://github.com/holetron/hindsight-mempalace.git
cd hindsight-mempalace
cp .env.example .env
# edit .env with your config
docker compose -f docker-compose.mempalace.yml up -d
API available at http://localhost:5100. Drop-in replacement for vanilla Hindsight β same API, same clients, new brain.
Embeddings
Ships with BAAI/bge-small-en-v1.5 (384-dim) β fast, CPU-friendly, baked into the image so first run needs no network download. It's English-optimized; recall quality on other languages degrades.
For multilingual memory (e.g. RU, multi-script), point it at a multilingual model:
HINDSIGHT_API_EMBEDDINGS_LOCAL_MODEL=BAAI/bge-m3 # 1024-dim, multilingual
Dimension is detected automatically. β οΈ Switching models changes the vector dimension β do it on an empty memory store, or wipe + re-embed, since existing vectors can't be mixed across dimensions.
No common issues documented yet. If you hit a problem, the repository's GitHub Issues page is the best place to look.