The best-benchmarked open-source AI memory system. And it's free.
MemPalace is a local-first MCP server that gives Claude persistent, searchable memory by storing conversation history and project files as verbatim text rather than summaries or paraphrases. It connects to Claude Code and other MCP-compatible clients via stdio, wiring in through a standard JSON-RPC server configuration. The index organizes content into a hierarchical structure of wings (people or projects), rooms (topics), and drawers (original content), enabling scoped semantic search rather than flat-corpus retrieval. The default storage backend is ChromaDB, with additional options for SQLite exact-vector checks, Qdrant (REST), and Postgres with pgvector, all swappable through a common interface defined in `mempalace/backends/base.py`. A standout benchmark result is 96.6% R@5 on LongMemEval with no external API calls, meaning all embedding and retrieval runs entirely on the local machine. The CLI supports mining both project files and Claude Code session directories, and Docker images with optional GPU acceleration via CUDA are also available. Developers and researchers who need reproducible, private conversation context across sessions are the primary audience.
- ✓Open-source license (MIT)
- ✓Actively maintained (<30d)
- ✓Healthy fork ratio
- ✓Clear description
- ✓Topics declared
- ✓Documented (README)
claude mcp add mempalace -- npx -y skills{
"mcpServers": {
"mempalace": {
"command": "npx",
"args": ["-y", "skills"]
}
}
}MCP Servers overview
<div align="center">
<img src="assets/mempalace_logo.png" alt="MemPalace" width="240">
# MemPalace
Local-first AI memory. Verbatim storage, pluggable backend, 96.6% R@5 raw on LongMemEval — zero API calls.
[![][version-shield]][release-link]
[![][python-shield]][python-link]
[![][license-shield]][license-link]
[![][discord-shield]][discord-link]
</div>
> [!CAUTION]
> **Beware of impostor sites.** MemPalace has no other official websites. The **only** official sources are this **[GitHub repository](https://github.com/MemPalace/mempalace)**, the **[PyPI package](https://pypi.org/project/mempalace/)**, and the docs at **[mempalaceofficial.com](https://mempalaceofficial.com)**. Any other domain (including `.tech`, `.net`, or other `.com` variants) is an impostor and may distribute malware. Details and timeline: [docs/HISTORY.md](docs/HISTORY.md).
> [!IMPORTANT]
> **Claude Code sessions expire in 30 days without auto-save hooks wired.** [Read this →](https://github.com/MemPalace/mempalace/discussions/1388)
>
> Need the shortest recovery/setup path? Use the [Claude Code retention setup checklist](https://mempalaceofficial.com/guide/claude-code-retention.html).
---
## What it is
MemPalace stores your conversation history as verbatim text and retrieves
it with semantic search. It does not summarize, extract, or paraphrase.
The index is structured — people and projects become *wings*, topics
become *rooms*, and original content lives in *drawers* — so searches
can be scoped rather than run against a flat corpus.
The retrieval layer is pluggable. The current default is ChromaDB; the
interface is defined in [`mempalace/backends/base.py`](mempalace/backends/base.py)
and alternative backends can be dropped in without touching the rest of
the system.
Nothing leaves your machine unless you opt in.
Architecture, concepts, and mining flows:
[mempalaceofficial.com/concepts/the-palace](https://mempalaceofficial.com/concepts/the-palace.html).
---
## Install
### Agent-guided setup
Install the MemPalace skills first, then ask your coding agent to set up
MemPalace. The setup skill detects your system, installs the Python package,
configures MCP, and asks whether you want a private local palace, a shared-brain
hub, or a client connected to an existing hub:
```bash
npx skills add MemPalace/mempalace
```
The repository exposes three skills: `mempalace` for guided installation and
operations, `mempalace-recall` for search-before-answer recall, and
`mempalace-task` for logstream delegation. Installing a skill does not by
itself install the MemPalace CLI or MCP server; the setup skill guides the
agent through those system changes and verifies the live connection.
During guided setup the agent can offer weekly stable-release checks. They are
disabled by default, contact only PyPI when enabled, and never install updates
automatically. Cached availability appears in scoped `mempalace_status` fields
for the serving runtime and, when a local proxy is present, its client runtime,
allowing the agent to explain the release and request authorization before showing an exact
upgrade plan. Setup records whether the runtime came from `uv tool`, `pipx`, or
`pip` so the plan never proposes an upgrade command for the wrong installation.
### Direct CLI setup
MemPalace ships a CLI, so install it in an isolated environment to avoid
PEP 668 errors on Debian/Ubuntu/Homebrew Pythons and to keep mempalace's
deps (`chromadb`, `numpy`, `grpcio`, …) from conflicting with anything
else in your global site-packages.
We recommend [`uv`](https://docs.astral.sh/uv/) — `uv tool install` puts
the `mempalace` CLI in an isolated environment on your PATH:
```bash
uv tool install mempalace
mempalace init ~/projects/myapp
```
[`pipx`](https://pipx.pypa.io/) works the same way if you prefer it:
`pipx install mempalace`.
Prefer plain `pip` only inside an activated virtualenv where you
explicitly want `import mempalace` available:
```bash
python -m venv .venv && source .venv/bin/activate
pip install mempalace
```
### Android / Termux
Native Termux installation is not currently supported because compiled
dependencies such as ChromaDB and ONNX Runtime publish Linux wheels, not
Android wheels. Android ARM64 users can run the regular Linux packages in an
isolated Debian PRoot container instead. See the
[Termux installation guide](website/guide/termux.md) for the tested setup and
an argv-preserving launcher.
### Docker
A container image is also available for running the MCP server or the CLI
without a local Python toolchain. Multi-arch (amd64 + arm64), so it runs
natively on Apple Silicon:
```bash
docker pull ghcr.io/mempalace/mempalace:latest
```
Everything persists under `/data` — palace, config, and the cached embedding
model — so mount a volume there and reuse it across runs:
```bash
# MCP server over stdio — note the `-i` flag (JSON-RPC needs stdin)
docker run -i --rm -v mempalace-data:/data ghcr.io/mempalace/mempalace
# Run any CLI command instead. The container only sees what you mount, so
# mount the directory you want to mine — read-only is enough, mining never
# writes to the source.
docker run --rm -v mempalace-data:/data -v /path/to/project:/work:ro \
ghcr.io/mempalace/mempalace mine /work
docker run --rm -v mempalace-data:/data ghcr.io/mempalace/mempalace search "why GraphQL"
```
The first command that needs embeddings downloads the model into `/data`
(~80 MB for the default `minilm`, ~300 MB for `embeddinggemma`). It is a
one-off as long as the volume persists, but it does mean the first call is
slow and needs network — worth knowing before assuming a hung container.
Wire it into an MCP client (e.g. Claude Code) as a stdio server. Mount
anything you want the server to be able to mine — it cannot reach your
transcripts otherwise:
```json
{
"mcpServers": {
"mempalace": {
"command": "docker",
"args": [
"run", "-i", "--rm",
"-v", "mempalace-data:/data",
"-v", "/absolute/path/to/.claude/projects:/transcripts:ro",
"ghcr.io/mempalace/mempalace"
]
}
}
}
```
Use a real absolute path there — `~` and `$HOME` are not expanded by every
MCP client. Paths are container paths from then on: mine `/transcripts`, not
`~/.claude/projects`.
**Mount permissions on Linux.** The image runs as uid 1000 and bind mounts
keep their host ownership, so a mounted directory has to be readable by that
uid — an ordinary `0755` checkout is fine, a `0700` directory is not, and the
failure surfaces as `PermissionError: [Errno 13]` rather than anything about
Docker. Docker Desktop maps uids on macOS and Windows, so this only bites on
Linux. Do **not** work around it with `--user`: `/data` is owned by uid 1000
inside the image, so another uid cannot write the palace at all.
`docker compose run --rm mcp` works too (see `docker-compose.yml`), and
`deploy/docker-compose.server.yml` stands up the team server. To build the
image yourself instead of pulling — required for the GPU variant, which is not
published:
```bash
docker build -t mempalace . # CPU
docker build --build-arg EXTRAS="extract,spellcheck" -t mempalace .
docker build -f Dockerfile.gpu -t mempalace:gpu . # CUDA; run with --gpus all
```
The GPU image is x86_64-only: `onnxruntime-gpu` publishes no aarch64 Linux
wheels, so that last build fails on an ARM host (including Apple Silicon) with
a dependency-resolution error rather than an obvious one.
Note that a build from a clone uses whatever branch you checked out; `develop`
is the default branch, so pull the published image if you want the released
version.
## Storage backends
ChromaDB is the default and needs no configuration. MemPalace also ships a
pluggable backend contract, exercised across deliberately different substrates
so the contract is never accidentally shaped around one vendor. Every
non-default backend is opt-in.
| Backend | Mode | Install | Namespaces | Lexical | Configure with |
| ------- | ---- | ------- | :--------: | :-----: | -------------- |
| `chroma` _(default)_ | Local (embedded) | bundled | – | ✓ | – |
| `sqlite_exact` | Local (exact NumPy) | bundled | – | ✓ | – |
| `rust_exact` | Local (native vectors) | wheel / compiled | – | ✓ | – |
| `milvus` | Local (Lite) · Server opt-in | `mempalace[milvus]` | ✓ | ✓ | `MEMPALACE_MILVUS_URI` |
| `qdrant` | Server (REST) | bundled | ✓ | ✓ | `MEMPALACE_QDRANT_URL` |
| `pgvector` | Server (Postgres) | `mempalace[pgvector]` | ✓ | ✓ | `MEMPALACE_PGVECTOR_DSN` |
Select with `--backend <name>`, `MEMPALACE_BACKEND=<name>`, or
`"backend": "<name>"` in `config.json`. `rust_exact` uses the exact same `sqlite_exact.sqlite3` file on disk as `sqlite_exact` with zero data migration. See [native installation and vector CLI usage](crates/README.md) for the separately distributed wheel and executables.
### Vector Search Engine Performance
Initial Windows benchmarks of `rust_exact` and `mempalace-native` showed reduced memory usage and faster vector scans. These historical measurements span 168k and 334k-row workloads in a 1.75 GB database; they have not been rerun after the correctness fixes:
| Engine / Runtime | RSS Memory (334k items) | Query Latency (Warm p50) | Dependencies / Footprint |
| ---------------- | ----------------------- | ------------------------ | ------------------------ |
| `sqlite_exact` (Python + NumPy) | 2,430 MB | 14.7 ms | Python virtualenv |
| `rust_exact` (PyO3 + Rust engine) | **557 MB (-77%)** | **7.2 ms – 11.8 ms** | Python + native extension |
| `mempalace-native` (Standalone CLI) | **526 MB (-78%)** | **6.1 ms – 11.6 ms** | **Standalone executable (no Python)** |
See [`crates/`](crates/) for the core workspace, PyO3 bindings, and native CLI.
## Quickstart
```bash
# Mine content into the palace
mempalace mine ~/projects/myapp # project files
mempalace mine ~/.claude/projects/ --mode convos # Claude Code sessions (scope with --wing per project)
#What people ask about mempalace
What is MemPalace/mempalace?
+
MemPalace/mempalace is mcp servers for the Claude AI ecosystem. The best-benchmarked open-source AI memory system. And it's free. It has 59k GitHub stars and its last recorded update is dated 2026-09-08.
How do I install mempalace?
+
You can install mempalace by cloning the repository (https://github.com/MemPalace/mempalace) or following the README instructions on GitHub. ClaudeWave also provides quick install blocks on this page.
Is MemPalace/mempalace safe to use?
+
Our security agent has analyzed MemPalace/mempalace and assigned a Trust Score of 100/100 (tier: Verified). See the full breakdown of passed checks and flags on this page.
Who maintains MemPalace/mempalace?
+
MemPalace/mempalace is maintained by MemPalace. The last recorded GitHub activity is dated 2026-09-08, with 787 open issues.
Are there alternatives to mempalace?
+
Yes. On ClaudeWave you can browse similar mcp servers at /categories/mcp, sorted by popularity or recent activity.
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