Citadel

Name: Citadel
Author: yp3y5akh0v

by yp3y5akh0vversion 2.7.0i★ –iRuns on your computer

Registry namedev.citadeldb/mcp

Install

Overview

Description from the maker (original English)

Encrypted-first embedded database with vector search and agent memory, exposed as MCP tools

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi0 of 1 passedChecked from public information; code not scanned yet
UsageiNot measured yet★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Runs on your computer
Transport: stdio
Category: Search & AI memory
You need to fill in: CITADEL_KEY

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 0 of 1 passed
Runs on your computer with your user’s permissions (files, network, apps).
You fill in yourself: CITADEL_KEY

Values marked secret are keys to your account. Never share them or paste them into a chat.

You need

PyPIPython’s uv installed (for the uvx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

{
  "mcpServers": {
    "citadeldb": {
      "command": "uvx",
      "args": [
        "citadeldb-mcp",
        "--db",
        "your-value",
        "--embedder",
        "your-value"
      ],
      "env": {
        "CITADEL_KEY": "your-value"
      }
    }
  }
}

Run this in your terminal

claude mcp add citadeldb --env CITADEL_KEY=your-value -- uvx citadeldb-mcp --db your-value --embedder your-value

Fill in the empty values before running it.

This one needs values on its command line, so copy the settings and fill them in.

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "citadeldb": {
      "command": "uvx",
      "args": [
        "citadeldb-mcp",
        "--db",
        "your-value",
        "--embedder",
        "your-value"
      ],
      "env": {
        "CITADEL_KEY": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one needs values on its command line, so copy the settings and fill them in.

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "citadeldb": {
      "type": "stdio",
      "command": "uvx",
      "args": [
        "citadeldb-mcp",
        "--db",
        "your-value",
        "--embedder",
        "your-value"
      ],
      "env": {
        "CITADEL_KEY": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

Your choice stays on this device in a cookie; no account needed.

Values you fill in

CITADEL_KEY secret required env
Passphrase used to unlock the encrypted Citadel database

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 7, 2026

! Caution
Maker matches the repo
The publisher (citadeldb.dev) is not the repo owner (yp3y5akh0v); someone else may have listed it
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
– Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
– Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
… Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Search & AI memoryi

More stars than 0% of the other 7249 servers in this category
Published to the registry more recently than 49% of the other 7249 servers in this category
Basic checks equal to or better than 33% of the other 7249 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is Citadel safe?

It passed 0 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

You need to fill in: CITADEL_KEY

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed –, and the latest version (2.7.0) reached the registry 40 days ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Python (uv) on your computer.

What can I use instead?

In the same category: Context7, Codebase Memory, Exa

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Reading a card:★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi

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README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

citadeldb-mcp

mcp-name: dev.citadeldb/mcp

Model Context Protocol (MCP) server for the Citadel encrypted memory engine. Gives any MCP client (Claude Desktop, an IDE, an agent) persistent, encrypted memory.

Memory lives in a local citadeldb-mem region: AES-256 encrypted at rest, per-atom sealed and HMAC-authenticated, recalled through a hybrid vector + keyword + recency + importance fusion over a PRISM approximate nearest-neighbor index, connected by a typed edge graph, and forgotten by destroying keys (cryptographic erasure).

Install

Run it with no install. For semantic recall, pull the recommended embedder and cross-encoder reranker once, then enable both:

uvx citadeldb-mcp pull e5-large

uvx citadeldb-mcp pull ms-marco-minilm

The pull commands do not open a vault. Before serving, set CITADEL_KEY to the vault passphrase (export CITADEL_KEY="your-passphrase" on macOS/Linux or $env:CITADEL_KEY = "your-passphrase" in PowerShell), then run:

uvx citadeldb-mcp --db memory.cdl --embedder e5-large --reranker ms-marco-minilm

e5-large + ms-marco-minilm is the recommended semantic-recall setup. See the memory benchmarks for measured configurations. Models are never downloaded automatically.

Built-in pulls use release-pinned Hugging Face revisions. Each complete snapshot is verified against compiled sizes and SHA-256 digests, then stored with a BLAKE3 manifest under / / /. A flat cache created by an earlier CitadelDB release is not trusted; run pull again to create the pinned snapshot. --model-dir and --reranker-dir remain explicit bring-your-own-artifact paths and bypass the managed-cache manifest. Citadel treats those directories as user-trusted and does not attest their contents.

Or install the command with pip install citadeldb-mcp or cargo install citadeldb-mcp, then wire it into Claude Desktop (claude_desktop_config.json):

"mcpServers": { "citadel": { "command": "citadeldb-mcp", "args": ["--db", "/absolute/path/to/memory.cdl", "--embedder", "e5-large", "--reranker", "ms-marco-minilm"], "env": { "CITADEL_KEY": "your-passphrase" } } } }

The server supports stateless MCP 2026-07-28 discovery and per-request metadata, plus the initialize-based 2025-11-25 and 2025-06-18 revisions for existing clients.

Tools (over a bounded, cancellable JSON-RPC 2.0 stdio transport):

mem_recall - hybrid retrieval (vector + keyword + recency + importance); filter by kind/payload, expand along the memory graph, override fusion weights, and optionally attach provenance (derived_from), per-hit integrity verdicts (attest), and resource_links to each hit
mem_fetch - deterministic cursor-based listing of a kind (no embedding)
mem_get - bounded exact-id batch retrieval in request order, with missing atoms marked explicitly
mem_edges - cursor-based typed graph introspection
mem_profile - what the memory knows about a query: recall plus its graph neighborhood
mem_summarize - per-kind digest of a region
mem_verify - re-authenticate atoms off disk: per-atom integrity verdict (authentic / tampered / key_erased / missing / plaintext_unattested)
mem_remember - store one atom with optional provenance and retry-safe idempotency
mem_remember_batch - atomically store an ordered batch; every entry carries a distinct idempotency key, and a changed reuse rejects the whole batch
mem_update - replace a stored atom's payload in place (preserves id, edges, and embedding)
mem_link / mem_unlink - add or remove one exact typed edge
mem_evolve - recompute an atom's neighbor links and stored importance
mem_evict - selective forgetting by policy (cryptographic erasure on encrypted regions)
mem_forget - forget atoms by id and return a verifiable erasure receipt; optionally erase their region-local derived_from closure atomically (cryptographic erasure on encrypted regions; immutable atoms require the protected-erasure opt-in)

The citadeldb-mcp binary reads the passphrase from CITADEL_KEY and serves one region (encrypted by default); only protocol messages go to stdout, diagnostics to stderr. --region-mode plaintext disables per-atom encryption and cryptographic erasure for that region; the database remains encrypted at rest. Erasure does not revoke plaintext exports or keys retained in pre-erasure backups or snapshots.

Every server invocation must select an embedder. The CPU Candle embedder is compiled into the standalone server's default build, including the citadeldb-mcp Python package; it is not included in the default citadeldb library wheel. Models are fetched only on explicit pull.

Embedder pull names: e5-large (recommended), e5-large-v2, bge-small, bge-base, bge-large, minilm. Reranker: ms-marco-minilm. Or point --model-dir at a compatible local checkpoint for the selected catalog pipeline, and build with --features cuda-embed to run on an NVIDIA GPU.

This crate is part of the Citadel workspace.

License

Apache-2.0

Citadel

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

Values you fill in

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Search & AI memoryi

Common questions

Alternatives

Context7

Codebase Memory

Exa

README from the maker

citadeldb-mcp

Install

License