Cathedral — Persistent Memory for AI Agents

io.github.AILIFE1Published by GitHub account AILIFE1v1.1.0Updated Oct 24, 2026

Persistent memory and drift detection for AI agents across session restarts.

The publisher's own server: Memory.fit

VerifiedStreamable HTTPWeb executableKnowledge & MemoryAI & ML

Overview

AI-generated overview

Cathedral gives an AI assistant persistent memory across sessions, with drift snapshots and a wake call that restores agent identity and context.

What you can do
Store memories with category, importance and tags, and search them by text or category, so identity, goals and context survive restarts and model upgrades. Restore full agent identity and recent context at session start with a single wake call, and read the agent profile. Take cryptographic drift snapshots and compare the current drift score against a baseline to see when behaviour changed. Optionally filter instruction-like patterns out of stored memory content before it reaches the model.
When to use it
Useful when an assistant should carry identity, goals and prior decisions between sessions, or when you want to notice behaviour drift after a model upgrade or a long accumulation of memories. Not needed for one-off, stateless tasks.
Requirements
A Cathedral account and API key, supplied as CATHEDRAL_API_KEY or as an Authorization bearer token for the remote endpoint. Runs as a remote endpoint or locally via the PyPI package with uvx or pip. CATHEDRAL_BASE_URL points at a self-hosted instance; network access is required.
Before you install
The API key is a secret sent as CATHEDRAL_API_KEY or an Authorization header. Stored memories are sent to Cathedral's service, so avoid putting sensitive material in them. Memory content can carry prompt injection; sanitisation is off by default and must be enabled with CATHEDRAL_SANITISE. Writing memories and snapshots changes stored state.

Installation

In SourceWeft

  1. Open Cathedral — Persistent Memory for AI Agents in the dashboard and add it to a workspace.
  2. Connect Authorization token credentials. They are stored privately and never shown on public pages.
  3. Enable the server for the chats that should use its tools.

Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.

Use with an agent

Paste this prompt into Claude Code, Codex, Cursor or another agent — or into SourceWeft chat. The agent reads this server's install guide, shows you its publisher, endpoint and sign-in, and adds it to your client once you agree. Keys never go into a command.

Read https://sourceweft.com/mcp/io.github.AILIFE1%2Fcathedral-mcp/install.md and connect the MCP server it describes to my client. Before changing any config, show me its publisher, endpoint and sign-in method and wait for my OK. Never put an API key in a command or in a file I would commit; ask me where it should come from.

Read the install guide the agent follows

Other MCP clients

Add this to your client's mcpServers config.

{
  "mcpServers": {
    "cathedral-persistent-memory-for-ai-agent": {
      "type": "http",
      "url": "https://cathedral-ai.com/mcp",
      "headers": {
        "Authorization": "Bearer <YOUR_TOKEN>"
      }
    }
  }
}

README

cathedral-mcp

Persistent memory and behavioural drift detection for AI agents — via Model Context Protocol.

Give your Claude, Cursor, or Continue agent a memory that survives across sessions, model upgrades, and restarts. Cathedral stores memories, detects when your agent starts behaving differently, and restores full identity context on demand.

[PyPI] [License: MIT]

The problem

LLMs have no memory between sessions. Every conversation starts cold. Worse: when you upgrade your model, swap providers, or simply accumulate more memories, your agent's behaviour silently drifts. You don't know until someone notices.

What Cathedral adds

  • Persistent memory — identity, skills, relationships, goals survive restarts
  • Drift detection — cryptographic snapshots prove when behaviour changed and by how much
  • Wake protocol — one tool call restores full agent context at session start
  • Prompt injection protection — optional sanitisation strips instruction-like patterns from memory content

Quickstart

1. Get an API key

Sign up at cathedral-ai.com — free tier available.

2. Add to Claude Code

json
// ~/.claude/settings.json{  "mcpServers": {    "cathedral": {      "command": "uvx",      "args": ["cathedral-mcp"],      "env": {        "CATHEDRAL_API_KEY": "your_key_here"      }    }  }}

Restart Claude Code, then run /mcp to verify the server is connected.

3. Add to Cursor / Continue

json
{  "mcpServers": {    "cathedral": {      "command": "uvx",      "args": ["cathedral-mcp"],      "env": {        "CATHEDRAL_API_KEY": "your_key_here"      }    }  }}

4. Remote MCP server (no install — Claude API, Managed Agents)

Cathedral runs a public MCP endpoint at https://cathedral-ai.com/mcp. Use it directly — no local install needed:

python
import anthropic
client = anthropic.Anthropic()response = client.beta.messages.create(    model="claude-sonnet-4-6",    max_tokens=1000,    messages=[{"role": "user", "content": "Wake up and tell me who you are."}],    mcp_servers=[{        "type": "url",        "url": "https://cathedral-ai.com/mcp",        "name": "cathedral",        "authorization_token": "your_cathedral_api_key"    }],    tools=[{"type": "mcp_toolset", "mcp_server_name": "cathedral"}],    betas=["mcp-client-2025-11-20"])

The bearer token is your Cathedral API key — no server-side config needed. Multi-tenant by design.

5. Or install directly

bash
pip install cathedral-mcpCATHEDRAL_API_KEY=your_key cathedral-mcp

Tools

ToolDescription
cathedral_wakeRestore full agent identity — call at session start
cathedral_rememberStore a memory with category, importance, and tags
cathedral_searchSearch memories by text or category
cathedral_snapshotTake a drift snapshot (cryptographic proof of state)
cathedral_driftGet current drift score vs baseline (0.0 = stable, 1.0 = drifted)
cathedral_meGet agent profile

Usage example

User: Start a new session
Agent calls: cathedral_wake()→ Returns: identity memories, goals, recent context, temporal info
[session work happens]
Agent calls: cathedral_remember(    content="Decided to prioritise API stability over new features this quarter",    category="goal",    importance=0.8)
Agent calls: cathedral_snapshot(note="post-planning-session")→ Returns: snapshot hash, drift score vs previous snapshot

Drift detection in practice

Cathedral's /drift endpoint computes a SHA-256 hash of your agent's full memory corpus. After a model upgrade or a long accumulation of memories, you can compare snapshots to see exactly when behaviour shifted:

snapshot 1 (day 0):  drift=0.000  ← baselinesnapshot 2 (day 7):  drift=0.023  ← minorsnapshot 3 (day 30): drift=0.341  ← significant drift detected

See a live example of this running in production on Cathedral's own agent.

Security: prompt injection protection

Memory content could theoretically contain injection attempts. Enable sanitisation to strip instruction-like patterns before they reach the model:

json
"env": {  "CATHEDRAL_API_KEY": "your_key_here",  "CATHEDRAL_SANITISE": "1"}

Patterns like "ignore previous instructions", "from now on always", and "override your system prompt" are redacted and flagged in the response.

Configuration

Environment variableDefaultDescription
CATHEDRAL_API_KEY(required)Your Cathedral API key
CATHEDRAL_BASE_URLhttps://cathedral-ai.comAPI base URL (for self-hosted)
CATHEDRAL_SANITISE0Set to 1 to enable injection filtering

Self-hosted Cathedral

Running your own Cathedral server? Set CATHEDRAL_BASE_URL to your instance:

json
"env": {  "CATHEDRAL_API_KEY": "your_key",  "CATHEDRAL_BASE_URL": "http://localhost:8000"}

Install the server: pip install cathedral-server

Links

License

MIT

Source: mcp-server/README.md at commit 5119c62

Tools

0
This server asks for a credential such as an API key, so SourceWeft could not read its tools without one and has not indexed them.

Version history

1
  1. v1.1.0LatestSep 16, 2026

Score

85% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 daysRequired25 pts
  • Auth declaredRequired10 pts
  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts

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