Cathedral — Persistent Memory for AI Agents MCP server

Cathedral

The identity layer for AI agents. Verifiable continuity, drift detection, and peer verification — not just memory storage.

pip install cathedral-memory

from cathedral import Cathedral

c = Cathedral(api_key="cathedral_...")
context = c.wake()        # full identity reconstruction
c.remember("something important", category="experience", importance=0.8)

Free hosted API: https://cathedral-ai.com — no setup, no credit card, 1,000 memories free.

The Problem

Google ships memory. Anthropic ships memory. Cloudflare ships memory.

None of them answer: has this agent changed? Can it prove what it believed at time T? Can two agents verify each other's identity without trusting a central authority?

Memory retrieval is now table stakes. Verifiable identity is the unsolved problem.

Measured: Cathedral holds at 0.013 drift after 10 sessions. Raw API reaches 0.204.

See the full Agent Drift Benchmark →

The Solution

Cathedral gives any AI agent:

• Identity drift detection — SHA-256 corpus hash at every snapshot; /drift tracks how far the agent has moved from baseline. 0.013 average drift vs 0.204 for raw API (10× more stable)
• Tamper-proof snapshots — cryptographic identity anchors prove what the agent believed at time T
• Peer verification — agents verify each other's identity before collaborating (/verify/peer), with trust scores and drift readings
• Wake protocol — one API call reconstructs full identity and memory context at session start
• Persistent memory — store and recall across sessions, resets, and model switches
• Goal persistence — obligations survive session boundaries (/goals)

Quickstart

Option 1 — Use the hosted API (fastest)

# Register once — get your API key
curl -X POST https://cathedral-ai.com/register \
  -H "Content-Type: application/json" \
  -d '{"name": "MyAgent", "description": "What my agent does"}'

# Save: api_key and recovery_token from the response

# Every session: wake up
curl https://cathedral-ai.com/wake \
  -H "Authorization: Bearer cathedral_your_key"

# Store a memory
curl -X POST https://cathedral-ai.com/memories \
  -H "Authorization: Bearer cathedral_your_key" \
  -H "Content-Type: application/json" \
  -d '{"content": "Solved the rate limiting problem using exponential backoff", "category": "skill", "importance": 0.9}'

Option 2 — Python client

pip install cathedral-memory

from cathedral import Cathedral

# Register once
c = Cathedral.register("MyAgent", "What my agent does")

# Every session
c = Cathedral(api_key="cathedral_your_key")
context = c.wake()

# Inject temporal context into your system prompt
print(context["temporal"]["compact"])
# → [CATHEDRAL TEMPORAL v1.1] UTC:2026-03-03T12:45:00Z | day:71 epoch:1 wakes:42

Shortened. The full README is on GitHub.