Memorycrystal

Persistent memory for AI agents. Every conversation remembered. Every decision recalled. Every session informed.

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Your AI forgets everything between sessions — who you are, what you decided, what failed, what works. Memory Crystal fixes that.

It captures conversations in real time, extracts durable knowledge, manages raw sensory retention, and injects the right context before every response. One install. No prompting gymnastics. Your AI just knows.

curl -fsSL https://memorycrystal.ai/crystal | bash

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Works with everything

Install Memory Crystal on any MCP-compatible AI tool in one command:

| Platform | Install | |---|---| | Claude Code | curl -fsSL https://memorycrystal.ai/install-claude-mcp.sh \| bash | | Codex CLI | curl -fsSL https://memorycrystal.ai/install-codex-mcp.sh \| bash | | Factory Droid | curl -fsSL https://memorycrystal.ai/install-droid-mcp.sh \| bash | | OpenClaw | curl -fsSL https://memorycrystal.ai/crystal \| bash | | Claude Desktop | Add the MCP server in settings (guide) | | Any MCP host | Point at https://api.memorycrystal.ai/mcp with a Bearer token |

The universal installer supports cloud, local, and self-hosted backends. It can register MCP clients, configure OpenClaw, install Codex/Claude hook assets, and stage a Dockerized local Convex backend for offline or self-hosted work.

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How it works

  You send a message
       │
       ▼
┌─────────────────────────────────────────┐
│           CONTEXT ENGINE                │
│                                         │
│  Semantic search + BM25 across STM/LTM  │
│  Knowledge graph boost                  │
│  Multi-signal reranker                  │
│  Diversity filter + context budgeting   │
│  → Inject top memories into context     │
└─────────────────────────────────────────┘
       │
       ▼
  AI responds with full context
       │
       ▼
┌─────────────────────────────────────────┐
│         MEMORY EXTRACTION               │
│                                         │
│  Raw message → Short-term memory        │
│  LLM extracts facts/decisions → LTM     │
│  Graph enrichment links related memories│
└─────────────────────────────────────────┘

Every response is informed by what came before. Every conversation feeds the next one.

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Two memory layers

| Layer | Stores | Retention | |---|---|---| | Short-term (STM) | Recent raw messages, verbatim | Rolling window by tier | | Long-term (LTM) | Facts, decisions, lessons, people, rules | Permanent, vector-indexed | | Sensory raw content | Raw sensory payloads behind memory records | Summarized, tombstoned, or protected by policy |

STM gives recent continuity. LTM gives permanent knowledge. Sensory retention lets Memory Crystal keep durable recall value without keeping every raw payload forever.

Five memory stores

| Store | Purpose | Example | |---|---|---| | sensory | Raw signals | "the user sounds frustrated about the deploy" | | episodic | Events | "We shipped v2 on March 15" | | semantic | Facts | "The API uses Convex for the backend" | | procedural | How-to | "Deploy with npm run convex:deploy" | | prospective | Plans | "Add billing webhooks next sprint" |

Knowledge graph

Memories don't exist in isolation. An async background job connects related memories — decisions link to the lessons that informed them, people link to their projects, rules link to the events that created them.

When the Context Engine searches, graph-connected memories rank higher. Your AI doesn't just remember facts — it understands relationships.

Adaptive recall

Six modes, automatically selected:

| Mode | Prioritizes | |---|---| | General | Broad recall across STM + LTM | | Decision | Decisions, lessons, and rules before risky changes | | Project | Goals, workflows, and implementation context | | People | Ownership, collaborators, and relationships | | Workflow | Procedures, rules, and how-to memory | | Conversation | Recent session context and continuity |

The Context Engine picks the right mode. You don't configure anything.

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Knowledge bases

First-class immutable reference collections for docs, policies, runbooks, and imported source material. They sit alongside conversational memory so your agent can keep learned context and stable reference data separate.

• Immutable — imported chunks stay stable, not rewritten by conversation
• Scoped — tenant and scope filters keep KBs private to the right workspace
• Bulk import — standard import or high-volume bulk-insert without blocking on embedding
• Background enrichment — embedding and graph backfill run asynchronously

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24 memory tools

Every tool works in any MCP host or automatically within OpenClaw hooks.

| Tool | What it does | |---|---| | crystal_recall | Semantic search across all long-term memory | | crystal_remember | Store a memory — decisions, facts, lessons | | crystal_what_do_i_know | Everything known about a topic | | crystal_why_did_we | Decision archaeology — why a past choice was made | | crystal_preflight | Pre-flight check before risky actions | | crystal_search_messages | Hybrid search over verbatim conversation history | | crystal_checkpoint | Snapshot memory state at a milestone | | crystal_wake | Session startup — briefing and guardrails | | crystal_trace | Trace a memory back to its source conversation | | crystal_who_owns | Find ownership of a file, module, or area | | crystal_explain_connection | Explain relationships between concepts | | crystal_dependency_chain | Trace dependency chains between entities | | crystal_recent | Recent messages for short-term context | | crystal_edit | Update an existing memory | | crystal_forget | Archive or delete a memory | | crystal_stats | Memory and usage statistics | | crystal_set_scope | Override channel scope for the session | | crystal_list_knowledge_bases | List available knowledge bases | | crystal_query_knowledge_base | Search a knowledge base | | crystal_import_knowledge | Import reference chunks into a KB | | crystal_ideas | List active Organic ideas and discoveries | | crystal_idea_action | Act on Organic ideas | | memory_search | Search LTM and return crystal paths | | memory_get | Read a full memory by ID or path |

Short-term message tools (crystal_search_messages, crystal_recent, recall message matches, and wake/session summaries derived from recent messages) redact likely secrets before returning tool output. A turn becomes searchable after capture finishes at turn completion; active same-turn tool calls should not expect the current prompt or response to appear yet.

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HTTP API

All core operations available over authenticated HTTP:

POST /api/mcp/capture              Create a memory
POST /api/mcp/recall               Hybrid recall over all memory
POST /api/mcp/search-messages      Search short-term history

GET  /api/knowledge-bases          List knowledge bases
POST /api/knowledge-bases          Create a knowledge base
POST /api/knowledge-bases/:id/import       Import chunks
POST /api/knowledge-bases/:id/bulk-insert  High-volume migration
POST /api/knowledge-bases/:id/query        Query a knowledge base

All endpoints require Authorization: Bearer . Per-key rate limiting enforced.

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Architecture

memorycrystal/
├── plugin/                 OpenClaw plugin — hooks into conversation lifecycle
├── plugins/shared/         Shared hook script for Claude Code, Codex, Factory
├── mcp-server/             MCP server — stdio/HTTP compatibility layer
├── packages/mcp-server/    Streamable HTTP MCP variant
├── convex/                 Backend — schema, capture, recall, graph, retention
│   └── crystal/            All Memory Crystal Convex functions
├── apps/
│   ├── web/                Next.js 15 dashboard (Tailwind 4, Convex Auth)
│   └── docs/               Mintlify documentation site
├── scripts/                Install, bootstrap, doctor, enable/disable
└── assets/                 Logos and brand assets

Local development

Contributors can run an opt-in Dockerized Convex backend and dashboard locally, then seed fixture data without touching the managed production deployment:

npm run convex:local:up
npm run convex:local:seed
npm run convex:local:doctor

Provider keys are intentionally split: MEMORY_CRYSTAL_API_KEY is client bearer auth, GEMINI_API_KEY powers Gemini embeddings, and optional OPENROUTER_API_KEY powers organic model features.

The local stack uses http://127.0.0.1:3210 for Convex RPC, http://127.0.0.1:3211 for HTTP actions, and http://127.0.0.1:6791 for the dashboard. See the Local-First Setup guide for end-user setup, local endpoints, backup and rollback behavior, and troubleshooting.

Self-hosted

Run everything on your own infrastructure:

git clone https://github.com/memorycrystal/memorycrystal.git
cd memorycrystal && npm install

# Deploy to your own Convex project
CONVEX_DEPLOYMENT=prod:your-project-123 npx convex deploy

# Configure
echo 'CONVEX_URL=https://your-project-123.convex.cloud' > mcp-server/.env
echo 'GEMINI_API_KEY=your-key' >> mcp-server/.env

# Enable and verify
npm run crystal:enable
npm run crystal:doctor

For install-script OpenClaw installs, verify the loaded plugin directly:

openclaw plugins info crystal-memory
openclaw crystal_status

Full guide: docs.memorycrystal.ai/configuration/self-hosting

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Security

• Multi-tenant isolation — owner checks on every retrieval, database-level separation
• API keys — SHA-256 hashed at rest, plaintext never stored
• Content scanner — blocks prompt injection, encoded payloads, credential patterns
• Prompt injection mitigation — recalled memories injected as informational context only
• Rate limiting — per-key enforcement on all endpoints
• Audit logging — all actions logged to crystalAuditLog
• Device flow auth — RFC 8628-style for CLI key provisioning
• Local mode — SQLite fallback, data never leaves your machine

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Pricing

| Plan | Price | Memories | STM Retention | |---|---|---|---| | Free | $0/mo | 500 | 7 days | | Pro | $29/mo | 25,000 | 30 days | | Ultra | $79/mo | Unlimited | 90 days | | Enterprise | Custom | Custom | Custom |

Self-hosting is always free. Paid plans are for the managed cloud at memorycrystal.ai.

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Contributing

Memory Crystal is MIT open source. PRs welcome.

git clone https://github.com/memorycrystal/memorycrystal.git
cd memorycrystal && npm install && npm run dev

Star History

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MIT License — memorycrystal.ai — Operated by Illumin8 Inc.

Source & license

This open-source MCP server is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: memorycrystal
• Source: memorycrystal/memorycrystal
• License: MIT

Install and usage instructions live in the source repository linked above.