moltmind
Agent Memory MCP Server β persistent semantic memory and session continuity for AI agents
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MoltMind
Persistent semantic memory and session continuity for AI agents. One install, zero config, runs 100% locally.
MoltMind is an MCP server that gives your AI agent long-term memory across sessions β storing learnings, decisions, error fixes, and handoff context using local SQLite and embeddings. No API keys, no cloud, no accounts needed.
Why MoltMind?
Every time your AI agent starts a new conversation, it forgets everything. It spends 1-2 minutes re-reading your files, re-learning your architecture, and re-discovering decisions you already made. MoltMind gives it memory β your agent picks up right where it left off in seconds.
| Without MoltMind | With MoltMind | |
|---|---|---|
| Model used | Claude Opus 4.6 ($5/$25 per 1M tokens) | |
| Time per session | 1-2 min re-exploring | Seconds to resume |
| Cost per session | ~$0.09 | ~$0.009 |
| 20 sessions | $1.80 | $0.18 |
| Daily use (1 year) | $32.85 | $3.29 |
| Time saved (1 year) | β | ~6 hours |
| Money saved (1 year) | β | ~$30 |
Assumes ~8,000 input + ~2,000 output tokens per cold start, ~825 input + ~200 output per resume. Savings scale with usage β power users save more.
Quick Start
Claude Code
claude mcp add moltmind -- npx -y moltmind
Restart Claude Code, then run /mcp to verify.
With moltbook social features:
claude mcp add moltmind -- npx -y moltmind --moltbook
See moltbook.com for the agent social network.
Other Clients
Add to your client's MCP config file:
{
"mcpServers": {
"moltmind": {
"command": "npx",
"args": ["-y", "moltmind"]
}
}
}
With moltbook: "args": ["-y", "moltmind", "--moltbook"]
| Client | Config file | Key |
|---|---|---|
| Cursor | ~/.cursor/mcp.json or .cursor/mcp.json | mcpServers |
| Windsurf | ~/.codeium/windsurf/mcp_config.json | mcpServers |
| VS Code (Copilot) | .vscode/mcp.json | servers |
| Cline | Settings > MCP Servers > Edit Config | mcpServers |
| Codex CLI | ~/.codex/config.json | mcpServers |
| Any MCP client | Varies | mcpServers |
Note: VS Code uses
"servers"instead of"mcpServers"as the top-level key.
Upgrading
npx -y moltmind always fetches the latest version. If you have a stale global install:
npm uninstall -g moltmind # then let npx handle it
Tools
14 core tools by default, 21 with --moltbook:
| Tool | Description |
|---|---|
mm_store | Store a memory (learning, error fix, decision, plan, or raw note) |
mm_recall | Search memories β hybrid semantic + keyword search |
mm_read | Read a specific memory by ID |
mm_update | Update an existing memory |
mm_delete | Archive a memory (soft delete) |
mm_status | Server health dashboard |
mm_init | Create a project-local memory vault |
mm_handoff_create | Structured handoff for agent-to-agent context transfer |
mm_handoff_load | Load the most recent handoff |
mm_session_save | Save session summary and where you left off |
mm_session_resume | Restore context from recent sessions |
mm_session_history | Browse past sessions with tool call stats |
mm_feedback | Report bugs or request features |
mm_metrics | Adoption and health metrics dashboard |
How It Works
Memory & Search β Your agent stores memories in a local database. When it needs to find something, MoltMind searches by meaning (not just keywords) β so searching for "API port" finds a memory about "our server runs on port 8080". If the search model isn't downloaded yet, it falls back to keyword matching.
Sessions & Handoffs β Sessions are auto-created on startup and auto-paused on shutdown. Your agent saves where it left off and picks up seamlessly next time. Handoffs let one agent pass context to another with structured goal/state/next-action documents.
Diagnostics β Every tool call is logged locally with timing and success/failure. mm_status shows health, mm_metrics shows usage stats and token savings. All data stays on your machine.
What It Costs (Tokens)
Every MCP tool adds a small overhead to each request because the AI needs to know what tools are available. Here's what MoltMind costs β and what it saves you:
| Cost per request | In dollars | |
|---|---|---|
| MoltMind overhead (14 tools) | ~500 tokens | ~$0.0015 |
| With prompt caching | ~50 tokens | ~$0.00015 |
| Session resume (saves you) | ~7,675 tokens | ~$0.023 |
Bottom line: MoltMind pays for itself after a single session resume. Every conversation after that is pure savings.
Free vs Pro
| Free | Pro ($9 one-time) | |
|---|---|---|
| Stores per day | 20 | Unlimited |
| Total memories | 200 | Unlimited |
| Search | Unlimited | Unlimited |
| Session tools | Unlimited | Unlimited |
| Vector search | Brute-force | Zvec ANN (auto) |
Upgrade to Pro
From your terminal
macOS / Linux:
npx moltmind --upgrade
Windows (Command Prompt or PowerShell):
npx moltmind --upgrade
Same command on all platforms. A checkout page opens in your browser, you pay $9, and the terminal waits up to 5 minutes for payment. Once confirmed, your license activates automatically β no copy-pasting keys, no config files.
Prerequisite: You must have run MoltMind at least once before upgrading (so your machine ID exists at
~/.moltmind/instance_id). If you just installed, open your AI client, let MoltMind start, then come back and run--upgrade.
From inside your AI agent
If you're already in a conversation with an agent that has MoltMind installed, just say:
"Upgrade MoltMind to Pro"
Your agent will run npx moltmind --upgrade for you, the checkout page opens, and the license activates after payment. Works in Claude Code, Cursor, Windsurf, Cline, Codex CLI β any client where MoltMind is installed.
After payment
- License is written to
~/.moltmind/license.key - Zvec ANN search auto-enables on next startup
mm_statusshows "Pro" tier- Restart your MCP client to pick up the change
Machine lock and migration
Pro licenses are tied to one machine (your instance_id). A daily heartbeat check enforces this.
- Switching machines? Run
npx moltmind --upgradeon the new one. Your old machine reverts to free within 24 hours. - Offline? A 7-day grace period keeps Pro active while you're disconnected.
- All data stays local. The heartbeat only sends your machine ID and license prefix β no memory content ever leaves your machine.
Search Performance (Pro)
Pro tier uses Zvec ANN for fast memory search. Here's what that means in practice:
Accuracy β At 1,000 memories (a typical heavy user), Zvec finds 98% of the exact same results as an exhaustive search. Your agent gets the right answer almost every time.
Speed β Search takes under 1ms at 1,000 memories. At 10,000 memories, it's still under 5ms. Your agent won't notice any delay.
Reliability β Handles 330+ searches per second with zero latency spikes. Deleted memories never come back. Results are deterministic.
See BENCHMARK_RESULTS.md for the full report, or RUNBOOK.md for how to run benchmarks yourself.
Data Storage
| Path | Purpose |
|---|---|
~/.moltmind/memory.db | Global memory vault |
./.moltmind/memory.db | Project-local vault (via mm_init) |
~/.moltmind/models/ | Cached embedding model (~22MB) |
~/.moltmind/instance_id | Anonymous instance identifier |
~/.moltmind/license.key | Pro license (after upgrade) |
Requirements
- Node.js 18+
- No API keys required
- No internet after first embedding model download
License
MIT
