NEXO Brain — Your AI Gets a Brain

NEXO Brain transforms any MCP-compatible AI agent from a stateless assistant into a cognitive partner that remembers, learns, forgets, adapts, and builds a relationship with you over time.

Watch the overview on YouTube

Every time you close a session, everything is lost. Your agent doesn't remember yesterday's decisions, repeats the same mistakes, and starts from zero. NEXO Brain fixes this with a cognitive architecture modeled after how human memory actually works.

The Problem

AI coding agents are powerful but amnesic:

• No memory — closes a session, forgets everything
• Repeats mistakes — makes the same error you corrected yesterday
• No context — can't connect today's work with last week's decisions
• Reactive — waits for instructions instead of anticipating needs
• No learning — doesn't improve from experience
• No safety — stores anything it's told, including poisoned or redundant data

The Solution: A Cognitive Architecture

NEXO Brain implements the Atkinson-Shiffrin memory model from cognitive psychology (1968) — the same model that explains how human memory works:

What you say and do
    |
    +---> Sensory Register (raw capture, 48h)
    |       |
    |       +---> Attention filter: "Is this worth remembering?"
    |               |
    |               v
    +---> Short-Term Memory (7-day half-life)
    |       |
    |       +---> Used often? --> Consolidate to Long-Term Memory
    |       +---> Not accessed? --> Gradually forgotten
    |
    +---> Long-Term Memory (60-day half-life)
            |
            +---> Active: instantly searchable by meaning
            +---> Dormant: faded but recoverable ("oh right, I remember now!")
            +---> Near-duplicates auto-merged to prevent clutter

This isn't a metaphor. NEXO Brain literally implements Ebbinghaus forgetting curves, rehearsal-based reinforcement, and memory consolidation during automated "sleep" processes.

What Makes NEXO Brain Different

How the Brain Works

Memory That Forgets (And That's a Feature)

NEXO Brain uses Ebbinghaus forgetting curves — memories naturally fade over time unless reinforced by use. This isn't a bug, it's how useful memory works:

• A lesson learned yesterday is strong. If you never encounter it again, it fades — because it probably wasn't important.
• A lesson accessed 5 times in 2 weeks gets promoted to long-term memory — because repeated use proves it matters.
• A dormant memory can be reactivated if something similar comes up — the "oh wait, I remember this" moment.

Semantic Search (Finding by Meaning)

NEXO Brain doesn't search by keywords. It searches by meaning using vector embeddings (fastembed, 384 dimensions).

Example: If you search for "deploy problems", NEXO Brain will find a memory about "SSH connection timeout on production server" — even though they share zero words. This is how human associative memory works.

Metacognition (Thinking About Thinking)

Before every code change, NEXO Brain asks itself: "Have I made a mistake like this before?"

It searches its memory for related errors, warnings, and lessons learned. If it finds something relevant, it surfaces the warning BEFORE acting — not after you've already broken production.

Cognitive Dissonance

When you give an instruction that contradicts established knowledge, NEXO Brain doesn't silently obey or silently resist. It verbalizes the conflict:

"My memory says you prefer Tailwind over plain CSS, but you're asking me to write inline styles. Is this a permanent change or a one-time exception?"

You decide: paradigm shift (permanent change), exception (one-time), or override (old memory was wrong).

Sibling Memories

Some memories look identical but apply to different contexts. "How to deploy" for Project A is different from Project B. NEXO Brain detects discriminating entities (different OS, platform, language) and links them as siblings instead of merging them:

"Applying the Linux deploy procedure. Note: there's a sibling for macOS that uses a different port."

Trust Score (0-100)

NEXO Brain tracks alignment with you through a trust score:

• You say thanks --> score goes up --> reduces redundant verification checks
• Makes a mistake you already taught it --> score drops --> becomes more careful, checks more thoroughly
• The score doesn't control permissions — you're always in control. It's a mirror that helps calibrate rigor.

Sentiment Detection

NEXO Brain reads your tone (keywords, message length, urgency signals) and adapts:

• Frustrated? --> Ultra-concise mode. Zero explanations. Just solve the problem.
• In flow? --> Good moment to suggest that backlog item from last Tuesday.
• Urgent? --> Immediate action, no preamble.

Sleep Cycle

Like a human brain, NEXO Brain has automated processes that run while you're not using it:

If your Mac was asleep during any scheduled process, NEXO Brain catches up in order when it wakes.

Cognitive Features (v0.3.1)

NEXO Brain v0.3.1 adds 21 cognitive tools on top of the 76 base tools, bringing the total to 97+ MCP tools. These features implement cognitive science concepts that go beyond basic memory:

Input Pipeline

Memory Management

Retrieval

Proactive

Quick Start

Claude Code (Primary)

npx nexo-brain

The installer handles everything:

  How should I call myself? (default: NEXO) > Atlas

  Can I explore your workspace to learn about your projects? (y/n) > y

  Keep Mac awake so my cognitive processes run on schedule? (y/n) > y

  Installing cognitive engine dependencies...
  Setting up NEXO home...
  Scanning workspace...
    - 3 git repositories
    - Node.js project detected
  Configuring MCP server...
  Setting up automated processes...
    5 automated processes configured.
  Caffeinate enabled.
  Generating operator instructions...

  +----------------------------------------------------------+
  |  Atlas is ready. Type 'atlas' to start.                  |
  +----------------------------------------------------------+

Starting a Session

The installer creates a shell alias with your chosen name. Just type it:

atlas

That's it. No need to run claude manually. Atlas will greet you immediately — adapted to the time of day, resuming from where you left off if there's a previous session. No cold starts, no waiting for your input.

What Gets Installed

Requirements

• macOS (Linux support planned)
• Node.js 18+ (for the installer)
• Claude Opus (latest version) strongly recommended. NEXO Brain provides 97+ MCP tools across 17 categories. This cognitive load requires a top-tier model with large context window. Smaller models (Haiku, Sonnet) may struggle with tool selection and produce inconsistent results. Opus handles all 97+ tools without hesitation.
• Python 3, Homebrew, and Claude Code are installed automatically if missing.

Architecture

97+ MCP Tools across 17 Categories

Plugin System

NEXO Brain supports hot-loadable plugins. Drop a .py file in ~/.nexo/plugins/:

# my_plugin.py
def handle_my_tool(query: str) -> str:
    """My custom tool description."""
    return f"Result for {query}"

TOOLS = [
    (handle_my_tool, "nexo_my_tool", "Short description"),
]

Reload without restarting: nexo_plugin_load("my_plugin.py")

Data Privacy

• Everything stays local. All data in ~/.nexo/, never uploaded anywhere.
• No telemetry. No analytics. No phone-home.
• No cloud dependencies. Vector search runs on CPU (fastembed), not an API.
• Auto-update is opt-in. Checks GitHub releases, never sends data.
• Secret redaction. API keys and tokens are stripped before they ever reach memory storage.

The Psychology Behind NEXO Brain

NEXO Brain isn't just engineering — it's applied cognitive psychology:

Integrations

Claude Code (Primary)

NEXO Brain is designed as an MCP server. Claude Code is the primary supported client:

npx nexo-brain

All 97+ tools are available immediately after installation. The installer configures Claude Code's ~/.claude/settings.json automatically.

OpenClaw

NEXO Brain also works as a cognitive memory backend for OpenClaw:

MCP Bridge (Zero Code)

Add NEXO Brain to your OpenClaw config at ~/.openclaw/openclaw.json:

{
  "mcp": {
    "servers": {
      "nexo-brain": {
        "command": "python3",
        "args": ["~/.nexo/src/server.py"],
        "env": {
          "NEXO_HOME": "~/.nexo"
        }
      }
    }
  }
}

Or via CLI:

openclaw mcp set nexo-brain '{"command":"python3","args":["~/.nexo/src/server.py"],"env":{"NEXO_HOME":"~/.nexo"}}'
openclaw gateway restart

ClawHub Skill

npx clawhub@latest install nexo-brain

Native Memory Plugin

npm install @wazionapps/openclaw-memory-nexo-brain

{
  "plugins": {
    "slots": {
      "memory": "memory-nexo-brain"
    }
  }
}

This replaces OpenClaw's default memory system with NEXO Brain's full cognitive architecture.

Any MCP Client

NEXO Brain works with any application that supports the MCP protocol. Configure it as an MCP server pointing to ~/.nexo/src/server.py.

Listed On

Inspired By

NEXO Brain builds on ideas from several open-source projects. We're grateful for the research and implementations that inspired specific features:

Contributing

See CONTRIBUTING.md for guidelines. Issues and PRs welcome.

License

MIT -- see LICENSE

Built by WAzion