Elen MCP server

Elen Learning Nodes for Agents

Elen is an open-source MCP server that records the decisions your coding agent makes, with the limits that bound them, and marks old decisions as superseded. It installs with one npx line, works with Cursor, Claude Code and any MCP client, and keeps decisions in a local SQLite file.

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The Problem

Agents burn massive amounts of context window tokens re-litigating the same architectural decisions, searching for the same constraints, and writing the same rationale. Chat logs are ephemeral. Standard vector DBs flood the context window with fuzzy, irrelevant text.

What Elen Does

Elen gives agents a Token-Efficient Decision Memory Protocol. It allows agents to build a permanent, immutable graph of decisions (the "Elen Decision Network") without destroying their context limits.

Instead of stuffing the prompt with past chats, Elen forces a pointer-first retrieval model:

1. SUGGEST — Retrieve only minimal Top-K pointer IDs (dec:ENG-1a2b).
2. EXPAND — Only fetch the full text if the pointer is explicitly requested.
3. COMMIT — Write decisions using hashed constraint sets to avoid duplication.
4. SUPERSEDE — Explicitly deprecate outdated decisions to advance the graph.

"Agents don't get smarter with bigger models. They get smarter with better reasoning processes. Elen is that process."

Quick Start

import { Elen } from '@learningnodes/elen';

const elen = new Elen({
  agentId: 'frontend-agent',
  projectId: 'my-project', // auto-detected from git remote if omitted
  storage: 'sqlite',
});

// 1. Suggest (Pointer-First Retrieval)
const pointers = await elen.suggest('checkout latency constraints');
// Returns: [{ id: 'dec:MKT-9f21', summary: 'Mobile checkout rendering SLAs' }]

// 2. Expand (On-Demand Materialization)
const record = await elen.expand('dec:MKT-9f21');
// Resolves full constraints: "All checkout flows must render under 1.5s"

// 3. Commit (Graph Wiring)
const newDecision = await elen.commit({
  question: 'Which payment element to use?',
  domain: 'frontend',
  decisionText: 'Stripe Elements (native rendering over redirect)',
  constraints: ['must render < 1.5s', 'PCI compliant'],
  refs: ['dec:MKT-9f21'] // Explicitly linking to Marketing's constraint
});

console.log(newDecision.decision_id); // dec:FRN-a1b2c3 - Frozen, queryable

Via MCP (zero-code integration)

Add Elen as an MCP server — your agent gets tools with descriptions that tell it when to use them. No SDK required.

{
  "mcpServers": {
    "elen": {
      "command": "npx",
      "args": ["-y", "@learningnodes/elen-mcp@0.3.1"]
    }
  }
}

Project identity (DS-0.5)

projectid is resolved in this order — never** from your OS username:

1. --project flag or "project" in ~/.elen/config.json
2. Optional venture_map in config (folder segment → project, e.g. learningnodes across many repos)
3. Normalized git remote get-url origin → owner/repo
4. Git repo root directory name

If resolution fails, MCP/CLI exits with guidance instead of writing to a wrong namespace.

{
  "project": "my-app",
  "venture_map": {
    "learningnodes": ["marketplace-repos", "elen"]
  }
}

Observability & CLI

Shortened. The full README is on GitHub.