Synapse - Universal AI Memory over MCP

A local-first memory layer that gives any AI client persistent, semantic, cross-tool recall, exposed over the Model Context Protocol.

Built for Hackverse X - Global Tech Innovation 2026. Track: LLM with MCP.

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The problem

Every large language model is brilliant but amnesiac. Each conversation starts from zero, context is trapped inside a single tool, and users repeat their preferences, stack, and decisions over and over. The intelligence is there; the continuity is not.

The solution

Synapse is a memory server speaking the Model Context Protocol. Any MCP-compatible client (Cursor, Claude Desktop, or your own agent) can call Synapse to remember durable facts and recall them semantically in any future session, across any tool.

• Open protocol - memory is portable across every MCP client, not locked to one vendor.
• Local-first and private - runs on your machine with an embedded vector database; memories never have to leave your device.
• Zero-key by default - on-device embeddings (all-MiniLM-L6-v2) mean semantic recall works with no API key, no signup, and no cloud cost.

What is in the box

Piece	What it does
MCP server	Six tools (remember, recall, list_memories, forget, get_related, build_context), a memory://recent resource, and a recall-context prompt - over stdio and Streamable HTTP.
Memory core	sqlite-vec vector store + pluggable embeddings (on-device Transformers.js, optional OpenAI).
Web app	A beautiful, animated Next.js site: marketing landing, a memory dashboard (timeline, semantic search, live knowledge graph), and an agent playground that proves cross-session recall in the browser.

Architecture

MCP clients (Cursor, Claude, in-app agent)
        |  stdio / Streamable HTTP
        v
  MCP server  ──────────────► shared tool specs (lib/mcp/tools.ts)
        |                              |
        v                              v
  embeddings (local / OpenAI)   memory store (sqlite-vec)

The same tool definitions power the stdio server, the HTTP route, and the in-app agent, so behaviour is identical everywhere.

Quick start

Requirements: Node.js 20+ (developed on Node 23).

npm install
npm run dev

Open http://localhost:3000.

• / - landing page
• /dashboard - browse, search, add, and visualize memories
• /playground - chat with an agent that remembers (no key needed)
• /connect - copy-paste config to connect Cursor / Claude Desktop

On first use Synapse downloads a ~90MB on-device embedding model and caches it. After that, semantic memory runs fully offline.

Connect a real MCP client

Cursor / Claude Desktop (stdio)

Add to your client's MCP config (for Cursor, .cursor/mcp.json). Replace the path with this repo's absolute path:

{
  "mcpServers": {
    "synapse": {
      "command": "npx",
      "args": ["-y", "tsx", "/absolute/path/to/Hackathon/mcp/stdio.ts"]
    }
  }
}

The exact snippet (with the correct absolute path filled in) is shown on the /connect page.

HTTP (Streamable HTTP, JSON mode)

Start the app and point an HTTP-capable MCP client at http://localhost:3000/api/mcp. Quick smoke test:

curl -s -X POST http://localhost:3000/api/mcp \
  -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}'

Optional configuration

Copy .env.example to .env.local. Everything works with no env vars set.

Variable	Purpose
SYNAPSE_EMBEDDINGS	local (default) or openai.
OPENAI_API_KEY	Enables a live LLM agent in the Playground and optional cloud embeddings.
OPENAI_BASE_URL / OPENAI_CHAT_MODEL / OPENAI_EMBED_MODEL	OpenAI-compatible endpoint settings.
SYNAPSE_DB_PATH	Where the SQLite memory database lives (default ./data/synapse.db).

MCP tools

Tool	Description
remember	Store a memory durably (content, optional tags, source).
recall	Semantic search over memories (query, optional limit).
list_memories	List the most recent memories.
forget	Delete a memory by id.
get_related	Find memories semantically related to an id (powers the graph).
build_context	Synthesize a ready-to-inject context block for a query.

Tech stack

Next.js (App Router) · React · TypeScript · Tailwind CSS · Framer Motion · @modelcontextprotocol/sdk · better-sqlite3 + sqlite-vec · @huggingface/transformers.

Scripts

Command	Description
npm run dev	Start the web app.
npm run build / npm start	Production build and serve.
npm run mcp:stdio	Run the MCP server over stdio.
npm run smoke	Verify the memory core (sqlite-vec + embeddings).

Project layout

app/            Next.js routes (pages + API)
components/      UI components (nav, hero, graph, icons)
lib/memory/      vector store + embeddings
lib/mcp/         MCP server + shared tool specs
lib/agent/       in-app agent (live + demo mode)
mcp/stdio.ts     stdio entry point for local MCP clients
docs/            pitch, demo script, devpost copy

License

MIT.