Chat Clients

Use Foldr with GPT4All (MCP)

GPT4All is Nomic's privacy-first desktop app for running local models with a built-in Local Docs RAG system. Recent versions expose an experimental MCP bridge for external tools. Foldr lets GPT4All go from a private read-only assistant to one that can actually publish output to the web on demand.

NomicmacOS, Windows, LinuxMCP: experimental

Installation

Add the Foldr MCP server to GPT4All with the snippet below. Replace fs_… with an API key from foldr.space/developers/signup. Each upload costs 5¢ - top up account credits or subscribe to Pro tier to bypass per-call charges.

{
  "mcpServers": {
    "foldr": {
      "command": "npx",
      "args": ["-y", "@foldr/mcp-server"],
      "env": { "FOLDR_API_KEY": "fs_live_..." }
    }
  }
}

Setup tip: GPT4All → Settings → Application → Integrations → MCP Servers.

Official GPT4All MCP docs

What You Can Do

Upload any file from GPT4All to Foldr and get a permanent shareable URL back in the same turn (5¢ per upload, debited from credits)
Mint short-lived capability tokens to share files with downstream agents without leaking your API key
Organize uploads into per-API-key folders with hierarchical structure
Shorten long URLs to foldr.space/s/... links - free with any API key
Let chat participants retrieve uploaded files by asking for them by filename

GPT4All + Foldr FAQ

How do I install the Foldr MCP server in GPT4All?

Open GPT4All's MCP configuration (the JSON settings file) and paste the config block shown above. Set FOLDR_API_KEY to a key you create at foldr.space/developers/signup. Restart GPT4All if it doesn't hot-reload.

How much does it cost to use Foldr from GPT4All?

Each upload costs 5¢. You can pay by topping up account credits via the `top_up_credits` MCP tool (min $5) - every upload then debits from balance. Or subscribe to Pro tier ($25/mo) and per-call charges are bypassed entirely. Tools that don't write data (list_files, mint_capability, get_usage, etc.) are free.

I set the key but GPT4All says the Foldr tool isn't available - what's wrong?

Three common causes: (1) GPT4All wasn't restarted after editing the config - most MCP hosts need a restart to pick up new servers. (2) The API key is wrong or missing - verify the env var name your client reads (e.g. FOLDR_API_KEY) matches the config snippet above. (3) Your client doesn't support the streamable-http transport - most modern clients do, but check GPT4All's docs for the version that added MCP support.

Can GPT4All upload files directly to Foldr, or just generate URLs?

GPT4All can do both. The MCP server exposes tools for `upload_file` (base64-encoded file content), `bulk_upload` (up to 20 files in one call), `mint_capability` (short-lived shareable links), and `create_short_url`. Any file GPT4All can read from disk can be uploaded.

Is the Foldr MCP integration with GPT4All production-ready?

Foldr's MCP server is stable and used in production - streamable-http transport at https://foldr.space/api/mcp with 23 tools. GPT4All's MCP support is currently experimental - expect rough edges and breaking changes. Every write endpoint accepts an Idempotency-Key so retries are safe.

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Connect GPT4All to Foldr in under a minute

Grab an API key, paste the snippet above into GPT4All's MCP config, top up credits (or grab a Pro subscription), and your agent can upload files and mint share links immediately.

Get your Foldr API key x402 details