# The PrintPal MCP server: 3D printing tools for any AI agent

> One free remote MCP endpoint with 16 tools for 3D printing. Works in any client that speaks Streamable HTTP.

Page: https://printpal.io/integrations/mcp-server
Updated: 2026-10-27

The **PrintPal MCP server** is a free, public Model Context Protocol server at `https://printpal.io/mcp`, published by [PrintPal](https://printpal.io/) as `io.printpal/printpal` in the official MCP Registry. It gives AI assistants and agents 16 tools for 3D printing: searching a community library of printable models, print-cost and calibration calculators, a vendor-neutral troubleshooting wiki with full-text fetch for citations, Arduino and ESP32 build guides, and hand-offs to PrintPal's AI 3D generator and parametric AI CAD agent.

It speaks stateless Streamable HTTP with plain JSON responses, needs no authentication, and also exposes every tool as a REST endpoint with an OpenAPI 3.1 description. An optional PrintPal API key unlocks credit-metered AI 3D generation.

## At a glance

- **Endpoint:** `https://printpal.io/mcp`
- **Transport:** Streamable HTTP, stateless, JSON responses (no SSE)
- **Authentication:** None. Optional `Authorization: Bearer <API key>` for AI generation.
- **Tools / prompts / resources:** 16 / 3 / 2
- **Registry name:** `io.printpal/printpal`
- **Server card:** [/.well-known/mcp.json](https://printpal.io/.well-known/mcp.json)
- **REST + OpenAPI:** `POST /mcp/rest/<tool>` · [/mcp/openapi.json](https://printpal.io/mcp/openapi.json)
- **Price:** Free

## Where to get it

- Official MCP Registry: io.printpal/printpal: https://registry.modelcontextprotocol.io/v0/servers?search=io.printpal/printpal
- Server card: https://printpal.io/.well-known/mcp.json
- OpenAPI 3.1: https://printpal.io/mcp/openapi.json

## Features

- **Works in every MCP client:** ChatGPT, Claude, Gemini, Cursor, VS Code with GitHub Copilot, Windsurf and any client that supports remote Streamable HTTP servers.
- **No auth, no sessions:** Stateless JSON-RPC over HTTP with CORS enabled. Nothing to sign in to and nothing to clean up.
- **Built for citations:** `search` and `fetch` follow the connector contract, so assistants can read a full wiki article and link to it.
- **MCP App widget:** Model search results come with an HTML widget (`ui://widget/printpal-models-v1.html`) that renders interactive model cards in hosts that support MCP Apps.
- **Honest annotations:** Every tool declares `readOnlyHint`, `destructiveHint` and `openWorldHint`. Only `generate_3d_model` has a side effect, and only with your key.
- **REST and OpenAPI too:** Call any tool with a JSON body at `/mcp/rest/<tool>` from scripts, Zapier or Custom GPT Actions.

## How to connect the PrintPal MCP server

1. Copy the server URL: `https://printpal.io/mcp`.
2. Add it to your client as a remote (HTTP) MCP server. Pick your client below for the exact command or config.
3. Leave authentication off. Add `Authorization: Bearer pp_live_…` only if you want AI 3D generation on your own credits.
4. Ask your assistant a 3D printing question. It will discover the 16 tools automatically.

Clients that only support local stdio servers can bridge with `npx -y mcp-remote https://printpal.io/mcp`.

### Server URL

Remote MCP, Streamable HTTP.

```text
https://printpal.io/mcp
```

### Claude Code

```bash
claude mcp add --transport http printpal https://printpal.io/mcp
```

### Gemini CLI

```bash
gemini mcp add --transport http printpal https://printpal.io/mcp
```

### Cursor (~/.cursor/mcp.json)

```json
{
  "mcpServers": {
    "printpal": { "url": "https://printpal.io/mcp" }
  }
}
```

### VS Code / GitHub Copilot (.vscode/mcp.json)

```json
{
  "servers": {
    "printpal": { "type": "http", "url": "https://printpal.io/mcp" }
  }
}
```

### Windsurf (mcp_config.json)

```json
{
  "mcpServers": {
    "printpal": { "serverUrl": "https://printpal.io/mcp" }
  }
}
```

### stdio-only clients

Bridges a local stdio client to the remote server. Requires Node.js 18+.

```json
{
  "mcpServers": {
    "printpal": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "https://printpal.io/mcp"]
    }
  }
}
```

### REST (no MCP client needed)

Every tool is also a plain JSON endpoint.

```bash
curl -s https://printpal.io/mcp/rest/calculate_print_cost \
  -H 'Content-Type: application/json' \
  -d '{"print_weight_grams": 45, "print_time_hours": 3.5}'
```

## Prompts to try

- Find me a 3D printable headphone stand.
- How much will a 45 g, 3.5 hour PLA print cost me?
- What are the magic layer heights for an Ender 3 with a 0.4 mm nozzle?
- My ABS print is warping at the corners. What should I change? Cite your sources.
- Show me an Arduino + 3D printed desk gadget I can build this weekend.
- Design a wall bracket for a 60 x 40 mm power supply with M3 holes 50 mm apart.

## The 16 PrintPal tools

Every AI assistant integration exposes the same tools from the PrintPal MCP server. Fifteen are read-only; only `generate_3d_model` can spend credits, and only when you add your own API key.

| Tool | What it does | API key? |
|---|---|---|
| `search_3d_models` | Find printable STL, 3MF and OBJ models in the PrintPal community library, with thumbnail, author, license and stats. | No |
| `get_3d_model` | Details, files, license and the download link for one model. | No |
| `calculate_print_cost` | Material, electricity, machine wear, labor and failure allowance, plus a suggested selling price. | No |
| `calculate_filament_usage` | Filament grams to metres to cost, and how much is left on a spool. | No |
| `calculate_layer_heights` | Z-axis "magic number" layer heights for your printer's leadscrew and stepper. | No |
| `calculate_volumetric_flow` | Check a print speed and layer height against your hotend's volumetric flow limit. | No |
| `search_learning_resources` | Search the vendor-neutral 3D printing wiki, OpenSCAD and AI CAD docs, video tutorials and Academy courses. | No |
| `search_build_guides` | Find Arduino / ESP32 + 3D-printed project guides by idea, difficulty, time and cost. | No |
| `get_build_guide` | Bill of materials, downloadable files and every step of one build guide. | No |
| `design_parametric_cad` | Turn a part description into a precise CAD brief and a link that opens PrintPal's AI CAD agent prefilled. | No |
| `generate_3d_model` | AI text-to-3D and image-to-3D. Without a key it returns a prefilled link to printpal.io; with your API key it starts the generation on your credits. | Optional |
| `check_3d_generation` | Poll a generation started with your key and get the download link. | Yes |
| `find_3d_printing_tool` | Recommend the right free PrintPal browser tool or calculator for a task. | No |
| `get_pricing_and_plans` | What is free, how credits work and which plan fits. | No |
| `search` | Search everything on PrintPal at once: models, tools, wiki, docs, videos, guides and courses. | No |
| `fetch` | Read any search result in full (for example a wiki article) so the assistant can quote and cite it. | No |

## Built-in prompts

Clients that support MCP prompts (Claude, Cursor and others) list these as one-click starting points.

| Prompt | Arguments | What it does |
|---|---|---|
| `troubleshoot_print` | problem, printer, material | Diagnoses a failed print and cites the PrintPal wiki articles it used. |
| `design_a_part` | what, dimensions | Checks the library for an existing model, otherwise drafts a CAD brief and opens the AI CAD agent. |
| `plan_a_build` | idea, skill_level | Finds a matching build guide with its bill of materials and steps. |

## Endpoints

Everything the server exposes over HTTP.

| Path | Purpose |
|---|---|
| `POST /mcp` | JSON-RPC over Streamable HTTP (stateless). Batches supported. |
| `GET /.well-known/mcp.json` | Server card: transport, auth, tools and links, for crawlers and registries. |
| `GET /mcp/openapi.json` | OpenAPI 3.1 description of the REST shim, for Custom GPT Actions and HTTP agents. |
| `POST /mcp/rest/<tool>` | Call one tool with a JSON body and get its structured result. |
| `GET /mcp/health` | Liveness, tool count and supported protocol versions. |
| `GET /llms.txt` | Markdown overview of PrintPal for LLMs, also exposed as the `printpal://llms.txt` resource. |

## Who it is for

- **Agent builders:** Add 3D printing knowledge to a support bot, a print-farm assistant or a classroom tutor.
- **IDE assistants:** Let Copilot, Cursor or Windsurf look up models, docs and print costs while you build hardware projects.
- **Automations:** Call the REST shim from Zapier, n8n or a cron job to price prints or search the library.
- **Researchers and evals:** A stable, public, read-only MCP server is a handy fixture for testing MCP clients.

## Privacy and data

- No account, sign-in or OAuth. The server is public and stateless, so nothing is stored between calls.
- PrintPal only sees the tool inputs the assistant sends (search text, calculator numbers, a model id). It does not see your conversation.
- No personal data is collected and nothing is used for AI training.
- Links back to printpal.io carry a `utm_source` tag so we can see which assistant sent the visit; no identifier is attached.
- Your optional API key is only sent to printpal.io and only unlocks credit-based AI generation.

## FAQ

### What is the PrintPal MCP server?

It is a free, public Model Context Protocol server at https://printpal.io/mcp that gives AI assistants 16 tools for 3D printing: model search, print-cost and calibration calculators, a cited troubleshooting wiki, Arduino and ESP32 build guides, and hand-offs to PrintPal's AI 3D generator and AI CAD agent. It is listed in the official MCP Registry as io.printpal/printpal.

### Does the PrintPal MCP server need authentication?

No. Every tool works anonymously. An optional Authorization: Bearer header with a PrintPal API key unlocks direct AI 3D generation and generation status checks, billed to your PrintPal credits.

### Which MCP clients does it work with?

Any client that supports remote Streamable HTTP servers, including ChatGPT, Claude.ai, Claude Desktop, Claude Code, Gemini CLI, Cursor, VS Code with GitHub Copilot and Windsurf. Clients limited to stdio can use npx mcp-remote https://printpal.io/mcp.

### Does it use SSE?

No. The server is stateless Streamable HTTP and always answers with plain JSON. GET /mcp returns 405 because it does not open a server-to-client stream, which the specification allows.

### Can I call the tools without an MCP client?

Yes. Each tool is available at POST https://printpal.io/mcp/rest/<tool> with a JSON body, and https://printpal.io/mcp/openapi.json describes them in OpenAPI 3.1 for Custom GPT Actions and other HTTP callers.

### Is the PrintPal MCP server free?

Yes. Only direct AI 3D generation costs PrintPal credits, and only when you send your own API key. Without a key, generate_3d_model returns a prefilled link to printpal.io instead.

### Does it store my data?

No. The server is stateless and keeps no session. It only receives the tool arguments your client sends, collects no personal data and does not use requests for training.

## Related integrations

- [PrintPal for Claude](https://printpal.io/integrations/claude): A remote MCP connector for Claude.ai, Claude Desktop and Claude Code with models, calculators, a cited wiki and CAD hand-off.
- [PrintPal for ChatGPT](https://printpal.io/integrations/chatgpt): Search printable models, price prints, fix failed prints and hand off to AI 3D or CAD design, right inside ChatGPT.
- [PrintPal for Cursor](https://printpal.io/integrations/cursor): Download printable models into your repo, write printable OpenSCAD, check meshes and price G-code from the Cursor agent.
- [PrintPal for Gemini](https://printpal.io/integrations/gemini): Use PrintPal as a custom app in Gemini, in the Gemini CLI, or in agents built with Google's Agent Development Kit.

## More

- All integrations: https://printpal.io/integrations
- PrintPal for LLMs: https://printpal.io/llms.txt