com.fabtally/slicer — Model Context Protocol (MCP) Server

The com.fabtally/slicer MCP server provides real 3D-print slicing along with quoting and DFM. It supports quoting, DFM, and printer-related workflows, and notes that tools are free for these tasks. It also indicates that heavier tooling is provided via x402/USDC.

🛠️ Key Features

Real 3D-print slicing
Quoting
DFM (design for manufacturing)
Printer-related support

🚀 Use Cases

Generate slice outputs for 3D printing
Produce quotes tied to print/production needs
Provide DFM guidance for manufacturability
Select or evaluate printers for the print workflow

⚡ Developer Benefits

Integrates slicing, quoting, and DFM into a single MCP server
Clear separation between free tasks and heavier tooling (x402/USDC)

⚠️ Limitations

“Heavy tools” are described as requiring x402/USDC; the scope of what is free is limited to the mentioned quoting/DFM/printer tasks

FabTally MCP Server

The first MCP server for real FDM 3D-printing slicing, quoting, and DFM / printability analysis. Every other 3D-printing MCP just drives a printer (OctoPrint, Bambu). None of them slice, quote, or run design-for-manufacturability checks — FabTally does.

It fronts the FabTally agent API (https://fabtally.com), which runs a production slicing engine against 12 calibrated FDM printer profiles and 12 filament materials, and exposes it as MCP tools so any MCP-capable agent (Claude Desktop, Cursor, custom agents) can discover and call it.

Two-angle design. A human at a keyboard (Claude Desktop, ChatGPT Desktop — no crypto wallet) gets real answers with zero payment from the everyday tools: list_printers, check_printability, analyze_model, get_print_quote. These call FabTally's free, rate-limited public endpoints. An autonomous agent with a wallet gets the heavier/exact tools — optimize_orientation, slice_model, and the full (full=true) DFM report — metered over x402 (USDC on Base). With no payment supplied, those return the x402 challenge (price, network, asset, payTo) so the calling agent knows the cost and can pay and retry.
This server holds no private key and persists no models. It only relays calls to https://fabtally.com/...; uploaded models are streamed to the slicer, never stored.

Tools

Tool	Price	What it does
`list_printers`	free	Live 12-printer fleet (id, bed, nozzle), 12 materials, and x402 pricing tiers. Call this first.
`check_printability`	free / premium $0.01	DFM/printability report. Free geometry preview: printable verdict, watertight, wall-thickness estimate, overhang/support heuristic, fits-on-bed. `full=true` → premium, x402-metered full report with exact slice-derived support & material deltas.
`analyze_model`	free	Geometry preview, no payment: bounding box (mm), volume (cm³), triangle count, watertight, fits-on-bed, plus a printable-so-far verdict as a bonus.
`get_print_quote`	free (rate-limited)	Slicer-accurate FDM price quote: print time, filament grams, priced quote with volume discounts. Supports optional bring-your-own pricing (`currency`, `machine_rate_per_hour`, `margin`, `setup_fee`, `minimum_price`, `material_cost_per_kg`, `markup_percent`) — omit for FabTally's hobbyist defaults.
`optimize_orientation`	premium, x402-metered $0.02	Slices up to 4 orientations and recommends the one using the least support material (exact), with savings vs as-is. For autonomous agents with a wallet — unlimited, machine-speed.
`slice_model`	premium, x402-metered $0.005–$0.02	Full slice on any printer: time, filament, layers, geometry. Optional preview PNG (+$0.005) and/or G-code (+$0.01). For autonomous agents with a wallet.

The free tools are rate-limited public endpoints — fine for a human exploring a design, not for high-volume or production integrations. For unlimited, machine-speed access, an autonomous agent with a wallet can pay per call via x402: the premium tools above, or check_printability with full=true for the exact (slice-derived) DFM report.

The 12 printers

id	printer	bed X×Y×Z (mm)	nozzle
`elegoo-neptune4-max`	Elegoo Neptune 4 Max	420×420×480	0.4
`bambu-a1`	Bambu Lab A1	256×256×256	0.4
`bambu-a1-mini`	Bambu Lab A1 mini	180×180×180	0.4
`bambu-p1s`	Bambu Lab P1S	256×256×250	0.4
`bambu-x1c`	Bambu Lab X1 Carbon	256×256×250	0.4
`prusa-mk4`	Prusa MK4	250×210×220	0.4
`prusa-mini`	Prusa MINI	180×180×180	0.4
`ender3-v3`	Creality Ender-3 V3	220×220×250	0.4
`creality-k1`	Creality K1	220×220×250	0.4
`creality-k1-max`	Creality K1 Max	300×300×300	0.4
`voron-24-350`	Voron 2.4 350	350×350×325	0.4
`anycubic-kobra2`	Anycubic Kobra 2	220×220×250	0.4

Materials: pla, pla-cf, petg, petg-cf, abs, abs-cf, asa, asa-cf, nylon, pc, pet, tpu (PLA/PETG/ABS/ASA + carbon-fiber variants, Nylon, PC, PET, TPU). list_printers always returns the authoritative live list.

Supplying a model file

MCP tools can't take raw file uploads, so every model-consuming tool accepts the model two ways — pick one:

model_url (preferred for local files) — a public https URL to an STL / 3MF / OBJ / PLY / STEP file. The server fetches it. (Try https://fabtally.com/sample-cube-20mm.stl.) Got a file on your machine — Claude Desktop, ChatGPT Desktop? Drop it at https://fabtally.com/upload (no account, drag-and-drop) to get a short-lived URL back (auto-deletes in ~2 hours, nothing kept), then pass that URL as model_url. That page also has a "Get quote now" button for an instant human-readable quote with zero MCP involved.
model_base64 + filename — the raw file bytes, base64-encoded, plus a filename (e.g. "cube.stl") so the file type is known. Only reliable for small files (roughly <50KB). MCP clients truncate large inline tool-call arguments, so a real STL sent this way can silently arrive as a corrupted fragment and produce garbage results (wrong dimensions, bogus quotes) with no error. For anything bigger, use model_url via the upload bridge above.

Example tool calls

jsonc

// 1) Discover printers/materials/pricing (free)
{ "name": "list_printers", "arguments": {} }

// 2) Free printability check on a hosted model
{ "name": "check_printability",
  "arguments": { "model_url": "https://fabtally.com/sample-cube-20mm.stl" } }

// 3) Full DFM report (premium, x402-metered; returns x402 challenge unless x_payment is supplied)
{ "name": "check_printability",
  "arguments": { "model_url": "https://example.com/bracket.stl",
                 "full": true, "printer": "bambu-p1s", "material": "petg" } }

// 4) Price quote, base64 model, 10 parts (free, real result, no payment)
{ "name": "get_print_quote",
  "arguments": { "model_base64": "<...>", "filename": "part.stl",
                 "material": "pla", "quantity": 10 } }

// 5) Least-support orientation (premium, x402-metered, $0.02)
{ "name": "optimize_orientation",
  "arguments": { "model_url": "https://example.com/handle.stl", "printer": "prusa-mk4" } }

// 6) Slice with a preview PNG (premium, x402-metered tier, $0.01)
{ "name": "slice_model",
  "arguments": { "model_url": "https://example.com/gear.stl",
                 "printer": "voron-24-350", "material": "abs",
                 "quality": "standard", "include_preview": true } }

Install

bash

cd fabtally-mcp-server
npm install

Run (stdio — primary)

bash

node index.js
# or, after `npm install -g .`:  fabtally-mcp

The server speaks MCP over stdio. Point your MCP client at it.

Claude Desktop / MCP client config

json

{
  "mcpServers": {
    "fabtally": {
      "command": "node",
      "args": ["/absolute/path/to/fabtally-mcp-server/index.js"]
    }
  }
}

Run (Streamable HTTP — optional)

bash

MCP_HTTP_PORT=8103 node http.js
# POST MCP JSON-RPC messages to http://127.0.0.1:8103/mcp   (stateless)

Configuration

Env var	Default	Purpose
`FABTALLY_BASE`	`https://fabtally.com`	Base origin of the FabTally API.
`MCP_HTTP_PORT`	`8103`	Port for the optional HTTP transport (`http.js`).
`MCP_HTTP_HOST`	`127.0.0.1`	Bind address for the HTTP transport.

How paid calls work (x402)

Call a paid tool (or check_printability with full: true) without x_payment. You get { "payment_required": true, "http_status": 402, "challenge": { ... } } containing the x402 accepts entry (scheme exact, network eip155:8453 = Base, asset USDC, atomic amount, payTo).
Build an x402 payment authorization (EIP-3009 transferWithAuthorization to payTo) for that entry using your x402 client / wallet.
Call the tool again with the resulting token in the x_payment argument. The server forwards it as the X-PAYMENT header and returns the actual result.

Free discovery is always at GET https://fabtally.com/agent/overview; the OpenAPI contract at https://fabtally.com/openapi.json; x402 discovery at https://fabtally.com/.well-known/x402.

Test

bash

node smoke-test.mjs   # lists tools, calls list_printers + check_printability, checks paid 402s

License

MIT · Sunstone Soft · https://fabtally.com

model_url	string	optional	Public https URL to the 3D model file (STL, 3MF, OBJ, PLY, or STEP). The server fetches it. Use this OR model_base64.
model_base64	string	optional	Base64-encoded model file bytes (STL/3MF/OBJ/PLY/STEP), an alternative to model_url for inline data. Provide `filename` too.
filename	string	optional	File name incl. extension, e.g. 'bracket.stl'. Sets the file type; required with model_base64.
x_payment	string	optional	x402 payment payload (base64) for a PAID tool/mode. If supplied it is forwarded as the X-PAYMENT header to settle the call and return the real result instead of a 402 challenge. Omit to get the price challenge first.
full	boolean	optional	false (default) = FREE geometry-only preview via /agent/v1/dfm-preview. true = premium, x402-metered full DFM report ($0.01) with exact slice-derived support & material deltas via /agent/v1/dfm (returns x402 challenge unless x_payment is supplied).
printer	string	optional	3D printer id from list_printers (elegoo-neptune4-max, bambu-a1, bambu-a1-mini, bambu-p1s, bambu-x1c, prusa-mk4, prusa-mini, ender3-v3, creality-k1, creality-k1-max, voron-24-350, anycubic-kobra2). Default elegoo-neptune4-max.
material	string	optional	Filament/material id (pla, pla-cf, petg, petg-cf, abs, abs-cf, asa, asa-cf, nylon, pc, pet, tpu). Default pla.
quality	string	optional	Print quality preset: draft 0.28mm \| standard 0.20mm \| fine 0.12mm layer height.
layer_height	number	optional	Explicit layer height in mm (0.04-0.6); overrides `quality` if both are given.
infill_percent	number	optional	Sparse infill density percent (0-100). Used for the material-saving delta in a full DFM report.

model_url	string	optional	Public https URL to the 3D model file (STL, 3MF, OBJ, PLY, or STEP). The server fetches it. Use this OR model_base64.
model_base64	string	optional	Base64-encoded model file bytes (STL/3MF/OBJ/PLY/STEP), an alternative to model_url for inline data. Provide `filename` too.
filename	string	optional	File name incl. extension, e.g. 'bracket.stl'. Sets the file type; required with model_base64.
x_payment	string	optional	x402 payment payload (base64) for a PAID tool/mode. If supplied it is forwarded as the X-PAYMENT header to settle the call and return the real result instead of a 402 challenge. Omit to get the price challenge first.
printer	string	optional	3D printer id from list_printers (elegoo-neptune4-max, bambu-a1, bambu-a1-mini, bambu-p1s, bambu-x1c, prusa-mk4, prusa-mini, ender3-v3, creality-k1, creality-k1-max, voron-24-350, anycubic-kobra2). Default elegoo-neptune4-max.
material	string	optional	Filament/material id (pla, pla-cf, petg, petg-cf, abs, abs-cf, asa, asa-cf, nylon, pc, pet, tpu). Default pla.
quality	string	optional	Print quality preset: draft 0.28mm \| standard 0.20mm \| fine 0.12mm layer height.
layer_height	number	optional	Explicit layer height in mm (0.04-0.6); overrides `quality` if both are given.
infill_percent	number	optional	Sparse infill density percent (0-100). Used for the material-saving delta in a full DFM report.

model_url	string	optional	Public https URL to the 3D model file (STL, 3MF, OBJ, PLY, or STEP). The server fetches it. Use this OR model_base64.
model_base64	string	optional	Base64-encoded model file bytes (STL/3MF/OBJ/PLY/STEP), an alternative to model_url for inline data. Provide `filename` too.
filename	string	optional	File name incl. extension, e.g. 'bracket.stl'. Sets the file type; required with model_base64.
printer	string	optional	3D printer id from list_printers (elegoo-neptune4-max, bambu-a1, bambu-a1-mini, bambu-p1s, bambu-x1c, prusa-mk4, prusa-mini, ender3-v3, creality-k1, creality-k1-max, voron-24-350, anycubic-kobra2). Default elegoo-neptune4-max.
material	string	optional	Filament/material id (pla, pla-cf, petg, petg-cf, abs, abs-cf, asa, asa-cf, nylon, pc, pet, tpu). Default pla.
quantity	integer	optional	Number of parts (1-10000). Volume discounts apply automatically. Default 1.
quality	string	optional	Print quality preset: draft 0.28mm \| standard 0.20mm \| fine 0.12mm layer height.
layer_height	number	optional	Explicit layer height in mm (0.04-0.6); overrides `quality` if both are given.
infill_percent	number	optional	Sparse infill density percent (0-100). Used for the material-saving delta in a full DFM report.
supports	string	optional	Support generation style.
currency	string	optional	Bring-your-own pricing: 2-8 letter currency code (e.g. USD, EUR). Default USD.
machine_rate_per_hour	number	optional	Bring-your-own pricing: machine time cost per hour, in `currency`. Default FabTally's rate.
margin	number	optional	Bring-your-own pricing: fractional margin on top of cost, e.g. 0.3 = 30%. Default FabTally's margin.
setup_fee	number	optional	Bring-your-own pricing: flat per-quote setup fee, in `currency`. Default FabTally's fee.
minimum_price	number	optional	Bring-your-own pricing: price floor per unit, in `currency`. Default FabTally's minimum.
material_cost_per_kg	number	optional	Bring-your-own pricing: override the material's $/kg cost. Default FabTally's material pricing.
markup_percent	number	optional	Bring-your-own pricing: extra percent markup applied on top of margin. Default 0.

model_url	string	optional	Public https URL to the 3D model file (STL, 3MF, OBJ, PLY, or STEP). The server fetches it. Use this OR model_base64.
model_base64	string	optional	Base64-encoded model file bytes (STL/3MF/OBJ/PLY/STEP), an alternative to model_url for inline data. Provide `filename` too.
filename	string	optional	File name incl. extension, e.g. 'bracket.stl'. Sets the file type; required with model_base64.
x_payment	string	optional	x402 payment payload (base64) for a PAID tool/mode. If supplied it is forwarded as the X-PAYMENT header to settle the call and return the real result instead of a 402 challenge. Omit to get the price challenge first.
printer	string	optional	3D printer id from list_printers (elegoo-neptune4-max, bambu-a1, bambu-a1-mini, bambu-p1s, bambu-x1c, prusa-mk4, prusa-mini, ender3-v3, creality-k1, creality-k1-max, voron-24-350, anycubic-kobra2). Default elegoo-neptune4-max.
material	string	optional	Filament/material id (pla, pla-cf, petg, petg-cf, abs, abs-cf, asa, asa-cf, nylon, pc, pet, tpu). Default pla.
quality	string	optional	Print quality preset: draft 0.28mm \| standard 0.20mm \| fine 0.12mm layer height.
layer_height	number	optional	Explicit layer height in mm (0.04-0.6); overrides `quality` if both are given.
infill_percent	number	optional	Sparse infill density 0-100.
supports	string	optional	Support generation style.
include_preview	boolean	optional	Add a base64 PNG preview render of the sliced model (raises the price tier).
include_gcode	boolean	optional	Add the sliced G-code, gzip+base64 (raises the price tier).

FabTally 3D-Print Slicer, Quote & DFM

com.fabtally/slicer — Model Context Protocol (MCP) Server

🛠️ Key Features

🚀 Use Cases

⚡ Developer Benefits

⚠️ Limitations

list_printers

check_printability

optimize_orientation

analyze_model

get_print_quote

slice_model

FabTally MCP Server

Tools

The 12 printers

Supplying a model file

Example tool calls

Install

Run (stdio — primary)

Claude Desktop / MCP client config

Run (Streamable HTTP — optional)

Configuration

How paid calls work (x402)

Test

License

Install

Remote endpoint