compatsy 3D printing

compatsy-mcp

compatsy answers "does this part fit that machine, and where is it in stock?" Each category has its own MCP endpoint:

Category	Covers	Endpoint
3D printing	printers, nozzles, hotends, build plates, filament, enclosures	https://compatsy.com/3d-printing/mcp
Home espresso	machines, tampers, puck screens, distribution tools, dosing funnels, baskets	https://compatsy.com/home-espresso/mcp

Specs carry their source and confidence, fit verdicts cite the rule that decided them, and prices come with the time they were last verified.

This repo is the quickstart for the hosted MCP server. Nothing runs locally except an optional stdio bridge.

Connect

Remote (preferred). Any client that supports Streamable HTTP:

{ "mcpServers": { "compatsy-3d-printing": { "url": "https://compatsy.com/3d-printing/mcp" } } }

stdio via npx. For clients that only launch local servers:

{ "mcpServers": { "compatsy-espresso": { "command": "npx", "args": ["-y", "github:elliot-rosen/compatsy-mcp"], "env": { "COMPATSY_MCP_URL": "https://compatsy.com/home-espresso/mcp" } } } }

Claude Code: claude mcp add --transport http compatsy-3d-printing https://compatsy.com/3d-printing/mcp

No account or key. Calls are rate limited per session. The bridge defaults to https://compatsy.com/mcp (3D printing); set COMPATSY_MCP_URL to another endpoint from the table.

Tools

Tool	What it does	Read-only
search_products	Find products by name or category plus spec filters	yes
get_product	Full specs with source and confidence, every offer with verified time	yes
compare	Side-by-side spec table for 2 to 10 products	yes
check_fit	Verdict for a part and a machine, with the rule id and version, or the missing fields	yes
check_stock	Price and availability per merchant, re-verified when over an hour old	yes
report_issue	Flag a wrong spec, price or verdict. Reports never edit facts	no

Example calls

{"name": "search_products", "arguments": {"query": "hardened nozzle 0.4", "category": "nozzle", "limit": 5}}
{"name": "get_product", "arguments": {"product_id": "prusa-mk4s"}}
{"name": "compare", "arguments": {"product_ids": ["bambu-lab-p1s", "prusa-core-one"]}}
{"name": "check_fit", "arguments": {"subject_id": "<nozzle id from search_products>", "target_id": "prusa-mk4s"}}
{"name": "check_stock", "arguments": {"product_id": "prusa-mk4s"}}
{"name": "report_issue", "arguments": {"entity_type": "product", "entity_id": "prusa-mk4s", "field": "nozzle_thread", "claim": "MK4S uses the Nextruder thread"}}

Example prompts that use them well:

• "Will a V6 nozzle fit my Prusa MK4S? If it needs an adapter, say which."
• "Which hardened 0.6 mm nozzles fit a Bambu Lab P1S, cheapest in stock first?"
• "Compare the Core One and the P1S on build volume and enclosure."
• "Which puck screens fit a Breville Barista Express, in stock?"

Verdicts

fits, fits_with_adapter, does_not_fit or unknown. Unknown is an answer: it lists the spec fields that are missing rather than guessing. Every rule needs two independent sources, one from the manufacturer, before it can decide anything.

Editor rules

rules/cursor.mdc and rules/windsurf.md tell Cursor or Windsurf agents when to call compatsy instead of guessing fitment from memory.

Links

• Methodology: https://compatsy.com/3d-printing/methodology and https://compatsy.com/home-espresso/methodology
• Open data: https://compatsy.com/data
• Privacy: https://compatsy.com/3d-printing/privacy
• OpenAPI: https://compatsy.com/api/v1/openapi.json
• Support: [email protected]