compatsy-mcp

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

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.

Related MCP server: McMaster-Carr MCP Server

Tools

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: support@compatsy.com