Flow Pack: how to connect
Free tools a UK plumber's or heating engineer's AI assistant uses on the job: water and gas pipe sizing, room by room heat loss with boiler, heat pump and radiator sizes, notifiable work rules, gas safety record checks and emergency triage.
Flow Pack is a remote MCP server: a set of tools your AI assistant can call. You do not open it like a website. You add its address to your AI app once, then just talk to your assistant as normal.
Server address: https://flow-pack.nerolabs.workers.dev/mcp
Sign-in: None. No account, no key and no sign-in: add the address and use it.
Connect it in Claude
- Open Claude (claude.ai or the desktop app) and go to Settings, then Connectors.
- Choose Add custom connector. Name it Flow Pack and paste
https://flow-pack.nerolabs.workers.dev/mcpas the URL. - Save, then turn it on in a chat from the tools menu.
Claude Code: claude mcp add --transport http flow-pack https://flow-pack.nerolabs.workers.dev/mcp
Connect it in ChatGPT
- In ChatGPT go to Settings, then Apps and connectors, then Advanced settings, and switch on Developer mode (needed for any custom connector).
- Back in Apps and connectors, choose Create. Name it Flow Pack, paste
https://flow-pack.nerolabs.workers.dev/mcpas the MCP server URL and pick No authentication. - Tick that you trust the app and press Create. Then pick it from the tools menu in a new chat.
Other MCP apps (Cursor, VS Code, Windsurf, Gemini CLI and more)
Add a remote server with the Streamable HTTP transport. Most apps take a JSON block like this:
{
"mcpServers": {
"flow-pack": { "type": "http", "url": "https://flow-pack.nerolabs.workers.dev/mcp" }
}
}
Three things to try
The tools
| Tool | What it does |
|---|---|
list_capabilities | What Flow Pack can do Lists Flow Pack's tools, what it covers (nations, pipe materials, gases, record types, emergency situations) and what it deliberately does not do. |
size_pipe | Water or gas pipe size, velocity and pressure loss Sizes a hot or cold water pipe, or a low-pressure gas pipe, and shows the working. |
size_heat_source | Room by room heat loss, boiler and heat pump size Works out the heat loss of each room (fabric U x A x delta T plus ventilation 0.33 x air changes x volume x delta T) and the total, then sizes a combi, system or regular boiler, or a heat pump, to the nearest common size. |
size_radiators | Radiator size per room, including at heat pump temperatures For each room's heat loss, works out the rated (delta T 50) radiator output needed at the system's flow and return temperatures, using output = rated x (mean water to air difference / 50) ^ 1.3. |
check_notifiable_work | Is this work notifiable, and who can do it? For plumbing and heating jobs in England or Wales: does it need a Gas Safe registered engineer, an unvented (G3) qualified installer, building regulations notification (Approved Documents G, J, L and others) and a water company notice... |
check_gas_record | Check a gas safety record or commissioning record before issuing it Checks a filled landlord gas safety record (CP12) or a boiler commissioning record and lists errors and warnings: missing required fields, failed tightness, flue, ventilation or safety device checks, CO/CO2 ratio over the limits, gas rate... |
emergency_triage | Emergency triage for leaks, bursts, no heat, gas smell or CO alarm For a homeowner reporting a problem: the safe first steps to do now, what not to do, who to call first (the gas emergency service 0800 111 999 for a gas smell or CO alarm), whether it is a real emergency, and an `urgency` value of routine,... |
trade_profile | Check the plumber or heating engineer's business details Checks the business's own details (Nero Trade Profile v1: trading name, Companies House number, registration scheme and number, postcode, contact) and returns them cleaned, with a stable `nero_trade_ref` computed from the scheme... |
Good to know
- Built for UK plumbers and heating engineers. Every answer shows its working and sources and lists what the trade must check. The trade doing the work stays responsible for it.
- Free forever: no sign-up, no key, no daily cap, no paid plan.
- What is stored and how to delete it: see Privacy.
Support
Email founder@neroengine.com. Say which tool you used and what you asked; we reply within 2 working days.
Nero Engine Group Ltd (company 16521432, England and Wales), trading as Nero Labs. Page updated 12-11-2026.