Spec Driven Development
by formulahendry
MCP Server that facilitates spec-driven development workflows, not just Vibe Coding.
Runs on your computer★ 440MITUpdated 14 months ago
Install
OpenMEP duct sizing
Overview
Description from the maker (original English)
Deterministic HVAC duct sizing at a fixed or Manual D friction rate; grades existing ducts.
PopNx MCP’s three pillars
These three are never merged into one score: opinions, measurements and popularity are different things.
- User voiceiNo reviews yetReviews open together with accounts in a later step
- Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
- UsageiNot measured yet★ –
What you can do with it
We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.
- Connection: Runs on your computer
- Transport: stdio
- Category: Other
Install
Pick the AI app you use, then copy the settings.
Before you install
- Basic checks: 1 of 1 passed
- Runs on your computer with your user’s permissions (files, network, apps).
- The registry lists no key to fill in.
You need
- npmNode.js installed (for the npx command)
Which app do you use?
Pick your app above. We remember it, so next time the button says “Install in …”.
Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json
{
"mcpServers": {
"openmep": {
"command": "npx",
"args": [
"-y",
"@openmep/mcp"
]
}
}
}Run this in your terminal
claude mcp add openmep -- npx -y @openmep/mcpOr copy the settings yourself
Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json
{
"mcpServers": {
"openmep": {
"command": "npx",
"args": [
"-y",
"@openmep/mcp"
]
}
}
}Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.
Or copy the settings yourself
Paste into .vscode/mcp.json in your project
{
"servers": {
"openmep": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"@openmep/mcp"
]
}
}
}Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.
This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.
Your choice stays on this device in a cookie; no account needed.
These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.
What it can do
Runs on your computer; the tool list appears in your AI app after you install it.
Basic checksi
We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 6, 2026
- ✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account samarmstrong, which owns the repo
- … Not checked yet
Still maintained
We have not read this repo from GitHub yet
- … Not checked yet
Has a licence
We have not read this repo from GitHub yet
- – Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
- – Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
- … Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints
Compared with others in Otheri
- More stars than 0% of the other 32484 servers in this category
- Published to the registry more recently than 57% of the other 32484 servers in this category
- Basic checks equal to or better than 100% of the other 32484 servers in this category
Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.
Common questions
Is OpenMEP duct sizing safe?
It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.
What keys or codes does it need?
The registry does not list a required key, though some servers ask you to sign in on first use.
Does it run on my computer or in the cloud?
It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).
Is it still maintained?
The GitHub repo last changed –, and the latest version (0.2.0) reached the registry 30 days ago.
Which apps can use it?
Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Node.js on your computer.
What can I use instead?
In the same category: Spec Driven Development, Remote Desktop Commander, Recta
Alternatives
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Reading a card:★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi
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Runs in the cloud★ 211Updated yesterday
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Recta
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README from the maker
Open the README
Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.
@openmep/mcp
An MCP server that gives any agent OpenMEP's deterministic HVAC duct sizing. No editor, CAD host, account, or network access: the agent describes the ducts, the engine sizes them.
{"mcpServers": { "openmep": { "command": "npx", "args": ["-y", "-p", "@openmep/mcp", "openmep-mcp"] } } }
Claude Code: claude mcp add openmep -- npx -y -p @openmep/mcp openmep-mcp. Requires Node.js 24+. Transport: stdio.
Tools
| Tool | Input | Returns | |
|---|---|---|---|
size_duct | cfm, optional role (main/branch/runout), airflowType (supply/return/exhaust/outside-air), existing section ({diameterIn} or `{shape: rect\ | oval, widthIn, heightIn}`) | Recommended standard round diameter, velocity, friction; for an existing section its circular equivalent and ok/undersized/oversized |
size_duct_network | items: terminals with requiredCfm, segments (optionally with existing and lengthFt), fittings (optionally equivalentLengthFt), equipment, linked by connectedItemRefs; optional fan (externalStaticInWg, componentLossesInWg) | Every loaded segment's CFM, role, recommendation, and grade; with fan, the Manual D design (available static, total effective length, friction rate, governing paths); findings for missing CFM, disconnected terminals, dangling references, mixed systems, undersized and oversized runs, friction rate outside 0.06–0.18 |
Both tools are read-only and idempotent. Invalid input comes back as a tool error naming the field (NetworkInputError [invalid-item]: items[2].requiredCfm: ...) so the model can correct it.
Example prompt that works in a fresh Claude Code session with only this server:
I have a furnace feeding a supply trunk that tees into two runouts: bedroom 1
needs 120 CFM, bedroom 2 needs 90 CFM, and the living room is fed off the trunk
end at 200 CFM. All drawn as 6 inch round. One return grille in the hall at
410 CFM on a 10 inch drop. Is anything undersized?
The agent builds the network in one size_duct_network call and reports 7, 6, and 8 in runouts, an 11 in trunk, and a return drop just under size at 10 in.
Engineering basis and limits
Equal friction at 0.08 in. w.g./100 ft, or at the Manual D rate derived from the blower's available static pressure when fan and lengths are given, with role-based velocity caps per system, rounded up to standard round diameters; see @openmep/hvac-domain for the formula, sources, and what is excluded (fitting losses, static pressure summation, fan selection). Airflow is a design input the server never estimates. Treat results as preliminary sizing for an engineer to review.
The server uses the official MCP TypeScript SDK and speaks the initialize-handshake protocol revisions (through 2025-11-25), which current clients support.
Library
import { createOpenMepServer } from "@openmep/mcp";await createOpenMepServer().connect(transport); // any MCP server transport