Openapi MCP

Name: Openapi MCP
Author: Asthanaji05

by Asthanaji05version 0.1.1i★ –iRuns on your computer

Registry nameio.github.Asthanaji05/openapi-mcp

Install

Overview

Description from the maker (original English)

Turn any OpenAPI 3 spec into a working MCP server. One file, local (stdio) or remote (HTTP).

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?

ClaudeClaude CodeCursorVS CodeChatGPT

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": {
    "openapi": {
      "command": "npx",
      "args": [
        "-y",
        "@asthanaji/openapi-mcp"
      ]
    }
  }
}

Run this in your terminal

claude mcp add openapi -- npx -y @asthanaji/openapi-mcp

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "openapi": {
      "command": "npx",
      "args": [
        "-y",
        "@asthanaji/openapi-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.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "openapi": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@asthanaji/openapi-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 7, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account Asthanaji05, 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 32684 servers in this category
Published to the registry more recently than 60% of the other 32684 servers in this category
Basic checks equal to or better than 100% of the other 32684 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 Openapi MCP 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 (0.1.1) reached the registry 26 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, Master CSS

Alternatives

Servers in the same category from other makers, sorted by stars.

Reading a card:★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi

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

Remote Desktop Commander

by desktop-commander

Remote Desktop Commander: use files, terminal and processes on your own computers from any AI app.

Runs in the cloud★ 211Updated 2 days ago

Install

Master CSS

by master-co

Inspect Master CSS classes, generated CSS, and project stylesheets from your AI client.

Runs on your computerUpdated today

Install

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.

OpenAPI MCP

Turn any OpenAPI 3 spec into a working MCP server. One file, about 130 lines, no dependencies.

node openapi-mcp.mjs https://your-api.com/openapi.json

Every API endpoint becomes a tool that an AI client (Claude, Cursor, etc.) can call. There is no code generation and no per-endpoint files. The spec is read at startup, and the tools are built in memory.

Quick start

Requires Node 18 or newer.

git clone <this-repo>

cd openapi-mcp node openapi-mcp.mjs sample/animechan.openapi.json

It prints openapi-mcp: 4 tools from "Animechan" -> ... and then waits silently for an MCP client. That is normal: it talks JSON-RPC over stdin/stdout and is not meant to be read by humans.

Use it with an AI client

Claude Desktop (local mode)

Add this to ~/Library/Application Support/Claude/claude_desktop_config.json, then restart the app:

"mcpServers": { "animechan": { "command": "node", "args": ["/full/path/openapi-mcp.mjs", "/full/path/animechan.openapi.json"] } } }

If the client can't find node, use the full path from which node.

Claude Code (remote mode)

Start the server, then register it:

MCP_AUTH_TOKEN=secret node openapi-mcp.mjs sample/animechan.openapi.json --http 8787

claude mcp add --transport http animechan http://localhost:8787/mcp \ --header "Authorization: Bearer secret"

Then ask in plain English: "give me a random quote from Naruto".

Two modes

Mode	Command	Use when
Local (stdio)	`node openapi-mcp.mjs`	The client launches the server on your machine
Remote (HTTP)	`node openapi-mcp.mjs --http`	The client connects to a URL, or you want to self-host

In HTTP mode, clients send JSON-RPC messages as POST http://host: /mcp. Put --http last.

Test it by hand:

curl -X POST localhost:8787/mcp -H 'Authorization: Bearer secret' \

-d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}'

Options

node openapi-mcp.mjs <spec-url-or-file> [base-url] [--http <port>]

Argument / env var	What it does
	OpenAPI 3 spec, as a URL or a local file (JSON; YAML needs `npm i yaml`)
`[base-url]`	Overrides the API address. Defaults to `servers[0].url` in the spec
`API_TOKEN`	Your secret for the API. The spec's `securitySchemes` decide where it goes (see Authentication)
`OAUTH_CLIENT_ID`, `OAUTH_CLIENT_SECRET`	OAuth2 client-credentials: the token is fetched and refreshed automatically
`OAUTH_REFRESH_TOKEN`	OAuth2 refresh-token grant (use with the client id and secret)
`OAUTH_TOKEN_URL`, `OAUTH_SCOPE`	Optional: override the `tokenUrl` from the spec, or request a scope
`API_HEADERS`	Extra headers sent on every call, for anything the schemes don't cover. Example: `'{"X-App-Id":"abc"}'`
`TOOL_FILTER`	Regex. Only tools whose name matches are exposed. Example: `'^(get\	list)'` for read-only
`MCP_AUTH_TOKEN`	HTTP mode only. Requires `Authorization: Bearer` on every request

Big APIs can have hundreds of endpoints. Too many tools makes the model choose worse, so use TOOL_FILTER to keep the useful ones.

Authentication

The server reads securitySchemes from the spec and puts your secret in the right place. You only supply the secret as an environment variable:

Spec says	Set	Sent as
`http` / `bearer`	`API_TOKEN=tok`	`Authorization: Bearer tok`
`http` / `basic`	`API_TOKEN=user:pass`	`Authorization: Basic`
`apiKey` in header	`API_TOKEN=key`	The header named in the spec (e.g. `X-Key: key`)
`apiKey` in query	`API_TOKEN=key`	The query parameter named in the spec
`apiKey` in cookie	`API_TOKEN=key`	`Cookie: name=key`
`oauth2` / `openIdConnect`, you already have an access token	`API_TOKEN=token`	`Authorization: Bearer token`
`oauth2`, machine-to-machine	`OAUTH_CLIENT_ID` + `OAUTH_CLIENT_SECRET`	Token fetched from the `tokenUrl`, cached, and renewed before it expires
`oauth2`, you logged in once elsewhere	the two above + `OAUTH_REFRESH_TOKEN`	Access tokens renewed from the refresh token

Example for Claude Desktop:

"mcpServers": { "my-api": { "command": "node", "args": ["/full/path/openapi-mcp.mjs", "https://my-api.com/openapi.json"], "env": { "API_TOKEN": "your-secret" } } } }

Notes:

If the spec declares a security scheme but no credentials are set, a warning is printed to stderr at startup.
If the spec lists several schemes, the first one in the top-level security list is used (or the first one defined). Per-endpoint security overrides are not applied, so the secret is sent on every call.
OAuth client credentials are sent as HTTP Basic auth to the token endpoint.
The OAuth browser login (authorization-code flow) is not built in. Get a token or refresh token once with your provider's tools, then pass it in.
If a provider rotates refresh tokens, the new one is kept in memory only, so it is lost on restart.

How it works

Load the spec and resolve $ref pointers.
Build tools: each operation becomes one MCP tool. operationId is the name, summary the description, and parameters plus request body the input schema.
Call: a tool call makes the real HTTP request and returns HTTP followed by the response body (cut at 50,000 characters).
Serve the tools over JSON-RPC 2.0, via stdio or HTTP.

APIs without an OpenAPI spec

Many small public APIs only have HTML docs. For those, write a small spec by hand (see sample/animechan.openapi.json, 4 tools in about 35 lines), then run it the same way.

Limitations

OpenAPI 3 only. Convert Swagger 2.0 specs first.
JSON request bodies only. No file uploads.
Auth: bearer, basic, API keys, and OAuth2 client-credentials or refresh-token. There is no interactive OAuth login, and one scheme is used per API.
HTTP mode speaks plain HTTP (put HTTPS in front when deploying) and has no streaming, batch requests, or OAuth for clients connecting to the server (it only supports the MCP_AUTH_TOKEN bearer token). Some remote clients may require these.
HTTP mode speaks plain HTTP (put HTTPS in front when deploying) and has no streaming, batch requests, or OAuth. Some remote clients may require these.
If you deploy remotely, every user shares your server's IP, so upstream rate limits apply to all of them. Set MCP_AUTH_TOKEN, or anyone who finds the URL can use your API key.

Contributing

Issues and pull requests are welcome. The goal is to stay small and readable, so please keep new features to a few lines each.

Openapi MCP

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Otheri

Common questions

Alternatives

Spec Driven Development

Remote Desktop Commander

Master CSS

README from the maker

OpenAPI MCP

Quick start

Use it with an AI client

Claude Desktop (local mode)

Claude Code (remote mode)

Two modes

Options

Authentication

How it works

APIs without an OpenAPI spec

Limitations

Contributing