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Capabilities Txt Registry

by capabilityhostprotocolversion 0.1.0i★ –iRuns in the cloud
Registry nameio.github.capabilityhostprotocol/capabilities-txt-registry

Install

Overview

Description from the maker (original English)

Discover what websites across the agentic web can do — query the capabilities.txt registry.

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

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.

Install

Pick the AI app you use, then copy the settings.

Before you install

  • Basic checks: 1 of 1 passed
  • Runs on the maker’s server: what you ask it goes through their server.
  • The registry lists no key to fill in.

You need

Which app do you use?

Pick your app above. We remember it, so next time the button says “Install in …”.

Works in Claude on the web, desktop and mobile:

  1. Open Settings → Connectors
  2. Press Add custom connector
  3. Paste the address below and press Add
  4. If it asks you to sign in, sign in with the maker
SettingsConnectors1+ Add2https://…3
https://capabilitiestxt.org/api/mcp

Run this in your terminal

claude mcp add --transport http capabilities-txt-registry https://capabilitiestxt.org/api/mcp

Open in Cursor

Or copy the settings yourself

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

{
  "mcpServers": {
    "capabilities-txt-registry": {
      "url": "https://capabilitiestxt.org/api/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": {
    "capabilities-txt-registry": {
      "type": "http",
      "url": "https://capabilitiestxt.org/api/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.

ChatGPT connects only to servers on the internet:

  1. Open ChatGPT on the web → Settings → Connectors (Apps)
  2. Press Create or Add (some plans need Developer mode under Advanced first)
  3. Paste the address below, give it a name and save
  4. If it asks you to sign in, sign in with the maker
SettingsConnectors1+ Create2https://…3
https://capabilitiestxt.org/api/mcp

Menu names can differ slightly by plan and over time.

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

We have not read this server’s tool list yet; we check endpoints in rotation.

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 capabilityhostprotocol, 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 checked yet

    Endpoint responds

    Not checked yet; we check endpoints in rotation

  • … Not checked yet

    Sign-in with OAuth

    Not checked yet; we check endpoints in rotation

  • … Not checked yet

    No hidden instructions in tool descriptions

    Not checked yet; we read the tool list when we check the endpoint

Compared with others in Otheri

  • More stars than 0% of the other 32466 servers in this category
  • Published to the registry more recently than 14% of the other 32466 servers in this category
  • Basic checks equal to or better than 100% of the other 32466 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 Capabilities Txt Registry 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 in the maker’s cloud. Connect over the internet with nothing to install, but what you send passes through the maker’s servers.

Is it still maintained?

The GitHub repo last changed –, and the latest version (0.1.0) reached the registry 4 months ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. It connects by URL, so apps that accept remote MCP servers work too, such as ChatGPT in developer mode.

What can I use instead?

In the same category: Spec Driven Development, Remote Desktop Commander, HotCodePush

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 yesterday
Install

HotCodePush

by hotcodepush-team

Manage over-the-air (OTA) updates for React Native, Expo, Capacitor and Cordova apps.

Runs in the cloudUpdated 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.

capabilities.txt

A simple, open convention for a website to declare what it can do — the

capabilities an agent can discover and invoke — at a well-known location.

The web taught machines to read in layers. robots.txt says what a crawler *may access*. sitemap.xml says what *exists*. llms.txt says what's *worth reading*. Each answers one narrow question for an automated reader.

None of them answers the question agents now ask: **what can this host actually *do*?**

Agents have stopped only *reading* the web and started *acting* on it. An agent that lands on your site can summarize your docs — but it has no standard way to discover that you expose a "create support ticket" capability, a "check inventory" capability, or "start a return," and how to call them. Today that happens through bespoke, one-vendor-at-a-time integrations.

capabilities.txt is the missing layer: a public, well-known file where a host declares the capabilities it offers, so any agent can discover what it can do.

It is deliberately small. llms.txt worked because you could adopt it in an afternoon. capabilities.txt follows the same rule.

The two forms

A host publishes one or both:

  • `/capabilities.txt` — human- and agent-readable markdown: capabilities grouped by category, each with an id, version, and one-line description.
  • `/.well-known/capabilities.json` — the structured form: an array of capability references, each resolvable to a full descriptor.

The markdown form is for discovery and reading. The JSON form is for machines that want structure. Publishing the markdown form alone is a perfectly good start.

Format (/capabilities.txt)

# capabilities.txt

One sentence: what this host is and what kind of capabilities it offers.

Structured form: https://example.com/.well-known/capabilities.json

##

( )
  • (v ) —
  • (v ) —

Rules, kept minimal:

  1. Line 1 is # capabilities.txt.
  2. A blockquote (>) summary follows: one sentence on what the host offers, plus optional links (the JSON form, docs, an invocation endpoint).
  3. `##` headings group capabilities by category (free-form, your choice).
  4. `###` headings name a group, optionally with a stable (group-id).
  5. Each capability is a list item: a stable capability-id, an optional (v ), and a short — description.
  6. It's just markdown. If a human can read it and an agent can parse it, it's valid.

Structured form (/.well-known/capabilities.json)

{

"version": "1", "capabilities": [ { "id": "support.create_ticket", "version": "1.2.0", "description": "Open a support ticket", "descriptor": "https://example.com/.well-known/capabilities/support.create_ticket.json" } ] }

Each entry is a reference; descriptor (optional) points to a full machine-readable description of inputs, permissions, and how to invoke.

Where it sits among the standards

FileAnswersFor
robots.txtWhat may a crawler access?Crawlers
sitemap.xmlWhat pages exist?Search engines
llms.txtWhat's worth reading?LLMs reading
`capabilities.txt`**What can this host *do*?**Agents acting

It is not a replacement for MCP or an API spec. The Model Context Protocol is a stateful connection-and-invocation protocol; OpenAPI describes an HTTP API. capabilities.txt is the layer *before* invocation — a static, public, crawlable advertisement an agent (or a search engine) can read with no live connection, that points to your MCP server, HTTP API, or other endpoint for the actual call. Discovery and invocation are different jobs. capabilities.txt does discovery; it hands off invocation.

Adopt it

Fastest (no spec): copy the prompt at capabilitiestxt.org/implement and hand it to your AI coding agent — it writes your capabilities.txt from your code.

Have an OpenAPI spec? Generate it in your browser (paste the URL) — or keep it current automatically in CI with the GitHub Action:

- uses: capabilityhostprotocol/capabilities-txt/action@main

with: openapi: https://api.yoursite.com/openapi.json output: public/capabilities.txt

Then check it at capabilitiestxt.org/submit for a grade, fixes, and a badge — and it’s discoverable in the directory + map.

By hand:

  1. List the capabilities your site exposes (or could).
  2. Write them into /capabilities.txt using the format above.
  3. Optionally publish /.well-known/capabilities.json.
  4. Add yourself to adopters.md with a pull request.

Already have an OpenAPI spec? Generate it — no manual authoring:

python tools/from_openapi.py https://api.yoursite.com/openapi.json > capabilities.txt

python tools/validate.py capabilities.txt # check it

Working references — a real, live capabilities.txt plus illustrative templates across markets (e-commerce, support, banking, healthcare, dev platform) — are in examples/. The tools in tools/ generate and validate files.

Where this goes next

Discovery is the first step. Once an agent knows *what* you can do, the next questions are *may I*, *what happened*, and *can I prove it* — invocation, governance, and evidence. Those are defined by the Capability Host Protocol (CHP), an open protocol for which capabilities.txt is the natural public face. You can adopt capabilities.txt on its own; CHP is where it leads if you need the rest.

Status & license

This is a proposal with a working reference, not a finished standard — and it's better for your feedback. Open an issue or PR.

  • Specification & site text (README.md, index.html, SPEC.md): CC BY 4.0 — see LICENSE-DOCS.
  • Tooling (tools/): Apache-2.0 — see LICENSE.
  • "capabilities.txt" is a free, open convention — use it freely. (No trademark.)

Copyright © 2026 Project Auxo, Inc. and contributors.

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