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Flow FrameworkOpen-source, one codebase for every chat Unified APIiMessage, WhatsApp and Telegram Flow CloudHosting, tests and observability

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Claude plugins · MCP

Build a Claude plugin from your product’s tools.

Claude reaches other products through connectors, which are remote MCP servers. Write what your product does as tools in Flow, and Claude can use it, with each user signed in to their own account.

Start building free Flow Framework on GitHub

Add it as a custom connector today; submit it to the Connectors Directory when ready.

What you can build

Where knowledge work
meets your product.

SaaS

Your product inside Claude’s work

People ask Claude about their pipeline, their tickets or their analytics, and it answers from your product with their permissions. Asana, Figma, Canva, Slack and monday.com launched interactive connectors.

Analytics

Answers from live data

Questions turn into queries.

Support

Tickets triaged in chat

Read, tag and reply with the right access.

Ops

Actions with a confirm step

Writes marked as such, approved by the user.

Brand examples are illustrations of what could be built, not those companies' products.

The usual way vs. Flow

A Claude connector by hand
is mostly auth and review prep.

Building it yourself~3–4 weeks

  1. MCP server, tool titles and hints 2–3 days
  2. Remote transport and hosting 1–2 days
  3. OAuth, metadata, client registration 1–2 weeks
  4. Test with Inspector and Claude 1–2 days
  5. Test account, screenshots, submission 1–2 days

And ChatGPT, Muse and coding agents each need the work again.

With Flow Frameworkan afternoon

  1. Create the project1 min
  2. Write your tools1–2 hrs
  3. Test, add as a custom connector20 min
tools/find-deals.ts
import { tool } from "@flow-engineer/flow";
import { z } from "zod";

export default tool({
  name: "find_deals",
  description: "Find the user’s deals by stage, owner or amount.",
  input: z.object({ stage: z.string().optional(), min: z.number().optional() }),
  run: async (q, { user }) => crm.deals.search(user, q),
});

How Flow works

Write it once. Ship it to Claude and everywhere else.

  • Tools become your appThe same typed tools are served as an MCP server and a CLI. No transport, schema or protocol code.
  • Each user signs inFlow handles each user’s sign-in, so the assistant only reaches what that person can.
  • Tested and tracedSimulated users check which prompts should and should not call your tools, and every call is traced.

Get started

How to build a Claude plugin with Flow.

  1. Create a Flow project

    Run npx @flow-engineer/flow new my-agent, or ask Claude Code or Codex to set it up. You get one folder: the agent’s instructions, its tools, its skills and its tests.

  2. Write what it can do as tools

    Each job is a TypeScript function with a typed input that calls your API: check an order, book a slot, find a deal. No protocol code.

  3. Test it on simulated users

    Run npx @flow-engineer/flow test. Simulated users try the scenarios that matter, including people who change their mind or ask for something your agent should refuse.

  4. Add it to Claude

    Flow serves your tools as a remote MCP server with each user’s sign-in. In Claude, open Settings → Connectors, add a custom connector and paste the address.

  5. Submit to the Connectors Directory

    Submit at Anthropic’s directory with a test account, tool descriptions and screenshots. The same project ships to ChatGPT too.

terminal
$ npx @flow-engineer/flow new my-agent
$ cd my-agent
$ npx @flow-engineer/flow test
✓ 24 scenarios passing

Guide

Claude connectors, MCP and skills, explained.

What is a Claude connector?

A connector lets Claude use another product: read its data and take actions in it. Under the hood it is an MCP server. Remote connectors run on HTTPS and work in Claude on the web, desktop and mobile; users add them in Settings → Connectors or install them from the Connectors Directory.

How do I add a custom connector to Claude?

On a paid plan, open Settings → Connectors, choose add custom connector and paste the MCP server’s URL. If it needs sign-in, Claude opens the product’s login. On Team and Enterprise, an owner adds it for the organisation.

How do I get into the Connectors Directory?

Submit the connector to Anthropic for review. Reviewers check who owns the API, how users authenticate, what data is handled, that each tool matches its description and carries the right read-only or destructive hint, and that a test account works. Interactive connectors also need screenshots.

Connectors vs skills vs desktop extensions

A connector gives Claude access to a product. A skill (a SKILL.md folder) teaches Claude how to do a task. A desktop extension (.mcpb) packages a local MCP server for one-click install in Claude Desktop. For a product with user accounts, a remote connector is the path.

What are interactive connectors (MCP Apps)?

Since January 2026, connectors can show interactive UI inside Claude, such as a board, a chart or a draft, using the MCP Apps extension that ChatGPT also supports.

Which products benefit most?

B2B tools where people already ask Claude for help: CRMs, project tools, analytics, design and support. The connector turns a question into your product’s answer, with that user’s permissions.

FAQ

Claude questions,
answered.

How do I build a Claude connector?

Build a remote MCP server with your tools and sign-in, then add it in Claude as a custom connector. With Flow you write the tools and Flow serves the server with each user’s sign-in.

How do I add a custom connector to Claude?

Settings → Connectors → add custom connector, then paste the server URL. Available on paid plans; on Team and Enterprise an owner adds it.

How do I get listed in the Connectors Directory?

Submit the connector to Anthropic with a working test account, tool descriptions with read-only or destructive hints, and screenshots for interactive connectors.

What is the difference between a connector and a skill?

A connector gives Claude access to a product through MCP. A skill is a set of instructions and files that teaches Claude how to do a task.

Local or remote MCP server?

Remote, for a product with users: it works across Claude’s apps and is the path to the directory. Local servers suit tools on one machine.

Does the same connector work in ChatGPT?

Yes, both use MCP. A Flow project ships to Claude, ChatGPT and a CLI from the same tools.

What OAuth does Claude need?

MCP’s authorization spec, based on OAuth 2.1. Flow handles it, so each user signs in to their own account.

Put your product inside Claude.

One open-source TypeScript project. The same agent on WhatsApp, iMessage, Telegram, ChatGPT and more.

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