Owner’s Desk
Our own OAuth 2.1 connector. It reaches the owner’s Stripe and Google accounts, every write waits for a confirm token, and every action lands in an audit log.
Connector builds / A ChatGPT app for your SaaS
Put your SaaS inside ChatGPT.
A ChatGPT app for your SaaS is an MCP server that OpenAI reviews and lists. OpenAI’s developer docs now call the listing a plugin, published in one directory shared by ChatGPT and Codex, and it can carry an MCP server, skills and optional UI. To pass review you need OAuth (the submission portal has no API-key flow), tool annotations, four public URLs including a privacy policy and terms, a test account that works without MFA, five positive and three negative test cases, and a video walkthrough. I build the server and prepare every one of those.
Nine of our tools are listed in Anthropic’s Claude directory.
At a glance
- Built on
- An MCP server, the same protocol Claude uses
- Listed as
- A plugin in the directory shared by ChatGPT and Codex
- Auth
- OAuth: the portal has no API-key or bearer-token input
- Review asks for
- Five positive and three negative test cases, plus a video
Checked October 12, 2026
App, plugin, connector
Three names for one server.
Buyers search for a ChatGPT app. OpenAI’s current developer docs say plugin. Anthropic says connector. Under all three sits the same thing: a remote MCP server that exposes your product’s actions as tools. Build that server well once, and the ChatGPT listing and the Claude listing are two submissions of it, not two projects.
What differs is the paperwork. OpenAI asks for things Anthropic does not, and the reverse, so I prepare each submission against its own published rules.
What OpenAI’s review asks for
The ChatGPT submission, item by item.
Read from OpenAI’s plugin submission and review pages on the date at the foot of this page:
- Organization owners can submit; other members need the Apps Management Write permission, and publishing under your company’s name requires verification
- Domain verification: you host the exact challenge token from the portal as plain text at the URL it shows
- Only one MCP server can be connected per plugin
- OAuth for anything protected: the portal provides no API-key connection flow and no bearer-token input
- Four listing URLs for public review: website, support, privacy policy and terms of service
- A dedicated test account that works immediately, with no MFA
- Exactly five positive and three negative test cases on the first review, plus a video walkthrough reviewers can open
- Tool annotations: readOnlyHint, destructiveHint and openWorldHint, set to match what each tool really does
Where the value is
Your customers stop switching tabs.
When a small business owner asks ChatGPT to draft an email or plan the week, the answer comes from general knowledge. With your product connected, the same conversation can read their real data from your system and, with their yes, write back to it. The question “what is on my plate today” gets answered from your product instead of from a guess.
That is also why the approval step matters. Every write I build drafts first, shows the customer exactly what will change, and runs only after they confirm. Owner’s Desk, our own connector, works this way: a drafted invoice returns a one-time confirm token, and nothing is sent until the owner says yes.
- Listed in Anthropic’s Claude directory
- 9
- In review with Anthropic
- 4
- In the official MCP Registry
- 15
- Tools Claude can call
- 69
What we have shipped
Built and running, not a deck.
AI Front Door
One multi-tenant deploy that gives every business its own connector, white label, under an agency’s brand.
Small Business Agent Bench
Our open benchmark of how well AI agents handle real small-business work: 200 tasks, sandboxed tools, deterministic grading.
The package that fits
Connector Build
Connector Build ships the server and both submissions, ChatGPT and Anthropic’s Claude directory, so you are not paying twice for one protocol.
Your customers do their real work in your product from inside the assistant they already use. Set scope, set price, quoted in the conversation, and changes to what we built are included.
Straight answers
What teams ask next.
Is a ChatGPT app the same as a ChatGPT plugin?
In OpenAI’s current developer docs, the listing you submit is called a plugin, and it can include an MCP server, skills and optional UI. People still search for “ChatGPT app”. The thing I build for you is the MCP server underneath either name.
Can we use our existing API keys for sign-in?
Not in the submission portal: OpenAI says it provides no API-key connection flow and no bearer-token input. I add an OAuth layer in front of your API so each customer signs in with their own account.
Does the ChatGPT app need a custom UI?
No. UI is optional and returned from selected MCP tools. Most first versions are tools only, and UI comes later where a table or a card genuinely helps.
Who decides whether it gets listed?
OpenAI does. I build to every published rule and file the submission. Feedback comes by email, and once a plugin is approved you choose when to publish.
Sources
I wrote this page for Modern Mustard Seed, and we sell the service it describes. Every fact about Anthropic, OpenAI or another company was read from the page linked here on October 12, 2026.
One next step
Send me your API docs.
Tell me your product and where your API reference lives. I will come back with the jobs your customers would do in Claude and ChatGPT, the tools I would build, and the package that fits. Managed for you, end to end, and the code is yours.
Claude is a product of Anthropic, and ChatGPT is a product of OpenAI. Modern Mustard Seed is an independent studio and is not affiliated with or endorsed by either.