Sell from your AI assistant
Connect your own AI assistant to your Commonplace account, then list, price and manage what you sell by chatting with it. Any assistant or app that can add an MCP connector and sign in works, whichever one you already use. Below are the steps for ChatGPT, Claude and Claude Code, and what to enter in anything else.
https://trycommonplace.com/mcpHow to connect
The same four moves in every assistant. Exact menus for ChatGPT, Claude and Claude Code are below.
What it can do
- Work out the right category for your item and the details it needs before it can be listed.
- Show what similar items list for, and what buyers would pay for the take-home you want.
- Create a listing from your description and photos. You see a preview first, with the title buyers will see, the price they will pay and what you take home.
- Save a draft when you have no photos yet, with a link to add photos and publish it, and discard drafts you no longer want.
- Edit your listings: the title, what you take home, the least you would take home, category, condition, pickup city and photos.
- Put an inactive listing back on sale, or take a listing down.
- Show your listings and drafts, accept, counter or decline offers, and show your sales with the payout on each.
- Search live listings, quote delivery to a ZIP code, answer questions about how Commonplace works, and pass a request to our support team.
What it cannot do
- Take or send payments, or see or change how you are paid.
- See your password or sign-in codes, or change your phone number, email or address.
- Delete your account.
- Edit a listing's description, change a listing that is reserved or sold, or take down a listing with an active order. Our support team can help with those.
- Change anything without you. Every change is shown as a preview first and happens only after you confirm it.
Connect Claude
This works on claude.ai and in the Claude desktop app. Custom connectors are available on every Claude plan; the Free plan allows one.
- 1In Claude, open Customize, then Connectors.
- 2Choose +, then Add custom connector.
- 3Enter a name, such as Commonplace, and https://trycommonplace.com/mcp as the URL. Leave the advanced settings empty, and choose Add.
- 4When the Commonplace page opens, sign in to your Commonplace account and allow access.
- 5In a chat, turn Commonplace on from the + button, under Connectors.
On a Team or Enterprise plan, an Owner adds the connector under Organization settings, then Connectors. Members then find it under Customize, then Connectors, and choose Connect.
Connect Claude Code
- 1In a terminal, run: claude mcp add --transport http commonplace https://trycommonplace.com/mcp
- 2Start Claude Code, run /mcp, and follow the steps to sign in to your Commonplace account in your browser.
- 3On the consent screen, tick the box to allow changes if you want Claude Code to create and edit listings (see below).
Add --scope user to the first command to use Commonplace in all your projects, not only the current one. To remove it, run claude mcp remove commonplace.
Connect ChatGPT
You add Commonplace to ChatGPT yourself, with developer mode. OpenAI offers developer mode on the ChatGPT website for Plus, Pro, Business, Enterprise and Education accounts. In a Business, Enterprise or Education workspace, an admin controls developer mode and may need to add the connector for you.
- 1On chatgpt.com, open Settings, then Security and login, and turn on Developer mode.
- 2Go to chatgpt.com/plugins and choose the + button.
- 3Enter a name, such as Commonplace, and https://trycommonplace.com/mcp as the server address. If ChatGPT asks how to authenticate, choose OAuth. Then create it.
- 4When the Commonplace page opens, sign in to your Commonplace account and allow access.
- 5Start a new chat and add Commonplace from the + menu.
ChatGPT asks you to confirm before it runs a tool that makes a change, as well as the preview Commonplace shows. ChatGPT's menus change from time to time; OpenAI's help article "Developer mode and MCP apps in ChatGPT" has its current steps.
Any other assistant
Nothing here is particular to the assistants named above. Anything that can add a remote MCP server and sign in with OAuth connects the same way, including editors and desktop tools. Give it:
- Server address: https://trycommonplace.com/mcp
- Transport: Streamable HTTP
- Sign-in: OAuth with PKCE. The app registers itself, so there is no client ID or secret to enter.
The consent screen
When you connect, Commonplace shows which app is asking, which account it will use, what it will be able to do and what it will never be able to do.
- Claude and ChatGPT, added as above: choose Allow. The app can then look things up and, each time you confirm, make changes.
- Apps Commonplace has not verified, such as Claude Code, Cursor and other desktop apps: the screen says the app is not verified, because an app chooses its own name. Allow read only connects it without the ability to change anything. To let it create and edit listings and answer offers, tick Allow [app name] to make these changes on my account, then choose Allow, including changes. The box starts unticked every time you connect.
Connected read only, an app can still search, check prices, show your listings, offers and sales, and pass a request to our support team.
Photos
- Attach photos in the chat, or give your assistant links to them. A link has to be an https address that opens the photo itself.
- Photos can be JPEG, PNG, WebP or GIF. Photos in an iPhone's HEIC format cannot be read: save them as JPEG first, or add them on the listing's edit page.
- A linked photo can be up to 15MB. Large photos are resized, and location data is removed from every photo.
- Up to 8 new photos can be added at a time, and a listing holds up to 24.
- A photo an assistant writes into its request, rather than attaching or linking it, only works when it is small: the whole request is limited to 256KB.
- If your assistant cannot pass photos on, it can save the listing as a draft and give you a link to add photos and publish it on Commonplace.
An item you listed somewhere else
Commonplace does not import listings from other websites, and the connector does not open pages such as a Facebook Marketplace, Craigslist or OfferUp listing. Paste the description into your chat and attach your photos, and your assistant can create the Commonplace listing from those.
Good to know
- Listing is free, and creating a listing never adds paid promotion.
- A listing with at least one photo publishes straight away. An item outside our usual categories is reviewed first.
- Shortly after a listing publishes, Commonplace writes its description from your details, and this can adjust the title. Check it on the listing page, and contact support if anything needs correcting.
- Accepting an offer sets the listing's price to the offer amount, and a counter offer becomes the listing's price for every buyer.
Disconnect
Open My account, then Settings, and under Connected apps choose Disconnect next to the app. It loses access at once. Removing Commonplace from your assistant does not always end its access, so disconnect it here too.
Your data
A connected app sees only what you allow when you connect it: the catalogue, your name with a masked phone and email, your own listings with their offers and sales, and your full email address if the app asks for it. We keep a record of each request an app makes so we can run and secure the service. The Privacy Policy at https://trycommonplace.com/privacy explains what we collect and how long we keep it.
Help
Answers to common questions are at https://trycommonplace.com/faq, or call us on (516) 357-5989.