Use Thirdfy in ChatGPT
Connect Thirdfy to ChatGPT as a custom MCP server, sign in with your Thirdfy account, and ask your agent to read markets, check venues and preview trades in plain words.
Talk to ChatGPT, and your agent reads markets and trades for you. Add Thirdfy to ChatGPT once and sign in with your Thirdfy account. Then ask in plain words: check your venues, find trending tokens, get a quote, or preview a swap. ChatGPT shows you each trade first and runs it only when you confirm.
What you need
- A ChatGPT plan that lets you add a custom MCP server. This depends on your plan and, in a work or school workspace, on your admin. Some plans need developer mode turned on first. Follow OpenAI's current help to check yours.
- A Thirdfy account. You can create it while you connect.
- Funds in your agent's wallet, if you want to trade. You can read and preview without them.
1. Add Thirdfy to ChatGPT
- Open ChatGPT Plugins.
- Click the + button, then Add custom MCP server.
- Name it
Thirdfy. Add a short description, such as "Read markets and trade for my Thirdfy agent". - Under Connection, paste
https://mcp.thirdfy.com/mcpas the URL. - For authentication, choose OAuth. Thirdfy uses sign-in, not a pasted key.
- Read the risk warning and click I understand and want to continue.
- Click Create as a plugin. ChatGPT lists the Thirdfy tools it found.
If you can't find these options, your plan or workspace may not allow custom MCP servers yet, or OpenAI has moved them. Follow OpenAI's current help for where the setting lives.
2. Sign in and pick your agent
ChatGPT opens the Thirdfy sign-in page. Sign in with email, Google or a wallet, the same way you do on thirdfy.com. Then:
- Pick your agent, or click Create a new agent and give it a name. Each agent has its own wallet. ChatGPT acts for this one agent only.
- Tick Trade within your agent's limits if you want ChatGPT to place trades. Without it ChatGPT can only look, and it asks you to sign in again before its first trade.
- Keep Stay connected on if you don't want to sign in again for 30 days.
- Click Approve.
Read is always granted. It lets ChatGPT see actions, balances, positions and venue readiness.
3. Use Thirdfy in a chat
Start a new chat. Type @, pick Thirdfy, and ask in plain words. Starting your message with "Using Thirdfy" also helps ChatGPT pick the right tools.
Check your venues
ChatGPT tells you which venues your agent can use and, for each one, whether funding, credentials and approvals are in place. If a venue isn't ready, it says what's missing.
Find tokens
Get a quote
A quote reads the price only. Nothing is signed or sent.
Preview a trade
ChatGPT previews the trade with Thirdfy. It shows the trade, its value, your limits and whether Thirdfy would run it. If something is missing, such as funds or gas, the preview says so before anything moves.
Preview, then confirm
In ChatGPT, a preview appears as an order card. When the trade is within your limits, the card shows Place order.
- Click Place order.
- The card asks you to confirm the exact trade within 5 minutes.
- Click Confirm order to send it, or Cancel to stop. If you cancel, nothing is sent.
When ChatGPT runs a trade without a card, Thirdfy still pauses and asks you to confirm first. ChatGPT shows you a confirmation form, or a summary of the trade and a question. Nothing runs until you say yes.
ChatGPT never places a trade on its own.
What happens before every trade
- You see it first. ChatGPT shows the trade and asks you to confirm before it runs.
- Your agent's limits apply. Per-trade and daily limits, and the actions you allow, are checked on every trade. Anything outside them is refused.
- Venues are checked. Thirdfy refuses a venue order when the venue isn't ready, and says why.
To see or end ChatGPT's access, open auth.thirdfy.com/connections and click Revoke.
If something goes wrong
| What you see | What to do |
|---|---|
| You can't find Add custom MCP server | Your plan or workspace may not allow it, or developer mode is off. Check OpenAI's current help, or ask your workspace admin |
| ChatGPT asks you to sign in again before a trade | You granted Read only. Sign in again and tick Trade |
A trade fails with insufficient_scope | Same cause. Reconnect and tick Trade |
| A venue isn't ready | Ask ChatGPT what's missing. Fund the agent's wallet or finish venue setup in Thirdfy |
| An action is not allowed for this agent | Your agent has an action allowlist without that action. Allow it for the agent, or pick another agent |
| ChatGPT doesn't use Thirdfy | Start a new chat, type @ and pick Thirdfy, and start your message with "Using Thirdfy" |
| ChatGPT says it's not connected | Open the Thirdfy connection on the Plugins page and sign in again |
For developers
| MCP URL | https://mcp.thirdfy.com/mcp (streamable HTTP, OAuth sign-in) |
| No account | https://mcp.thirdfy.com/mcp/public with no authentication: catalog, signals, help, and email or wallet onboarding |
| Sign-in | auth.thirdfy.com. Scopes: mcp:read (always), mcp:trade, offline_access (up to 30 days) |
| Tools | 17 for a signed-in app, including previewOrder, walletExecute, getVenueReadiness and getProviderActions |
| Confirmation | A form, or CONFIRMATION_REQUIRED with a confirmationToken valid for 5 minutes |
A signed-in app can't use agentRun, executeIntent, onboarding or delegation tools. For those, and for your own app on OpenAI models, use an agent key (Authorization: Bearer agent-...) with the Responses API or Codex. Get a key with email onboarding (startEmailOnboarding, then completeEmailOnboarding) or with the CLI:
See OpenAI for the Responses API and Codex setup.