MCP client guides
Connect Thirdfy MCP in Claude, Claude Code, Cursor, OpenAI, Grok and OpenClaw. Sign in with your Thirdfy account, or onboard by email and add your agent key.
Connect Thirdfy to the app or platform your agent runs in. In a chat app (Claude, ChatGPT, Cursor, Claude Code), you sign in with your Thirdfy account. Hosted agents and APIs use an agent key, which you get in four steps below.
Step-by-step walkthroughs with screenshots are in Guides.
Pick a host
Sign in with Thirdfy
If your host supports MCP sign-in (claude.ai, Claude Desktop, Claude Code, ChatGPT, Cursor), skip the steps below:
- Add
https://mcp.thirdfy.com/mcp. - Sign in with your Thirdfy account.
- Pick an agent or click + Create a new agent, then choose Read or Trade.
See Connect.
The four steps (agent key)
1. Connect without a key
Add https://mcp.thirdfy.com/mcp/public to your host. You need no key and no account. This connection can call these tools:
| Tool | Use |
|---|---|
getThirdfyHelp | Guidance on onboarding, auth, wallets and frameworks |
getActionsCatalog, getProviderActions | Every action, or one provider's actions |
getChainCapabilities, getNonEvmCapabilities | Supported chains |
describeOnboardingPath | The setup steps for your situation |
startEmailOnboarding, completeEmailOnboarding | Create your account, agent key and execution wallets |
startWalletOnboarding, completeWalletOnboarding | The same with an agent's own EVM key instead of email |
Signal reads (get_cmc_*, get_openmarket_*, …) | Public market data |
2. Onboard by email
Ask your agent:
The agent calls startEmailOnboarding, and Thirdfy emails you a code. Give the code to the agent. It then calls completeEmailOnboarding with acceptTerms: true.
On first sign-up the response includes your agent API key (agent-...) at data.bootstrap.agentApiKey, together with your execution wallets. Save the key now in a password manager or secret store. It is shown once.
Already set up with the Agent CLI? The CLI keeps the same key in ~/.thirdfy/config.json.
3. Add the key to the connector
Thirdfy MCP doesn't remember you between calls. So every call that acts for your agent must carry the key in the connection header:
X-API-KEY: agent-... works too.
- Switch the connector URL to
https://mcp.thirdfy.com/mcp. - Add the header in your host's connector settings. Each guide shows where.
- Reconnect.
Without a key or a sign-in, plain /mcp asks you to sign in.
Putting the key inside tool arguments is not enough. Without the header, any tool beyond the list in step 1 returns 401 Authentication required. With the header, Thirdfy fills in your key on every call. If the agent passes a different key in the arguments, the call fails with AGENT_IDENTITY_MISMATCH.
4. Read, then act
Before a trade, deposit or order, check the venue and finish any setup it lists:
agentKey is your agent's 0x identity address, from onboarding or thirdfy-agent whoami. It is not the execution wallet.
agentRun and walletExecute refuse a write when funding, credentials, approvals, policy or credits are not ready.
Shared endpoint
| Item | Value |
|---|---|
| MCP (streamable HTTP) | https://mcp.thirdfy.com/mcp (agent key, or sign in) |
| Public, no account | https://mcp.thirdfy.com/mcp/public |
| Typed tools | https://mcp.thirdfy.com/mcp?toolsets=signals (see Discovery) |
| REST per tool | POST https://mcp.thirdfy.com/tool/<toolName> |
| Tool manifest | GET https://mcp.thirdfy.com/tools |