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The Terrapin API is available as a Model Context Protocol (MCP) server. Once connected, Claude or ChatGPT can call every API endpoint as a tool (bond search, pricing, documents, and more) without you writing any integration code. Every MCP request uses the same API key as a direct HTTP call. Requests count against your rate limits and quotas the same way. MCP server URL: https://terrapinfinance.com/mcp

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Claude

1

Open Connectors

In claude.ai, click Customize in the top-right corner of the chat window, then click Connectors.
2

Add a custom connector

Click the + button and select Add custom connector.
3

Fill in the connector details

  • Name: Terrapin
  • URL: https://terrapinfinance.com/mcp
4

Add your API key

Expand Advanced settings and paste your Terrapin API key into the OAuth Client Secret field. The OAuth Client ID field accepts any non-empty string.
5

Save

Click Add. The Terrapin connector appears under your web connectors and can be toggled on per conversation.
6

Allow terrapinfinance.com (sandboxed environments only)

If Claude runs in a container or an agent sandbox with a domain allowlist, add terrapinfinance.com as described in Network access. Skip this on an ordinary network.
Claude’s custom connector UI requires OAuth credentials even though Terrapin authenticates with a bearer token. We map the OAuth client credentials flow onto your existing API key: the client secret you paste is used directly as the bearer token on every MCP request.

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ChatGPT

ChatGPT connects to remote MCP servers as custom connectors (also called Plugins). You need Developer Mode enabled, which is available on Plus, Business, Enterprise, and Edu plans.
1

Add a plugin

In ChatGPT, open Settings → Plugins → Add → Add custom MCP server
2

Fill in the plugin details

  • Name: Terrapin
  • Connection URL: https://terrapinfinance.com/mcp
3

Add your API key

Expand Advanced OAuth settings and paste your Terrapin API key into the OAuth Client Secret field. The OAuth Client ID field accepts any non-empty string, for example Terrapin.
4

Sign in and verify

Click Create as plugin. When ChatGPT redirects you to authorize the connection, sign in to your Terrapin account. ChatGPT then calls tools/list and shows the available Terrapin tools. Enable the plugin in a new chat via the tool picker.
Running in a container, an agent sandbox, or behind a corporate proxy? See Network access for the host to allow, or the assistant will find documents it cannot open.

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Example prompts

Once connected, you can ask things like:
  • “Search for general obligation bonds from California issued after 2020”
  • “Get the latest pricing for CUSIP 912810TM0”
  • “Retrieve the official statement for ISIN US3733832070”
The assistant calls the matching Terrapin API endpoints and returns the results in the conversation.