This page is part of the Customer.io documentation. For the complete documentation index, see llms.txt.

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Update your MCP client

When we add, rename, or change MCP tools, you might need to update hardcoded tool references or reconnect your client.

Update hardcoded tool references

If you’ve hardcoded references to specific v1 tool names—like create_segment, get_profile, or list_segments—in skills, workflows, etc, you’ll need to update them. In most cases, we recommend that you use natural language prompts like “list my campaigns”.

Check your workflows, scripts, and prompts for hardcoded tool names:

• Custom GPT instructions that name specific tools (for example, “use the create_segment tool”)
• Claude Projects with tool references in the system prompt
• Saved prompts or workflows that call out specific tools by name
• Scripts that call the MCP server directly with a specific tool shape

Reconnect your client

If your client struggles to pick up the new tools, you may need to reconnect.

1. Remove the Customer.io connection from your client (Claude Desktop, ChatGPT, Cursor, or wherever you’ve configured it).
2. Re-add the connection following our setup instructions for ChatGPT, Claude, or Cursor and other IDEs.
3. Verify the new tools are available—ask your AI tool to list the available Customer.io tools, or try a prompt that depends on the new tool surface.

Your server URL and authentication don’t change. You just need a fresh connection so your client picks up the latest tool list.

May 2026 changes: cio_api split into verb-specific tools

We replaced the single cio_api tool with three verb-specific tools:

This lets MCP clients that support tool-level permissions (like Claude’s Connectors UI) separate reads from writes and deletes. If your client supports this, you can allow cio_read_api automatically while requiring approval for cio_write_api and cio_delete_api.

What changed:

• The method parameter is gone from cio_read_api (it’s always GET) and cio_delete_api (it’s always DELETE). cio_write_api still accepts method (POST, PUT, or PATCH—defaults to POST).
• The read_only parameter is gone. The verb constraint is now built into each tool.
• The body parameter is only available on cio_write_api.
• The page_all parameter is only available on cio_read_api.

If you have hardcoded references to cio_api in custom GPT instructions, Claude Projects, or scripts, update them to the appropriate verb-specific tool.

Early May 2026 changes: expanded capabilities, tools replaced with cio_*

We replaced the v1 tool architecture (purpose-built tools like create_segment and get_campaign) with a smaller set of generic, schema-aware cio_* tools that cover the full Journeys UI API and CDP Data Pipelines API surface. Your existing sessions and natural language prompts continue to work—you don’t need to do anything if you interact with the MCP server through normal conversation.

The current version supports write operations the v1 set didn’t:

• Create, edit, and launch campaigns—build and manage automated workflows from your AI tool.
• Send newsletters—draft and send one-time messages to your audience.
• Manage segments—create, update, and delete segments.
• Work with transactional messages—manage your transactional email and push content.
• Access customer profiles—look up and manage people in your workspace.