klaviyo-mcp-server-extended

A community fork of Klaviyo's official klaviyo-mcp-server (v0.4.1) adding missing campaign/template traversal tools plus universal content support that the official server does not expose.

This is an unofficial, unsupported patch. It layers the missing tools onto the official code without changing any existing behavior — everything that works in the official server continues to work identically here.

Why this exists

As of April 2026, the official Klaviyo MCP server (v0.4.1) does not expose tools to:

1. List email templates (only fetch by known ID)
2. Traverse from a campaign or campaign message to its associated template
3. Clone a campaign or a template

These gaps make it impossible to clone an email campaign end-to-end through the MCP server or safely manage Klaviyo's newer reusable universal content blocks, even though the underlying REST API fully supports all of these operations and the bundled klaviyo-api Python SDK already has the methods wired up. This fork simply exposes them.

Tools added

These tools are thin wrappers around methods that already exist in the official klaviyo-api SDK. They follow the same style conventions as the surrounding code (@mcp_tool, get_klaviyo_client(), clean_result()).

All other tools from the official server are preserved unchanged.

Universal content workflow

For Klaviyo's newer reusable template blocks:

1. discover blocks with klaviyo_get_universal_content_blocks
2. inspect a block with klaviyo_get_universal_content_block
3. create or update reusable blocks with the universal content write tools
4. embed the returned block ID into template HTML with:

<div data-klaviyo-universal-block="block_id">&nbsp;<div>

Warning: updating or deleting a universal content block affects every template that uses it.

Relationship helpers are also available:

• template -> universal content blocks
• campaign -> universal content blocks

Authentication

Identical to the official local server: private API key via the PRIVATE_API_KEY environment variable. This fork does not provide OAuth or any remote hosting — OAuth is Klaviyo's own gateway at https://mcp.klaviyo.com/mcp and is not part of the open-source package.

The private API key needs the same scopes as the official server. For the new tools specifically:

• templates:read — for get_email_templates, get_template_for_campaign_message, get_universal_content_blocks, get_universal_content_block, get_universal_content_block_html
• templates:write — for clone_email_template, create_universal_content_block, update_universal_content_block, delete_universal_content_block
• campaigns:read — for get_messages_for_campaign, get_template_id_for_campaign_message
• campaigns:write — for clone_campaign

The full recommended scope set from Klaviyo's docs already covers all of these.

Installation

From PyPI

After this package is published, install and run the fork with:

uvx --from klaviyo-mcp-server-extended klaviyo-mcp-server

Pin the release version for reproducible MCP client configs:

uvx --from klaviyo-mcp-server-extended==0.4.6 klaviyo-mcp-server

From a local wheel

Build the wheel first:

uv build

Then run the generated wheel from dist/:

uvx --from ./dist/klaviyo_mcp_server_extended-0.4.6-py3-none-any.whl klaviyo-mcp-server

MCP client config (Claude Desktop, Cursor, VS Code)

Replace the official uvx klaviyo-mcp-server@latest invocation with uvx --from klaviyo-mcp-server-extended==0.4.6 klaviyo-mcp-server. For example, in Claude Desktop:

{
  "mcpServers": {
    "klaviyo": {
      "command": "uvx",
      "args": [
        "--from",
        "klaviyo-mcp-server-extended==0.4.6",
        "klaviyo-mcp-server"
      ],
      "env": {
        "PRIVATE_API_KEY": "YOUR_API_KEY",
        "READ_ONLY": "false",
        "ALLOW_USER_GENERATED_CONTENT": "false"
      }
    }
  }
}

The entry point command (klaviyo-mcp-server) is unchanged, so no downstream agent code needs to change — only the --from package is new.

Verifying the fork loaded

After restarting your MCP client, your tool list should include the six new tools alongside the existing ones. In Claude Desktop, click Search and tools → klaviyo to confirm.

Upstream relationship

• Based on klaviyo-mcp-server==0.4.1 from PyPI (published 2026-03-05)
• Version 0.4.8, based on the upstream 0.4.1 base plus added campaign/template traversal, universal content, and forward relationship support
• No changes to existing tools, models, utilities, prompts, or scripts
• The added tools are the only diff

If Klaviyo eventually ships equivalent tools upstream, uninstall this fork and revert to the official klaviyo-mcp-server@latest.

License

MIT, matching the upstream package. See LICENSE.