Customer.io MCP

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API KEY

MARKETING AUTOMATION

Every campaign, customer segment, and transactional message your team sends lives in Customer.io. Customer.io MCP gives your agent authenticated access to campaigns scoped to the user who authorized it.

  • Acts as the user: Access and write actions stay tied to the Customer.io MCP account that authorized the agent.
  • Credentials stay vaulted: AES-256, resolved at request time, never in LLM context.
  • Scoped before every call: User permissions enforced. 90-day audit trail.
Customer.io MCP
agent · Acme Q3
Run
Which triggered campaigns sent this week had open rates below 20%?
S
customerio_campaigns_list
78ms
Marketing automation agent
3 campaigns underperformed. welcome_sequence (12.4%, 9,800 sent), trial_day7 (17.8%, 4,200 sent), churn_win_back (14.2%, 2,100 sent).
Sources: 3 campaigns, triggered email, Oct 28 to Nov 1
customeriomcpmcp
3 campaigns
18:29
Message Claude...

Tools your marketing automation agent reaches for on Customer.io MCP, scoped per user.

CALL ANY TOOL
List and inspect campaigns, track events, query customer profiles, and send transactional messages.
customerio_campaigns_list
List campaigns
List all Customer.io campaigns with status, type, and send count.
Parameters
Name
Type
Required
Description
type
string
Optional
Campaign type: email, push, sms, webhook
limit
integer
Optional
Max campaigns to return
customerio_campaign_get
Get campaign
customerio_customers_search
Search customers
customerio_customer_get
Get customer
customerio_event_track
Track event
customerio_transactional_send
Send transactional
Build your Agent
Drop the toolkit in, point it at the user, and your marketing automation agent can use Customer.io MCP from the first run.
import { ScalekitClient } from "@scalekit-sdk/node";
import { DynamicStructuredTool } from "@langchain/core/tools";
import { createReactAgent } from "@langchain/langgraph/prebuilt";
import { z } from "zod";

const sk = new ScalekitClient(envUrl, clientId, clientSecret);

const { tools } = await sk.tools.listScopedTools("user_123", {
filter: { connectionNames: ["customeriomcp"], toolNames: ["customerio_campaigns_list", "customerio_campaign_get", "customerio_customers_search"] },
pageSize: 100,
});

const lcTools = tools.map((t) => new DynamicStructuredTool({
name: t.tool.definition.name,
description: t.tool.definition.description,
schema: z.object({}).passthrough(),
func: async (args) => {
const { data } = await sk.tools.executeTool({
toolName: t.tool.definition.name,
identifier: "user_123",
params: args,
});
return JSON.stringify(data);
},
}));

const agent = createReactAgent({ llm, tools: lcTools });
import { ScalekitClient } from "@scalekit-sdk/node";
import OpenAI from "openai";

const sk = new ScalekitClient(envUrl, clientId, clientSecret);
const openai = new OpenAI();

const { tools } = await sk.tools.listScopedTools("user_123", {
filter: { connectionNames: ["customeriomcp"], toolNames: ["customerio_campaigns_list", "customerio_campaign_get", "customerio_customers_search"] },
pageSize: 100,
});

const llmTools = tools.map((t) => ({
type: "function",
function: {
name: t.tool.definition.name,
description: t.tool.definition.description,
parameters: t.tool.definition.input_schema,
},
}));

const resp = await openai.responses.create({
model: "gpt-4o", input: prompt, tools: llmTools,
});
import { ScalekitClient } from "@scalekit-sdk/node";
import Anthropic from "@anthropic-ai/sdk";

const sk = new ScalekitClient(envUrl, clientId, clientSecret);
const anthropic = new Anthropic();

const { tools } = await sk.tools.listScopedTools("user_123", {
filter: { connectionNames: ["customeriomcp"], toolNames: ["customerio_campaigns_list", "customerio_campaign_get", "customerio_customers_search"] },
pageSize: 100,
});

const llmTools = tools.map((t) => ({
name: t.tool.definition.name,
description: t.tool.definition.description,
input_schema: t.tool.definition.input_schema,
}));

const msg = await anthropic.messages.create({
model: "claude-sonnet-4-6", max_tokens: 1024,
tools: llmTools,
messages: [{ role: "user", content: prompt }],
});
import { Agent } from "@google/adk/agents";
import {
MCPToolset, StreamableHTTPConnectionParams,
} from "@google/adk/tools/mcp";

const toolset = new MCPToolset({
connectionParams: new StreamableHTTPConnectionParams({
url: "https://mcp.scalekit.com/customeriomcp",
headers: { Authorization: `Bearer ${userScopedToken}` },
}),
});

const agent = new Agent({
name: "agent", model: "gemini-2.0-flash",
tools: await toolset.getTools(),
});
Try these prompts
Paste any prompt into your agent to start using Customer.io MCP.
Search & recall
Copy the prompt
Copied
List all active email campaigns.
Copy the prompt
Copied
Which campaigns are in draft status?
Copy the prompt
Copied
Find customers in segment [segment name].
Copy the prompt
Copied
Get metrics for campaign [campaign name].
Action & sends
Copy the prompt
Copied
Track event [event name] for customer [id].
Copy the prompt
Copied
Send transactional [template id] to [email].
Copy the prompt
Copied
List all customers with attribute [attr] = [value].
Copy the prompt
Copied
Pull open and click rates for [campaign].
Reporting & optimization
Copy the prompt
Copied
Which campaigns had the lowest open rates this week?
Copy the prompt
Copied
Compare send volume by channel this month.
Copy the prompt
Copied
List customers who triggered [event] but did not convert.
Copy the prompt
Copied
Show unsubscribe rate by campaign type.
SEE HOW AUTH WORKS
Users authorize Customer.io MCP once. Their credentials stay vaulted, every call is checked, and every action is logged.
1
Authorize
Your user connects
Customer.io MCP
once. We tie it to their identity and the meetings they approved — no shared bot account, no org-wide access
Who:
user ‘A’
when:
Once per user
access:
Limited to user
2
Store
Their
Customer.io MCP
token lives in a vault scoped to them. User A's meetings are never reachable by an agent acting for user B, even on the same connection
vault:
encrypted
scope:
per-user
tokens:
auto-refreshed
3
Resolve
When your agent calls a
Customer.io MCP
tool, we fetch the right token server-side. It never touches your agent, never appears in the LLM context, never shows up in your logs
speed:
~40ms
check:
before every call
seen by:
nobody
4
Audit
Every
Customer.io MCP
tool call is logged — who triggered it, which meeting was fetched, what came back. 90 days of history, tied to the user who authorized it
history:
90 days
export:
SIEM-ready
logged:
every call
Test other agents
Same per-user auth pattern across other marketing automation agents and MCP connectors. Working code, live demos, fork what fits.
SALES
Outbound prospecting agent
Build targeted prospect lists with Apollo, enrich with firmographic data, and draft personalised outreach. Runs on a schedule.
GTM
HubSpot to Slack updates agent
Watch HubSpot deal stage changes and post structured updates to the right Slack channel. Reps stop checking the CRM all day.
Why Scalekit
Secure your agent's access. Connectors ship in minutes
Other connector libraries treat auth as a demo afterthought. Scalekit starts with user identity, scope enforcement, and audit.
01.
Campaigns sent from the wrong sender identity
A shared Customer.io API key looks fine in a demo. In production, every transactional send and event track appears as a service account. Attribution breaks. Scalekit resolves the actual user's key so sends come from the right identity.
// shared API key
key = "api_customerio_shared_xxx"
audit → bot_service_account
user_filter → broken

// scalekit · per-user
key = resolve(user_id)
audit → user_abc
scope → enforced ✓
02.
Authentication is not authorization
03.
Multi-tenancy is architectural
04.
Customer.io MCP today. Others tomorrow.
“Our agents act across Salesforce, Gong, Google Drive, and more, on behalf of every customer. Scalekit behind the scenes meant we can keep adding tools without ever rebuilding how credentials or tool calling work.”
Venu Madhav Kattagoni
Head of Engineering / Von
Frequently Asked Questions
Does the agent access Customer.io MCP as the user or as a shared key?
As the user. Each workspace member authorizes once and Scalekit resolves their credential at request time. Audit logs attribute every action to that user, not a shared service account.
Where is the Customer.io MCP api key stored?
Can I limit what the agent is allowed to do in Customer.io MCP?
What happens when a user revokes Customer.io MCP access?
Can the agent send messages to any customer in the workspace?
Start in your coding agent
Up and running in one command
Install the Scalekit skill in your editor of choice. Connector, auth, tools, prompt, all wired up
Claude Code REPL
/plugin marketplace add scalekit-inc/claude-code-authstack
/plugin install agentkit@scalekit-auth-stack
Cursor Code REPL
# ~/.cursor/mcp.json
{
""mcpServers"": {
""customeriomcp"": {
""url"": ""https://mcp.scalekit.com/customeriomcp"",
""headers"": { ""Authorization"": ""Bearer $SCALEKIT_TOKEN"" }
}
}
}
Codex Code REPL
# ~/.codex/config.toml
[mcp_servers.customeriomcp]
url = ""https://mcp.scalekit.com/customeriomcp""
auth_env = ""SCALEKIT_TOKEN""
Copilot Code REPL
# .vscode/mcp.json
{
""servers"": {
""customeriomcp"": {
""url"": ""https://mcp.scalekit.com/customeriomcp"",
""type"": ""http""
}
}
}