Customer.io MCP by usefulapi

Server Details

Query people, segments, campaigns, and message deliveries; send transactional email or broadcasts.

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Status: Healthy
Uptime: 69.6% over 54 days
Last Tested: 2026-10-10 15:12
Transport: Streamable HTTP · MCP 2025-06-18
URL
Repository: m190/usefulapi-mcp
GitHub Stars: 0

TDQS

A4/5.0

Scored 2026-08-31 02:45 across 13 tools

Disambiguation5/5

Each tool maps to a distinct resource and action: campaign, customer, segment, message, collection, export, or send. The potentially similar pairs like list_messages/get_customer_messages and list_segments/get_customer_segments are clearly differentiated by workspace-wide vs per-customer scope.

Naming Consistency5/5

All tools consistently use a customerio_ prefix with verb_noun snake_case naming. get_ is used for single-resource operations, list_ for collections, and send_/trigger_ for actions, creating a predictable pattern.

Tool Count5/5

13 tools is well within the ideal range for an API integration and each tool represents a meaningful endpoint. There is no obvious redundancy or padding; campaigns, customers, messages, segments, collections, exports, and sends all have coverage.

Completeness3/5

The surface is solid for reading Customer.io data and triggering sends, but it lacks common lifecycle operations like creating/updating/deleting customers, tracking events, or listing transactional templates. These are notable gaps that can force agents to rely on out-of-band IDs for send workflows.

Available Tools

13 tools

customerio_get_campaignGet campaign

Read-only

Inspect

Get a single campaign by id. App API: GET /v1/campaigns/{campaign_id}.

ParametersJSON Schema

Name	Required	Description	Default
`campaign_id`	Yes	Campaign id.

customerio_get_campaign_metricsGet campaign metrics

Read-only

Inspect

Get delivery/engagement metrics for a campaign over time. App API: GET /v1/campaigns/{campaign_id}/metrics.

ParametersJSON Schema

Name	Required	Description
`type`	No	Metric type filter (e.g. email, push, sms).
`steps`	No	Number of periods to return.
`period`	No	Bucket size. Default days.
`campaign_id`	Yes	Campaign id.

customerio_get_customer_attributesGet customer attributes

Read-only

Inspect

Get a single person's attributes (profile fields). App API: GET /v1/customers/{customer_id}/attributes.

ParametersJSON Schema

Name	Required	Description	Default
`customer_id`	Yes	The person's id (or cio_id / email, per your identifier setup).

customerio_get_customer_messagesGet customer messages

Read-only

Inspect

List messages (deliveries) sent to a single person. App API: GET /v1/customers/{customer_id}/messages.

ParametersJSON Schema

Name	Required	Description
`limit`	No	Max messages to return.
`start`	No	Pagination cursor from a previous response's `next`.
`customer_id`	Yes	The person's id.

customerio_get_customer_segmentsGet customer segments

Read-only

Inspect

List the segments a single person belongs to. App API: GET /v1/customers/{customer_id}/segments.

ParametersJSON Schema

Name	Required	Description	Default
`customer_id`	Yes	The person's id.

customerio_list_campaignsList campaigns

Read-only

Inspect

List all campaigns in the workspace. App API: GET /v1/campaigns.

ParametersJSON Schema

Name	Required	Description	Default
No parameters

customerio_list_collectionsList collections

Read-only

Inspect

List reusable data collections in the workspace. App API: GET /v1/collections.

ParametersJSON Schema

Name	Required	Description	Default
No parameters

customerio_list_exportsList exports

Read-only

Inspect

List data exports in the workspace. App API: GET /v1/exports.

ParametersJSON Schema

Name	Required	Description	Default
No parameters

customerio_list_messagesList messages

Read-only

Inspect

List sent messages (deliveries) across the workspace, filterable by type/campaign/newsletter. App API: GET /v1/messages.

ParametersJSON Schema

Name	Required	Description
`type`	No	Message type filter, e.g. email \| push \| sms \| in_app \| webhook \| slack \| twilio.
`limit`	No	Max messages to return.
`start`	No	Pagination cursor from a previous response's `next`.
`drafts`	No	Include drafts.
`campaign_id`	No	Filter to a specific campaign.
`newsletter_id`	No	Filter to a specific newsletter.

customerio_list_segmentsList segments

Read-only

Inspect

List all segments in the workspace (id + name + type). App API: GET /v1/segments.

ParametersJSON Schema

Name	Required	Description	Default
No parameters

customerio_search_customersSearch customers

Read-only

Inspect

Search/list people by a Customer.io filter (segment or attribute conditions). e.g. filter={"segment":{"id":7}} or {"and":[...]}. App API: POST /v1/customers.

ParametersJSON Schema

Name	Required	Description
`limit`	No	Max people to return.
`start`	No	Pagination cursor from a previous response's `next`.
`filter`	Yes	Customer.io filter object, e.g. {"segment":{"id":7}} or {"and":[{"attribute":{"field":"email","operator":"exists"}}]}.

customerio_send_transactional_emailSend transactional email

Destructive

Inspect

⚠️ SENDS A REAL EMAIL. Send a transactional email using a transactional message template. Delivers immediately to the to recipient. App API: POST /v1/send/email.

ParametersJSON Schema

Name	Required	Description
`to`	Yes	Recipient email address.
`body`	No	Override the email body.
`from`	No	Override the sender address.
`subject`	No	Override the subject line.
`identifiers`	Yes	Person identifiers, e.g. {"id":"..."} or {"email":"..."}.
`message_data`	No	Template variables (liquid) to interpolate into the message.
`send_to_unsubscribed`	No	If true, send even to unsubscribed recipients.
`transactional_message_id`	Yes	The transactional message template id (or trigger name).
`disable_message_retention`	No	If true, don't retain the message body.

customerio_trigger_broadcastTrigger broadcast

Destructive

Inspect

⚠️ SENDS TO REAL RECIPIENTS. Trigger an API-triggered broadcast, delivering to the resolved recipient set. App API: POST /v1/send/broadcast (posts to /v1/campaigns/{broadcast_id}/triggers).

ParametersJSON Schema

Name	Required	Description
`data`	No	Liquid variables available to the broadcast templates.
`recipients`	No	Recipient filter object (overrides the broadcast's configured audience).
`broadcast_id`	Yes	The API-triggered broadcast id.
`id_ignore_missing`	No	Skip recipients missing an id instead of erroring.
`email_add_duplicates`	No	Allow duplicate email recipients.
`email_ignore_missing`	No	Skip recipients missing an email instead of erroring.

Tool Schema Changelog

Recent tool additions, removals, and schema changes observed during successful MCP inspections.

13 tool updatesOct 9, 2026

Changedcustomerio_get_campaign3 fields changed

changedInput schema / $schema

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

removedInput schema / properties / campaign_id / anyOf

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "number"
-  }
-]

addedInput schema / properties / campaign_id / type
```
Added value: +[
+  "string",
+  "number"
+]
```

Changedcustomerio_get_campaign_metrics3 fields changed

changedInput schema / $schema

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

removedInput schema / properties / campaign_id / anyOf

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "number"
-  }
-]

addedInput schema / properties / campaign_id / type
```
Added value: +[
+  "string",
+  "number"
+]
```

Changedcustomerio_get_customer_attributes1 field changed

changedInput schema / $schema

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

Changedcustomerio_get_customer_messages1 field changed

changedInput schema / $schema

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

Changedcustomerio_get_customer_segments1 field changed

changedInput schema / $schema

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

Changedcustomerio_list_campaigns1 field changed

changedInput schema / $schema

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

Changedcustomerio_list_collections1 field changed

changedInput schema / $schema

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

Changedcustomerio_list_exports1 field changed

changedInput schema / $schema

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

Changedcustomerio_list_messages5 fields changed

changedInput schema / $schema

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

removedInput schema / properties / campaign_id / anyOf

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "number"
-  }
-]

addedInput schema / properties / campaign_id / type
```
Added value: +[
+  "string",
+  "number"
+]
```

removedInput schema / properties / newsletter_id / anyOf

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "number"
-  }
-]

addedInput schema / properties / newsletter_id / type
```
Added value: +[
+  "string",
+  "number"
+]
```

Changedcustomerio_list_segments1 field changed

changedInput schema / $schema

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

Changedcustomerio_search_customers1 field changed

changedInput schema / $schema

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

Changedcustomerio_send_transactional_email3 fields changed

changedInput schema / $schema

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

removedInput schema / properties / transactional_message_id / anyOf

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "number"
-  }
-]

addedInput schema / properties / transactional_message_id / type
```
Added value: +[
+  "string",
+  "number"
+]
```

Changedcustomerio_trigger_broadcast3 fields changed

changedInput schema / $schema

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

removedInput schema / properties / broadcast_id / anyOf

Removed value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "number"
-  }
-]

addedInput schema / properties / broadcast_id / type
```
Added value: +[
+  "string",
+  "number"
+]
```

13 tool updatesJul 18, 2026
- First observedcustomerio_get_campaign
- First observedcustomerio_get_campaign_metrics
- First observedcustomerio_get_customer_attributes
- First observedcustomerio_get_customer_messages
- First observedcustomerio_get_customer_segments
- First observedcustomerio_list_campaigns
- First observedcustomerio_list_collections
- First observedcustomerio_list_exports
- First observedcustomerio_list_messages
- First observedcustomerio_list_segments
- First observedcustomerio_search_customers
- First observedcustomerio_send_transactional_email
- First observedcustomerio_trigger_broadcast

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