Skip to main content
Glama
thenavidm

Kit MCP Server

by thenavidm
OverviewSchemaSourceRelated ServersDiscussionsAdmin
TypeScript
Local

Update a subscriber

update_subscriber
Destructive

Modify a Kit subscriber's details, custom fields, or audience status. Requires confirm=true because changes may affect delivery or published data.

Instructions

Update a subscriber. May affect delivery, audience membership, published data or irreversible state. Requires confirm=true.

Input Schema

NameRequiredDescriptionDefault
fieldsNo
accountNoNamed private account from KIT_ACCOUNTS. Defaults to KIT_DEFAULT_ACCOUNT or the first configured account.
confirmNoSet true only when the user asked for exactly this action.
payloadNoComplete JSON body instead of individual body flags. Supports nullable fields and nested bulk structures. Cannot be combined with body flags or payload_file.
first_nameNo
payload_fileNoLocal JSON request body file, at most 5 MB. Contents are validated before the API call and are never logged.
email_addressNo
subscriber_idYesPositive subscriber id.

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed10 schema fields changedv3.0.0
    • addedInput schema / $defs
      Added value: +{
+  "fields": {
+    "additionalProperties": {
+      "type": "string"
+    },
+    "description": "Custom field values keyed by the custom field's `key` (e.g. `last_name`, not `Last Name`). Unknown keys are ignored and reported in the response `warnings` array.",
+    "type": "object"
+  }
+}
    • changedInput schema / properties / confirm / description
      Previous value: -"Must be true for audience/delivery changes, publishing, destructive operations and signing-secret changes. Use only for an action requested by the user."New value: +"Set true only when the user asked for exactly this action."
    • addedInput schema / properties / fields / $ref
      Added value: +"#/$defs/fields"
    • removedInput schema / properties / fields / additionalProperties
      Removed value: -{
-  "type": "string"
-}
    • removedInput schema / properties / fields / description
      Removed value: -"Custom field values keyed by the custom field's `key` (e.g. `last_name`, not `Last Name`). Unknown keys are ignored and reported in the response `warnings` array."
    • removedInput schema / properties / fields / type
      Removed value: -"object"
    • addedInput schema / properties / payload / properties / fields / $ref
      Added value: +"#/$defs/fields"
    • removedInput schema / properties / payload / properties / fields / additionalProperties
      Removed value: -{
-  "type": "string"
-}
    • removedInput schema / properties / payload / properties / fields / description
      Removed value: -"Custom field values keyed by the custom field's `key` (e.g. `last_name`, not `Last Name`). Unknown keys are ignored and reported in the response `warnings` array."
    • removedInput schema / properties / payload / properties / fields / type
      Removed value: -"object"
  2. First observedv2.0.1

TDQS

A3.6/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare destructiveHint=true, idempotentHint=false and openWorldHint=true, so the safety profile is partly covered. The description still adds real value by enumerating the blast radius — delivery, audience membership, published data, irreversible state — and the confirm requirement, which goes beyond the structured hints.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two short sentences with the tool identified first and the risk/confirmation guidance front-loaded; no filler. It is terse enough that it could have afforded one more sentence of useful context without becoming bloated.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With 8 parameters, nested objects, and no output schema, the description omits the response shape (e.g. the warnings array mentioned only in the schema) and the relationship between the body-flag and payload-based invocation styles. It covers the mutation's risk but not enough for an agent to fully call it correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 63% across 8 parameters, so the schema carries most parameter documentation. The description only surfaces the confirm flag (already documented in the schema) and says nothing about the payload/payload_file alternatives, the fields map, or which attributes are updatable, so it does not compensate for the coverage gap.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb and resource ('Update a subscriber') and hints at the scope of the mutation (delivery, audience membership, published data, irreversible state). It is clear, but it does not distinguish this tool from near-siblings like bulk_update_subscriber_custom_field_values or update_subscriber_location.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

'Requires confirm=true' gives a hard prerequisite and implies the action needs explicit user intent, which is useful gating guidance. However, there is no statement of when to choose this over the sibling update tools or any exclusions.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Deploy Server

Other Tools