Mailchimp MCP Server

mailchimp_members_batch_add_remove

Update a Mailchimp segment by adding or removing multiple subscriber email addresses in one batch operation.

Instructions

Batch add or remove members from a segment

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "list_id": "<list_id>",
      "segment_id": "<segment_id>"
    },
    "name": "mailchimp_members_batch_add_remove"
  }
}

Input Schema

Name	Required	Description
`list_id`	Yes	List ID
`segment_id`	Yes	Static segment ID
`members_to_add`	No	Email addresses to add to segment
`members_to_remove`	No	Email addresses to remove from segment

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Aug 2, 2026

TDQS

B3.4/5.0

Behavior2/5

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only states the core mutation (add/remove) without mentioning side effects like whether members must already be on the list, how duplicates are handled, whether the operation is atomic, or what the response looks like. This is a significant gap for a mutation tool.

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

Conciseness5/5

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

The description is a single 8-word sentence that is front-loaded with the verb and resource. There is no filler, redundancy, or unnecessary detail; every word contributes to the core meaning.

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

Completeness2/5

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

Despite complete schema coverage, the tool has no output schema and no annotations. The description is too terse to convey essential behavioral context: what a successful batch operation returns, error conditions (e.g., invalid segment type), or whether both arrays can be used simultaneously. It is minimally viable but lacks critical operating assumptions for an agent to use it reliably.

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?

All four parameters have descriptions in the schema, providing 100% coverage, so the baseline is 3. The description adds no extra semantic detail beyond the schema; it merely indicates the batch nature. It does not clarify relationships between parameters or expected email formats beyond what schema descriptions already state.

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

Purpose5/5

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

The description states a clear action ('Batch add or remove') on a specific resource ('members from a segment'). It distinguishes itself from sibling tools like mailchimp_members_add (single add) and mailchimp_lists_batch_subscribe (list subscription, not segment membership).

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?

The description implies the tool is for batch modification of segment memberships, but it does not explicitly state when to use it over alternatives such as mailchimp_members_add/remove or batch subscribe. No exclusionary conditions or alternative tool names are provided, leaving usage guidance to be inferred from the name and context.

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

Deploy Server