Mailchimp MCP Server

mailchimp_ecommerce_carts_update

Update an existing ecommerce cart's line items, total, and checkout URL in Mailchimp using store and cart IDs.

Instructions

Update a cart

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": {
      "store_id": "<store_id>",
      "cart_id": "<cart_id>"
    },
    "name": "mailchimp_ecommerce_carts_update"
  }
}

Input Schema

Name	Required	Description
`lines`	No	Updated line items
`cart_id`	Yes	Cart ID
`store_id`	Yes	Store ID
`order_total`	No	Updated cart total
`checkout_url`	No	Updated checkout URL

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Aug 2, 2026

TDQS

C2.6/5.0

Behavior1/5

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, but 'Update a cart' is essentially a restatement of the tool name. It does not disclose whether the update is partial or full replacement, what happens if the cart does not exist, or any authentication or idempotency characteristics.

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

Conciseness3/5

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

The description is a single, short, front-loaded phrase with no redundancy, but it is under-specified to the point of reading like a title rather than a useful description. It is concise but fails to provide substantive guidance, which prevents a higher score.

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?

Given the tool has no output schema and no annotations, the description should provide more context about the operation, such as whether this is a partial update, whether the cart must already exist, and what the response contains. The schema lists fields but does not clarify update semantics, leaving the agent under-informed for correct invocation.

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?

The input schema describes all five parameters with 100% coverage, so the description does not need to explain parameter meanings. However, the description adds no extra semantic value, such as which fields are commonly updated together or how omitted optional fields are treated, leaving the baseline of 3.

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 'Update a cart' clearly identifies the action (update) and the resource (cart), matching the tool name and differentiating it from sibling operations like add, get, delete, or list for carts. However, it lacks any additional context such as which fields can be updated or that it modifies an existing cart, so it stops short of a 5.

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

Usage Guidelines2/5

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

There is no guidance on when to use this tool instead of alternatives like mailchimp_ecommerce_carts_add or mailchimp_ecommerce_carts_delete. The description provides no context about prerequisites, such as requiring an existing cart, nor does it mention that add should be used for new carts.

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

Deploy Server