Constant Contact MCP Server and API by Cotlet

Add contacts to list in Constant Contact

constant_contact_add_contacts_to_list

Read-onlyIdempotent

Add contacts to list in the user's own Constant Contact account from ChatGPT, Claude or any AI agent. Returns how to do it in Constant Contact step by step (screens, buttons, fields) and opens nothing by itself; then do it with the cotlet_browser_* tools in the user's Constant Contact Cloud Browser. Constant Contact's official API: Constant Contact has a full public REST API, v3, for contacts, lists, email campaigns and reports, and an official MCP server in beta that is built for transactional email (checked 22 Oct 2026).

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "constant_contact_add_contacts_to_list"
  }
}

Input Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

AddedNov 9, 2026

TDQS

A3.7/5.0

Behavior4/5

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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description reinforces this coherently with "opens nothing by itself". It adds useful behavioral detail the annotations cannot express: the return is a step-by-step guide with screens, buttons and fields, plus the hand-off to browser tools.

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 first two clauses are well front-loaded and earn their place. The trailing sentence about Constant Contact's public REST v3 API and beta MCP server, including a "checked 22 Oct 2026" timestamp, is background trivia that does not help an agent decide or act, and it dilutes an otherwise tight definition.

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

Completeness4/5

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

With zero parameters and no output schema, the description carries the burden of explaining the return value, and it does so (step-by-step screens, buttons, fields). It also explains the intended two-step workflow with the browser tools, leaving only minor gaps about failure modes or what happens if the user is not signed in.

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

Parameters4/5

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

The tool takes zero parameters, so there is no parameter semantics to explain and the baseline of 4 applies. The description correctly avoids inventing arguments and instead spends its words on the output and follow-up workflow.

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?

States a specific verb and resource ("Add contacts to list in the user's own Constant Contact account") and immediately corrects the likely misreading by saying it returns step-by-step guidance rather than performing the action. The only friction is that the name/title imply a mutation while the tool is a guide, requiring the second clause to disambiguate.

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?

It tells the agent the follow-up path ("then do it with the cotlet_browser_* tools in the user's Constant Contact Cloud Browser"), which is real routing guidance. However it never states when NOT to use this versus siblings like constant_contact_create_list, nor how to choose among the many cotlet_browser_* tools.

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

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