Add a contact to a Mailmodo list by providing email and list name, with optional fields for personal details such as name, birthday, phone, address, and more.
Add Contact to list
| Name | Required | Description | Default |
|---|---|---|---|
| data | No | ||
| Yes | |||
| listName | Yes | ||
| timezone | No | ||
| last_open | No | ||
| created_at | No | ||
| last_click | No |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations and no description of side effects, permission requirements, or behavior when a contact already exists, the tool is completely opaque. The agent cannot infer mutation or idempotency.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is extremely short, but at the cost of necessary information. It fails to be concise in a meaningful way; it is under-specified and does not earn its place.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given no annotations, no output schema, and an incomplete parameter set, the description is wholly inadequate. It fails to explain return values, error conditions, or when the operation succeeds.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The description adds no meaning to the parameters. Although the input schema has descriptions for nested data fields, the top-level parameters (email, listName, created_at, etc.) remain undocumented. With 0% schema description coverage and 7 parameters, the lack of param information is a critical gap.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description 'Add Contact to list' is a tautology that merely restates the tool name without adding specificity or clarifying what kind of list or what scope. It offers no distinction from sibling tools like addBulkContactToList.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No guidance is provided on when to use this tool versus alternatives such as addBulkContactToList or other contact management tools. The description omits any context about prerequisites, typical use cases, or exclusions.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.