Mailmodo

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

No annotations are provided, so the description carries the full burden. It states it's an 'Add' operation, implying mutation, but doesn't disclose behavioral traits like whether it overwrites existing contacts, requires permissions, handles duplicates, or has rate limits. The description is too brief to provide meaningful context beyond the basic action.

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 a single, efficient sentence with zero waste. It's front-loaded with the core action ('Add Many Contact to a list') and adds clarifying context ('in single API'). Every word earns its place, making it highly concise and well-structured.

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 the complexity (bulk mutation with nested data), no annotations, no output schema, and 0% schema coverage, the description is incomplete. It doesn't explain the return values, error handling, or the structure of 'values' (e.g., contact fields). For a tool with significant parameter complexity, this leaves critical gaps.

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?

Schema description coverage is 0%, meaning parameters are undocumented in the schema. The description adds no information about 'listName' or 'values' parameters, such as format, constraints, or examples. It fails to compensate for the lack of schema documentation, leaving parameters semantically unclear.

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 clearly states the verb ('Add') and resource ('Many Contact to a list'), specifying it's a bulk operation in a single API call. It distinguishes from the sibling 'addContactToList' by emphasizing 'Many' vs. single, though it doesn't explicitly name the sibling. The purpose is specific and actionable.

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?

The description provides no guidance on when to use this tool versus alternatives like 'addContactToList' for single contacts or other list-management tools. It lacks context about prerequisites, such as whether the list must exist or if contacts are created/updated. No exclusions or best practices are mentioned.

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