Zapmail MCP Server

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

With no annotations provided, the description carries full burden for behavioral disclosure. While it clearly indicates this is a creation/mutation operation, it lacks critical behavioral information: what permissions are required, whether this operation is reversible, what happens if domains already have mailboxes, rate limits, or what the response looks like. For a mutation tool with zero annotation coverage, this is a significant gap.

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 that immediately conveys the tool's purpose without any wasted words. It's appropriately sized and front-loaded with the essential information.

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?

For a mutation tool with no annotations and no output schema, the description is incomplete. It doesn't address critical behavioral aspects like permissions, reversibility, error conditions, or response format. While the purpose is clear, the lack of behavioral transparency makes this inadequate for safe agent use.

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 schema description coverage is 100% with the single parameter 'countPerDomain' well-documented in the schema. The description doesn't add any parameter information beyond what's already in the schema (it doesn't explain the parameter at all). With high schema coverage, the baseline score of 3 is appropriate as the schema does the heavy lifting.

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 specific action ('Create N mailboxes') on specific resources ('every domain in the active workspace with zero mailboxes'). It distinguishes itself from sibling tools like 'assign_new_mailboxes_to_domains_13490321e0' or 'assign_prewarmed_mailboxes_25774338e0' by focusing exclusively on domains that currently have zero mailboxes.

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 clear context about when to use this tool: when you want to create mailboxes on domains that currently have none in the active workspace. However, it doesn't explicitly mention when NOT to use it or name specific alternatives among the many sibling tools, which prevents a perfect score.

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