Zapmail MCP Server

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

No annotations are provided, so the description must fully disclose behavioral traits. It states the tool retrieves details, implying a read-only operation, but does not cover critical aspects like authentication requirements, rate limits, error handling, or response format. For a tool with 7 parameters and no output schema, this lack of behavioral context 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 concise and front-loaded, consisting of two sentences that directly state the tool's purpose and invocation. There is no unnecessary information, and it avoids redundancy. However, the second sentence ('Invoke this endpoint.') is somewhat redundant with the tool's nature, slightly reducing efficiency.

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 tool's complexity (7 parameters, no output schema, and no annotations), the description is incomplete. It fails to explain the return values, error conditions, or how parameters like 'method' or 'path' override default behavior. For a retrieval tool with many override options, more context is needed to guide effective 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%, meaning all parameters are documented in the input schema itself. The description adds no additional meaning about parameters beyond implying an ID is needed, which is not explicitly stated. With high schema coverage, the baseline score of 3 is appropriate, as the description does not compensate but also does not detract.

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 tool's purpose: 'retrieve the details of a specific mailbox by its ID.' It specifies the verb ('retrieve'), resource ('mailbox details'), and key constraint ('by its ID'), which is specific and actionable. However, it does not explicitly differentiate from sibling tools like 'retrieve_all_mailboxes_13490172e0' or 'search_mailboxes', which offer broader retrieval options, so it misses the top score.

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. It lacks any mention of prerequisites (e.g., needing a valid mailbox ID), exclusions (e.g., not for bulk operations), or comparisons to sibling tools such as 'retrieve_all_mailboxes_13490172e0' for listing all mailboxes. This omission leaves the agent without context for tool selection.

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