Zapmail MCP Server

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It mentions retrieving a list but fails to describe critical traits such as authentication requirements, rate limits, pagination behavior, error handling, or the format of the returned data. For a read operation with zero annotation coverage, this leaves significant gaps in understanding how the tool behaves in practice.

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, stating the core purpose in one clear sentence. The second sentence ('Invoke this endpoint.') is redundant and adds no value, slightly detracting from efficiency. Overall, it's well-structured but could be tighter by removing the unnecessary instruction.

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 (7 parameters, no annotations, no output schema), the description is incomplete. It explains what the tool does but lacks details on behavioral aspects (e.g., auth, limits), output format, and usage context. For a tool with rich input schema but no other structured data, more comprehensive guidance is needed to ensure the agent can use it effectively.

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 input schema has 100% description coverage, so the schema already documents all 7 parameters (e.g., 'method', 'path', 'query'). The description adds no parameter-specific information beyond implying a retrieval action, which doesn't enhance the schema's details. Baseline 3 is appropriate as the schema handles parameter documentation adequately.

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 a list of domains that are still in progress and pending connection with Zapmail.' It specifies the verb ('retrieve'), resource ('domains'), and scope ('in progress and pending connection'), which is specific and actionable. However, it doesn't explicitly distinguish this from sibling tools like 'retrieve_all_domains_13520015e0' or 'list_domains', missing full differentiation.

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 states what the tool does but offers no context on prerequisites, timing, or comparisons to sibling tools (e.g., 'retrieve_all_domains_13520015e0' or 'list_domains'), leaving the agent to infer usage based on the name alone. This lack of explicit when-to-use or when-not-to-use instructions reduces effectiveness.

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