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 adds nothing about safety, permissions, rate limits, or what 'domain with filter' entails. The vague statement fails to inform the agent about the tool's behavior or potential side effects.

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?

While concise with a single sentence, the description is under-specified and fails to convey useful information. It lacks front-loaded clarity and wastes the opportunity to explain the tool's purpose, making it ineffective despite its brevity.

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 annotations, no output schema), the description is completely inadequate. It does not compensate for the lack of structured data, leaving the agent without necessary context for proper tool invocation.

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 100%, so the schema fully documents all 7 parameters. The description adds no additional meaning beyond what the schema provides, such as explaining how parameters interact or typical use cases. This meets the baseline for high schema coverage.

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 'Invoke this endpoint' is a tautology that merely restates the tool's function without specifying what it actually does. It fails to distinguish this tool from sibling tools like 'call_endpoint' or explain what 'domain with filter' means, providing no meaningful purpose statement.

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. With sibling tools like 'call_endpoint' and many domain-specific tools (e.g., 'retrieve_all_domains_with_filters_26049361e0'), the description offers no context for selection, leaving the agent without usage direction.

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