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. The description only hints at invoking an endpoint but fails to explain critical behaviors such as authentication requirements, error handling, rate limits, or what the tool returns. For a tool with 7 parameters and no output schema, this lack of detail 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?

While the description is short, it's under-specified rather than concise. The single sentence 'API Docs Invoke this endpoint' is vague and doesn't front-load useful information. It fails to earn its place by providing actionable details, making it inefficient 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 incomplete. It doesn't explain the tool's purpose, usage, or behavior adequately. Without annotations or output schema, the description should provide more context to help the agent understand how to use this tool effectively, which it fails to do.

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 or context about the parameters, such as examples or usage notes. Given the high schema coverage, a baseline score of 3 is appropriate, as the description doesn't compensate but also doesn't 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 'API Docs Invoke this endpoint' is vague and tautological—it essentially restates the tool name 'Zapmail Docs' without specifying what the tool actually does. It doesn't clearly state a verb and resource (e.g., 'make HTTP requests to the Zapmail API'), nor does it differentiate from sibling tools like 'call_endpoint' or other API-related tools in the list.

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?

There is no guidance on when to use this tool versus alternatives. The description provides no context, prerequisites, or exclusions, and it doesn't mention sibling tools like 'call_endpoint' that might serve similar purposes. This leaves the agent with no information to make an informed choice.

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