Zapmail MCP Server

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions retrieving a list with filters but fails to describe critical behaviors like authentication requirements, rate limits, pagination, error handling, or the format of the returned data. This leaves significant gaps for an AI agent to understand how to use the tool effectively.

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 brief and front-loaded with the core purpose in the first sentence. The second sentence ('Invoke this endpoint.') is somewhat redundant but does not significantly detract from overall efficiency. It could be more structured by integrating usage hints.

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 of 7 parameters, no annotations, and no output schema, the description is insufficient. It lacks details on behavioral traits, output format, and practical usage, making it incomplete for effective tool invocation by an AI agent.

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 fully documents all 7 parameters. The description adds no additional meaning beyond implying filtering via parameters like 'query', but it does not explain how filters work or provide examples. 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 states the tool 'Retrieves a complete list of domains available, with filters', which clearly indicates a read operation with filtering capabilities. However, it does not differentiate from sibling tools like 'retrieve_all_domains_13520015e0' (which lacks filters) or 'list_domains', leaving the purpose somewhat vague in context.

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, such as 'retrieve_all_domains_13520015e0' (without filters) or 'list_domains'. It merely states 'Invoke this endpoint', offering no context or exclusions for usage.

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