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 mentions filtering domains but fails to describe critical aspects such as required permissions, whether this is a write operation (implied by 'add'), potential side effects, rate limits, or error handling. The description is insufficient for a tool that likely modifies DNS settings.

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 but inefficiently structured. The first sentence is clear, but the second sentence introduces filtering attributes without explaining how they map to parameters, and 'Invoke this endpoint' is redundant. It could be more front-loaded and eliminate unnecessary phrasing.

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, no annotations), the description is inadequate. It lacks details on behavioral traits, does not explain the return values or potential outcomes, and fails to address how the filtering attributes interact with the input schema. For a tool that adds DNS records, more context is needed.

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 schema itself. The description adds minimal value by mentioning 'contains, status and tagIds attribute to filter domains', which loosely relates to some parameters but does not provide additional semantics beyond what the schema already covers. 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 'adds a DMARC record to one or more domains', which provides a clear verb ('add') and resource ('DMARC record'). However, it does not differentiate from sibling tools like 'add_dns_records_13629231e0' or 'add_domain_forwarding_13520843e0', leaving ambiguity about when to use this specific DMARC-focused tool versus other DNS-related tools.

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 includes 'Use contains, status and tagIds attribute to filter domains', which implies some usage context, but it does not provide explicit guidance on when to use this tool versus alternatives (e.g., other DNS record tools), nor does it mention prerequisites or exclusions. The phrase 'Invoke this endpoint' is redundant and adds no practical guidance.

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