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. It states the tool returns a list of domains with exact matches and similar domains, but doesn't disclose behavioral traits such as whether it's a read-only operation, requires authentication, has rate limits, or what happens on errors. The description is minimal and lacks critical operational context.

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 two sentences: one substantive and one redundant ('Invoke this endpoint'). The first sentence is front-loaded with key information, but the second adds no value, reducing efficiency. It could be more concise 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 the purpose but lacks usage guidelines, behavioral details, and output information. For a tool with many parameters and no structured safety hints, more context is needed to guide effective use.

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 documents all parameters (e.g., method, path, query). The description adds no parameter-specific information beyond implying TLDs and years of registration are involved, but doesn't clarify which parameters correspond to these or provide additional semantics. Baseline 3 is appropriate as the schema does the heavy lifting.

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: 'returns a list of domains that are available for registration, along with the exact match and a list of similar domains for a given set of TLDs and years of registration.' It specifies the verb ('returns'), resource ('domains'), and scope ('available for registration'), though it doesn't explicitly differentiate from sibling tools like 'check_domain_availability' or 'get_available_domains_25772286e0'.

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 mentions 'for a given set of TLDs and years of registration,' which implies context, but doesn't specify prerequisites, exclusions, or compare it to sibling tools like 'check_domain_availability' or 'get_available_domains_25772286e0'. The phrase 'Invoke this endpoint' is generic and unhelpful.

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