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 the tool retrieves detailed information (status, mailboxes, registration details) and is an endpoint, but lacks critical details like authentication requirements, rate limits, pagination, error handling, or whether it's read-only (implied by 'retrieve' but not explicit). This is inadequate for a tool with 7 parameters.

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, but the second ('Invoke this endpoint.') is redundant and adds no value. The first sentence is front-loaded with the core purpose, but overall structure could be tighter by removing the unnecessary second sentence.

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?

For a tool with 7 parameters, no annotations, and no output schema, the description is insufficient. It lacks details on authentication, error handling, response format, and usage context. The mention of 'detailed information' is vague, and without an output schema, the agent has no guidance on what data to expect.

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 parameter-specific information beyond implying a subscription context, which doesn't compensate for or clarify the generic parameters like 'method' or 'path'. 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 verb ('Retrieve') and resource ('domains allocated to a specific DNS Shield subscription'), making the purpose explicit. It distinguishes from siblings like 'get_available_domains' or 'retrieve_all_domains' by focusing on allocated domains for a subscription, but doesn't explicitly contrast with them.

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 doesn't mention prerequisites (e.g., needing a subscription ID), exclusions, or compare with sibling tools like 'get_eligible_domains' or 'retrieve_all_domains_with_filters', leaving usage context unclear.

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