Zapmail MCP Server

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

No annotations are provided, so the description carries full burden. It mentions 'invoke' but doesn't disclose critical behavioral traits such as authentication requirements, rate limits, error handling, or whether it's read-only or destructive. For a generic API tool with 8 parameters, this lack of context 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?

The description is a single, efficient sentence that front-loads the core purpose without any wasted words. Every part earns its place by specifying the action, target, and key input methods.

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 (8 parameters, no output schema, no annotations), the description is incomplete. It lacks details on behavioral aspects like authentication, side effects, or response format, making it inadequate for safe and effective use by an AI agent in this context.

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 8 parameters. The description adds no additional meaning beyond implying 'slug' and 'path' as alternative ways to specify endpoints, but doesn't clarify their relationship or usage scenarios. 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 specific action ('invoke') and target resource ('any Zapmail API endpoint'), with explicit mechanisms ('documentation slug or explicit path'). It distinctly differentiates from sibling tools by being a generic API caller rather than a specific operation like 'add_billing_details' or 'get_domain_availability'.

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 implies usage context by specifying 'any Zapmail API endpoint,' suggesting it's for general-purpose API calls. However, it doesn't explicitly state when to use this versus more specific sibling tools (e.g., 'call_endpoint' vs. 'get_domain_availability') or provide exclusions, leaving some ambiguity for the agent.

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