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 states this is an enablement action ('enables email forwarding'), implying a write/mutation operation, but doesn't disclose critical behavioral traits: whether it requires specific permissions, if it's idempotent, what happens to existing forwarding settings, rate limits, or error conditions. The description is insufficient for a mutation tool with zero annotation coverage.

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 appropriately concise with three sentences that efficiently explain the tool's function. The first sentence states the purpose, the second explains email forwarding, and the third is a generic call-to-action. While 'Invoke this endpoint' adds little value, the overall structure is front-loaded and wastes minimal space.

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 mutation tool with 7 parameters, no annotations, and no output schema, the description is incomplete. It explains what email forwarding is but doesn't cover behavioral aspects (permissions, side effects), parameter usage, expected outcomes, or error handling. The context signals indicate significant complexity that the description fails to address adequately.

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 description adds no parameter-specific information beyond what's already in the schema (which has 100% coverage). It mentions 'one or more registered domains' and 'designated recipient address', but these don't map to any of the 7 documented parameters (e.g., method, path, body). With complete schema coverage, the baseline score of 3 is appropriate as the description doesn't enhance parameter understanding.

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: 'enables email forwarding for one or more registered domains' and explains what email forwarding does ('redirects all incoming emails... to a designated recipient address'). It distinguishes from some siblings like 'remove_email_forwarding_13521037e0' by specifying the enable action, though it doesn't explicitly differentiate from all similar tools like 'add_domain_forwarding_13520843e0'.

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., domain registration status), when not to use it, or compare it to sibling tools like 'add_domain_forwarding_13520843e0' or 'enable_catch_all_emails_13521061e0'. The phrase 'Invoke this endpoint' is generic and adds no contextual guidance.

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