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 of behavioral disclosure. It states the tool searches for endpoints, but doesn't describe what the search returns (e.g., list of endpoints, metadata), how results are structured, whether it's paginated, or any performance characteristics. This is a significant gap for a search 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 a single, efficient sentence that directly states the tool's purpose without unnecessary words. It's appropriately sized for a simple search tool and front-loaded with the core functionality.

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 search tool with no annotations and no output schema, the description is incomplete. It doesn't explain what the search returns, how results are formatted, or any behavioral traits like error handling. Given the complexity of searching API endpoints, more context is needed to help the agent use it effectively.

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, with clear documentation for both parameters ('keyword' and 'category'). The description mentions 'keywords' (plural) but the schema uses singular 'keyword', and doesn't add any semantic context beyond what's in the schema, such as search scope or result relevance. Baseline 3 is appropriate when 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 as 'Search for API endpoints using keywords to find relevant functionality,' which specifies the verb ('search') and resource ('API endpoints'). It distinguishes from most siblings that perform CRUD operations, but doesn't explicitly differentiate from other search tools like 'search_mailboxes' or 'domain_with_filter_10125073d0' that might have similar search functionality for different resources.

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 any prerequisites, exclusions, or compare it to other search tools in the sibling list (e.g., 'search_mailboxes'), leaving the agent to infer usage based on the resource name alone.

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