Inxmail MCP

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

No annotations provided, so description carries full burden. Discloses read-only nature, return format (HAL+JSON), and contained fields (complaint type, email, timestamps). Defines what complaints are (spam marking). Lacks rate limits, auth requirements, or error behavior details.

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?

Four sentences with zero waste: purpose (sentence 1), definition (sentence 2), use case (sentence 3), alternative+returns+constraints (sentence 4). Information is front-loaded and every clause earns its place.

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?

Comprehensive for a list tool with 10 parameters: explains domain concept (complaints), distinguishes from sibling, discloses pagination and return format despite lack of output schema. Minor gap: could note that all filters are optional (0 required params) or explain pagination mechanics beyond 'paginated'.

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 has 100% description coverage (all 10 params documented), establishing baseline of 3. Description adds no parameter-specific syntax, validation rules, or examples beyond what schema provides, but does not need to given comprehensive schema coverage.

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?

Excellent specificity: 'List feedback loop complaints for transactional emails' provides exact verb, resource, and scope. Explicitly distinguishes from sibling 'list_relay_complaints' by limiting scope to transactional emails vs mail relay.

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?

Explicit when-to-use guidance: 'Use this to identify recipients who reported transactional emails as unwanted' provides clear intent. Explicitly names alternative: 'For mail relay complaints, use list_relay_complaints instead' prevents tool selection errors.

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