Inxmail MCP

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

Since no annotations are provided, the description carries full behavioral disclosure burden. It successfully discloses 'Read-only' status (safety profile), 'paginated' behavior, and return format 'HAL+JSON'. Deducting one point because it omits potential rate limits or specific filtering constraints, but coverage is strong for a list endpoint.

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?

Five tightly constructed sentences with zero waste. Information is properly front-loaded with purpose first, followed by usage guidelines, alternative reference, return format, and safety profile. Every sentence earns its place with no redundancy.

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?

No output schema exists, and the description compensates by stating the return format (HAL+JSON) and content type (delivery details). With only two optional pagination parameters and clear sibling differentiation, the description provides sufficient context for invocation, though it could enumerate what specific delivery fields are returned.

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% for both 'size' and 'page' parameters, establishing a baseline of 3. The description mentions 'paginated' generally but does not add semantic detail about the pagination mechanics, cursor behavior, or specific validation rules beyond what the schema already documents.

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 opens with the specific action 'List delivery status records' and the resource 'final delivery outcome for sent emails'. It clearly distinguishes from sibling tool 'check_email_delivery' by contrasting 'high-level overview' versus 'detailed per-recipient diagnostics', satisfying sibling differentiation requirements.

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?

Explicitly states when to use ('for a high-level overview of delivery success/failure across all emails') and explicitly names the alternative tool for different use cases ('For detailed per-recipient diagnostics, use check_email_delivery instead'). Provides clear guidance on tool selection.

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