Inxmail MCP

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

With no annotations provided, the description carries full disclosure burden. It explicitly states 'This is a write operation,' describes the deduplication semantics (72-hour window), and discloses return values (transaction ID and acceptance status) despite the lack of output schema. Minor gap on error handling or rate limits prevents a 5.

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: 1) purpose/action, 2) operation type/side effects, 3) sibling tool reference, 4) deduplication/returns. Information is front-loaded and every clause provides actionable guidance.

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 write operation lacking annotations or output schema. Covers dispatch behavior, deduplication logic, return values, and post-action verification (get_event_state). Lacks explicit error scenarios or retry semantics, but adequately compensates for missing structured metadata.

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?

While schema has 100% coverage (baseline 3), the description adds crucial semantic context: it clarifies that payload 'must contain a valid email' and explains transactionId's purpose for 'deduplication within a 72-hour window,' adding behavioral meaning beyond the schema's 'Unique ID' description.

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?

Description explicitly states the tool 'triggers a transactional email event' and 'dispatches an actual email' via Inxmail. It clearly distinguishes from siblings like send_raw_mail by emphasizing transactional events versus raw SMTP, and specifies the side effect (actual email dispatch).

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 directs users to 'Use get_event_state with the returned transactionId to check delivery outcome,' providing clear guidance on which sibling tool to use for status checking versus triggering. Also specifies the 72-hour deduplication window constraint.

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