Inxmail MCP

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

No annotations provided, yet description fully discloses: management mechanism ('managed by Inxmail — addresses are added automatically'), safety profile ('Read-only'), and return format ('paginated HAL+JSON with email and block date'). Exceeds baseline requirements.

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 sentences cover: purpose, management logic, sibling distinction, alternatives, and return format. Zero filler. Front-loaded action verb. Each sentence advances understanding of tool behavior or selection criteria.

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?

Despite missing output schema, description fully specifies return format (HAL+JSON structure, pagination, fields included). Covers domain concepts (hard bounces vs manual blacklisting), safety, and pagination behavior. Complete for a list operation with 4 parameters.

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% coverage, establishing baseline 3. Description adds contextual value by stating 'Returns paginated' (clarifying size/page purpose) and implying date filtering scope without redundantly listing parameters. Slight boost for contextual framing.

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?

Opens with specific verb+resource ('List email addresses automatically blocked due to hard bounces') and immediately distinguishes from sibling 'blacklist' tool ('Unlike the blacklist (manually managed)...'). Clearly defines scope as automatic hard-bounce blocks.

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 names alternatives with specific use cases: 'Use get_blocklist_entry to check a specific email, or check_email_blocked for a combined check.' Also contrasts blocklist (automatic) vs blacklist (manual) to guide correct selection.

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