check_mx_reputation

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

Annotations already indicate readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is clear. The description adds that it checks multiple RBLs and reverse DNS, which provides useful behavioral context beyond the annotations.

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?

Two sentences pack all essential information: what it checks, the specific blocklists, and differentiation from a sibling tool. No wasted words; very efficient.

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?

With annotations covering safety and idempotency, and an output schema presumably describing the return value, this description is complete. It covers the tool's scope (MX reputation and reverse DNS) and differentiates from a relevant sibling.

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 coverage is 100%—all three parameters have descriptions in the schema. The tool description does not add any additional meaning or detail about the parameters beyond what the schema already provides.

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 clearly states the tool checks whether MX IP addresses are on spam blocklists (Spamhaus, Barracuda, SORBS, and other RBLs) and verifies reverse DNS. It distinguishes itself from the sibling check_rbl, which checks a specific IP directly.

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 guidance: 'Use when you want to know if your mail server IP is blacklisted, or if your MX is on any blocklist.' It also directly contrasts with check_rbl, making it clear when to use this tool instead.

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