Create MX Record

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

The description discloses the critical nondestructive behavior: it overwrites all existing MX records with the same name, not merges them. This goes beyond the destructiveHint annotation (which is true) by explaining the exact effect and disruption to email delivery, providing complete transparency.

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?

The description is two sentences and a warning, all essential and front-loaded. No fluff; every word adds useful context. The warning is prominently placed and clear.

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?

For a destructive mutation tool with no output schema and 5 parameters, the description fully covers the behavioral impact, prerequisites (check existing records), and potential consequences (email disruption). No gaps remain.

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%, with each parameter described in the schema (name, domain, exchange, priority, ttl). The description does not elaborate further on parameters, so it meets the baseline without adding extra semantic value beyond schema.

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 explicitly states it creates an MX record (mail exchange), specifying the resource type. It is clear and distinct from sibling tools like create_a_record, create_cname_record, etc., which serve different DNS record types.

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?

The description provides explicit guidance: it warns that using this tool replaces all existing MX records with the same name, and advises using list_dns_records first to check for existing records. This tells the agent exactly when and how to use it safely.

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