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

With no annotations, the description carries the behavioral burden. It discloses the operation is a DNS MX record fetch via Google DoH, which implies a read-only network query. It does not mention potential rate limits, error behavior, or output format, but these are less critical for a simple DNS lookup.

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 very short and front-loads the key abbreviation 'MX (DoH)' before clarifying it. There is slight redundancy in spelling out DNS-over-HTTPS after already using 'DoH', but overall every word contributes to understanding the tool's purpose.

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?

The tool is simple with one parameter and has an output schema, but the description omits any explanation of the 'q' parameter's expected format. An agent would have to infer that q is a domain name, and no examples or edge-case guidance are provided. The description feels minimal rather than complete.

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 0% and the description does not mention the 'q' parameter at all. The only clue is that 'MX records' implies q is a domain to query, but this is not explicit. The description therefore adds minimal parameter meaning beyond inference from the tool name and purpose.

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 identifies the tool as returning MX records specifically via Google DNS-over-HTTPS, which clearly indicates the resource and method. It distinguishes the tool from generic DNS lookups by focusing on MX record type and DoH backend, though 'lookup' is implied rather than explicit.

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?

Usage context is implied by the phrase 'MX records via Google DNS-over-HTTPS' — an agent can infer this is for MX record lookups over DoH. However, there is no explicit guidance about when to prefer this over sibling tools like 'dnsquery' or 'doh', and no exclusions or prerequisite conditions are stated.

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