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

Adds substantial context beyond the destructiveHint and openWorldHint annotations: all fields are replaced, mailCritical records are refused unless force is true, and the call can break the domain's email. It also states the required authorization scope.

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?

Three compact sentences with no wasted text. The replacement behavior, fetch-first prerequisite, mailCritical guard, and auth scope are all front-loaded and easy to scan.

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?

Complete for a destructive update tool: annotations cover safety profile, and the description supplies prerequisites, replacement semantics, authorization needs, and the mailCritical guard. No output schema exists, so return-value omission is not a meaningful gap.

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 description coverage is 100%, so parameter meanings are already well documented. The description reinforces replacement semantics and explains force's mailCritical interaction, but adds little parameter-level detail 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?

States a specific verb and resource: update an existing DNS record in place. It immediately distinguishes the operation from creation or deletion and specifies replacement semantics, so an agent knows exactly what action is being taken.

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?

Provides clear prerequisites: fetch the current record with list_dns_records first, use force true for mailCritical records, and requires the dns:write scope. It does not explicitly name create_dns_record or delete_dns_record as alternatives, but the existing-record condition is clear.

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