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

Annotations already mark as destructive. The description adds that changes take effect immediately for real resolution and that only provided fields are sent (partial update). This adds valuable behavioral context beyond 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 efficient sentences: first states purpose, second provides warning and implementation detail. No redundant information.

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?

Given 7 parameters, no output schema, and annotations, the description covers the essential behavioral traits (live DNS mutation, partial update) and references the API method. Could mention return values, but output schema absence is noted.

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 the schema already documents parameters. The description mentions partial update ('Only the fields you provide are sent') but does not add meaning to individual parameters beyond what's in the 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 clearly states the action: 'Update an existing DNS record.' It also provides the API endpoint, distinguishing it from sibling tools for creating or deleting records.

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 includes a strong warning about mutating live DNS, which guides when to use with caution. However, it does not explicitly contrast with sibling tools like create or delete, though the context is clear.

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