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

Annotations already declare readOnlyHint=true and idempotentHint=true, so safety is covered. The description adds valuable behavioral context beyond annotations: authentication is required, and the exact return fields (id, name, type, content, TTL, priority) are specified. This helps set expectations for the response despite no output schema.

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 a single sentence that is front-loaded with the core action and packs in response shape, authentication requirement, and downstream usage. Every clause earns its place; there is no inflated or redundant prose.

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 simple read-only list operation with fully documented parameters and annotations covering idempotence and non-destructiveness, the description is nearly complete. It covers return fields and follow-up actions. Pagination or limit behavior is not mentioned, but this is a minor gap for a low-complexity tool.

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%, with both 'domain' and 'sessionKey' already fully documented in the input schema. The description adds no parameter-specific meaning beyond what the schema provides, so the baseline of 3 is appropriate.

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 states a specific verb and resource: 'List all DNS records for a domain.' It clearly distinguishes itself from single-record operations like getDnsRecord by emphasizing 'all' records. The tool's scope is immediately understandable.

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 clear context on what the tool does and even orients the agent to use returned record ids with getDnsRecord, updateDnsRecord, or deleteDnsRecord. It does not explicitly say when not to use this tool versus alternatives, but the context is strong enough for selection.

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