Change DNS Zone RRSet TTL

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

Annotations already convey that this is a mutating, non-destructive, idempotent operation, so the description does not need to restate that. However, it adds no behavioral context beyond the null-fallback behavior, which is already in the schema description. There is no mention of propagation, permissions, or side effects on existing records.

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 with no wasted words. It leads with the core action and then adds the key exception/nuance. This is an appropriately sized and well-structured description.

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 single-attribute mutation with complete schema coverage and helpful annotations, the description is sufficient. It captures the core behavior and the null special-case. It could be slightly richer about relationship to zone-level TTL or expected effects, but nothing critical is missing for correct invocation.

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 every parameter is already documented. The description's 'ttl=null to fall back to the zone default TTL' repeats what the schema already says. The description adds no semantic value beyond the structured 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 states a specific verb and resource: 'Change the TTL of an RRSet.' It also adds the meaningful null-fallback behavior, clarifying the scope of the operation. It does not explicitly contrast with the sibling change_zone_ttl, but the RRSet-specific focus makes the purpose clear.

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 implies this tool is for per-RRSet TTL changes, and the phrase 'zone default TTL' hints at a zone-level alternative. However, it does not explicitly say when to use this tool versus change_zone_ttl or other RRSet tools. The usage guidance is only implied, not stated.

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