update_rrset_records

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

Annotations already declare this is a non-read-only, idempotent, non-destructive mutation, so the safety profile is covered. The description adds real value by disclosing the matching rule ('matched by value') and the write scope (comments only), but leaves open what happens when a supplied value does not match an existing record — error, skip, or create — which matters for a mutation call.

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 short sentences with zero filler, and the core constraint is front-loaded before the pointer to the alternative tool. Every clause carries information an agent needs.

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 four-required-parameter mutation tool with no output schema, the definition covers the essential semantics but omits error/unmatched-value behavior and any indication of what the call returns. It is adequate to call correctly in the happy path but not fully complete for handling edge cases.

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 only 50%, with 'type' and 'records' undocumented in the schema. The description compensates for the most consequential gap by explaining that each record is identified by its value and that only the comment field is writable, effectively documenting the two nested fields of the records array.

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 ('Update the comments of existing records') and narrows scope to comments only, which is more precise than the tool name alone suggests. It differentiates from set_rrset_records by name, though it does not distinguish itself from the closely named sibling update_rrset.

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?

It gives an explicit when-not ('Cannot change values') and names the correct alternative for that case ('use set_rrset_records for that'), which is exactly the routing an agent needs. It stops short of explaining when to prefer this over add_rrset_records or remove_rrset_records.

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