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

Annotations only declare destructiveHint=true; the description adds meaningful context beyond that: it opens with 'WRITE', states the change 'Takes effect on live DNS', and the keep-the-fields-you-want instruction implies full-replacement (PUT-style) semantics rather than a partial patch. It stops short of stating auth requirements or irreversibility explicitly.

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?

Front-loaded with the 'WRITE' marker, followed by purpose, effect, workflow, and endpoint in four tight sentences. Every sentence carries distinct information with no redundancy.

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 15-parameter mutation tool with no output schema, the description covers the essentials: write nature, live impact, read-before-write flow, and API mapping. It leaves return-value behavior unstated, but with no output schema that is a minor 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 all 15 parameters are already documented in the schema (including type-specific usage for flags, port, priority, etc.). The description only echoes the required type/name/value trio and adds no per-parameter meaning, so baseline 3 applies.

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?

Names a specific verb+resource ('Update an existing DNS record') and scopes it to existing records, which implicitly separates it from bunny_add_dns_record. The live-DNS impact statement sharpens the purpose. It does not explicitly contrast against the add sibling, keeping it at 4 rather than 5.

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?

Gives an explicit workflow prerequisite: read the record first with bunny_list_dns_records and carry over fields you want to keep. This is actionable when-to-use guidance with a named alternative. No explicit when-not-to-use or guidance against bunny_add_dns_record, so not a 5.

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