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

Annotations already cover the safety profile (readOnly, non-destructive, openWorld), so the bar is lower. The description adds genuinely useful behavior the annotations don't carry: the expensive-operation rate limit (300/min) and the underlying GET endpoint. It doesn't discuss response size or pagination for large zones, keeping it from a 5.

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?

Three tight sentences with the scope stated first and the practical backup note and rate limit following. Every sentence carries information; nothing is wasted or repeated.

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 read-only export with annotations carrying the safety profile, the description explains the return format (plain-text BIND zonefile), the scope exclusion (DNSSEC types), and the cost (rate limit). An agent has everything needed to call it correctly.

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?

The single 'domain' parameter is fully documented in the schema (100% coverage), so the schema does the heavy lifting. The description adds only the endpoint path showing where the name goes, not new semantics. Baseline 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?

States a specific verb (export) and resource (the whole zone as a BIND-format zonefile), and pins the scope precisely: 'all RRsets except DNSSEC types.' This clearly distinguishes it from siblings like desec_get_rrset or desec_list_rrsets, which operate at the RRset level rather than the whole zone.

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?

'Handy as a backup before changing records' gives an explicit when-to-use context, which is more than most tools offer. It doesn't name a sibling alternative or an exclusion case, so it falls short of a full 5.

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