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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds the useful 'DNS is the same in every zone' scoping fact and the endpoint, but says nothing about pagination behavior or how large result sets behave, which the schema only hints at ('The API itself returns whole lists').

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 compact sentences, front-loaded with the action and result shape, with the zone-scoping caveat immediately after. Nothing is wasted and nothing is buried.

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?

There is no output schema, so the description's enumeration of returned fields (id, unicode name, creation date) is genuinely load-bearing, and annotations plus the schema cover safety and pagination parameters. Minor gap: it does not characterize result volume or typical pagination needs for a list endpoint.

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 limit and offset are fully documented in the schema itself, including default values and the next_offset convention. The description adds no parameter guidance, so the 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?

States a specific verb ('List'), resource ('DNS domains (zones)'), plus the fields returned (id, unicode name, creation date) and the underlying endpoint (GET /dns-domain). This clearly distinguishes it from the singular exoscale_get_dns_domain and from exoscale_list_dns_records.

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?

Usage is implied by the 'List' verb and the explicit note that 'DNS is the same in every zone', which usefully tells the agent no zone parameter is required. However, it never names the alternative exoscale_get_dns_domain for a single domain or exoscale_list_dns_records, nor states any when-not-to-use condition.

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