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

readOnlyHint=true already tells the agent this is a safe read, so the description's remaining burden is lighter. It adds the underlying endpoint (GET /{account}/zones), but says nothing about pagination metadata, default page size, or how many results come back per 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, scope stated first, endpoint appended as a compact aside. No filler or restated field names.

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 simple read-only list tool with full schema coverage and a readOnlyHint, the description plus schema is nearly sufficient. The one gap is that no output schema exists, so the description could have hinted at what a zone record contains, but this is a minor omission.

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% – page, per_page, sort and name_like are all documented in the schema itself. The description's 'with pagination and optional filters' adds no syntax or format detail beyond that, 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 and resource ('List the DNS zones in the account') and notes the tool supports pagination and optional filters, which is enough to separate it from dnsimple_list_zone_records. It stops short of naming or contrasting a sibling explicitly.

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?

There is no when-to-use guidance, no mention of prerequisites, and no routing to alternatives such as dnsimple_get_domain or dnsimple_list_zone_records. The agent must infer that this lists all zones in the account rather than one zone's records.

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