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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered and the 'Read-only' line is reinforcement. The description adds real semantic context the annotations don't: hosted zones are served by Cycle directly, while non-hosted zones only configure LB/TLS and require external DNS management. That distinction materially affects interpretation of returned data.

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-loads the core operation and scope before the explanatory clause, and every sentence carries information. The hosted/non-hosted sentence is longer but earns its place by clarifying data meaning; overall tight, though slightly dense.

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 list tool with no output schema and annotations covering the safety profile, the description supplies the needed operational and semantic context. Return-format details are absent but the absence of an output schema means some expectation-setting could still help; otherwise complete.

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 100%, so the schema already documents 'zone', 'context', and 'conversation_id' fully, including the origin/24-char hex ID format. The description restates the zone dual-behavior but adds no syntax or format detail beyond the schema. 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) and resource (DNS zones/records), plus the scope split: all zones by default, or one zone's records when 'zone' is given. It also distinguishes itself from manage_dns_record, which handles writes, so an agent can route correctly without opening a schema.

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?

Clearly explains the two usage modes (omit 'zone' to list all, supply it to list one zone's records) and names the write alternative manage_dns_record for create/repoint. Lacks explicit when-not-to-use framing beyond the write redirect, so a 4 rather than 5.

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