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

The description says it 'Persists the result,' which is a state-changing side effect, while the annotations declare readOnlyHint=true (no environment modification). That is a direct contradiction between description and structured metadata, warranting the score-1 rule. (The A-record hint is useful, but the conflict dominates.)

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 short, front-loaded sentences: the check, the persistence, then the fallback behavior, followed by group/cost tags. Efficient and easy to scan, with no wasted prose.

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?

An output schema exists, so return values need not be explained, and cost/group are given. However, the definition omits any explicit when-to-use guidance and its persistence claim conflicts with the declared read-only behavior, leaving the agent's safety model ambiguous.

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% — the two generic compact-mode parameters (fields, precision) are fully documented in the schema. The description adds no parameter meaning beyond that, so the baseline of 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 — check whether the configured custom_domain resolves to api.astroway.info via CNAME — which is precise and unambiguous. It doesn't explicitly contrast with siblings such as astroway_whitelabel_config or astroway_whitelabel_preview, so it stops short of full sibling differentiation.

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 only implied: an agent can infer this runs after a custom domain is configured, but the description never says when to call it, when not to, or how it relates to whitelabel_config/preview. The A-record fallback note describes output behavior, not when to choose this tool.

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