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

Annotations already cover read-only/idempotent/open-world safety, and the description adds value beyond them: polling behavior, what happens on failure ("what Cloudflare sees if not"), and the semantic meaning of the "active" result. It stops short of stating propagation latency or typical polling cadence, but the behavioral picture is substantially enriched.

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 front-loaded sentences with no filler: the first defines the output surface, the second gives the trigger condition and the meaning of the key result value. Every clause earns its place.

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?

With no output schema, the description correctly takes on the burden of explaining return semantics ("active" means https://<hostname> is live) and the failure path. Slightly incomplete on what non-active states look like and how long verification typically takes before polling again.

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% and the single pageId parameter is already documented as "the pageId returned when the page was published." The description alludes to "a page's" domain but adds no format or sourcing detail beyond the schema, so 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 ("Check a page's custom domain") and enumerates exactly what it reports: connected hostname, DNS verification, SSL certificate state, and Cloudflare diagnostics. This clearly separates it from the mutating siblings custom_domain_set and custom_domain_remove.

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?

Gives concrete timing guidance: "Poll it after the user says the DNS record is in," which tells the agent when to call. It does not explicitly name custom_domain_set/custom_domain_remove as the alternatives for making changes, so exclusion guidance is implied rather than stated.

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