List custom domains

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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. Beyond that, the description explains the status state machine (pending_dns until DNS records are in place, then live; verified once ownership is proven) and the plan gate (Scale and Enterprise) plus the limit, which an agent cannot infer from the schema. It does not cover empty-workspace behavior or auth requirements.

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 'Read-only.' followed by what is returned and then the use case, in three dense sentences with no filler. The parenthetical explanations of statuses are long but each earns its place by preventing misinterpretation of enum-like values.

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 must describe returns itself — and it does: domain names, status values, required DNS records, plan eligibility and limit. An agent can decide and act without further information.

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?

Zero parameters, so there is nothing to disambiguate and the baseline of 4 applies. The description correctly adds no parameter noise and instead spends its space on return-value semantics.

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 ('The workspace's custom link domains') and enumerates what each entry contains: status and the exact DNS records to add. It is clearly distinguishable from the mutation siblings add_domain/remove_domain.

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 a concrete trigger phrase, "is my domain set up yet", which tells the agent exactly when to reach for this tool. It stops short of naming alternatives or exclusions (e.g. use add_domain to create one, remove_domain to delete), so it is clear context without full routing.

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