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

With no annotations provided, the description carries full responsibility for side-effect disclosure. It clearly states 'This is a READ: it never reserves, registers, or charges anything,' and explains the meaning of premium and renewal_price cliff, offering rich behavioral context beyond what annotations could provide.

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?

The description is front-loaded with the purpose and usage, then explains return field semantics, then states the read-only nature. Each sentence earns its place with no redundancy or wasted wording.

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?

Given the simple one-parameter schema and the presence of an output schema, the description provides complete context for correct invocation. It names the key return fields, explains how to interpret premium and renewal_price, and clarifies the tool's non-mutating behavior.

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 0%, so the description must compensate. It specifies the parameter should be an 'exact domain' with the example 'orivox.ai', adding meaning beyond the bare string type. However, it leaves some ambiguity about acceptable formats (e.g., protocol, path, wildcards), so it is not fully exhaustive.

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?

The description clearly states it performs an 'authoritative availability check for ONE exact domain' and gives a concrete example. It explicitly differentiates from search_domains by directing usage to this tool when a specific domain is named.

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?

It explicitly says 'use this, not search_domains, when the user names a specific domain,' providing clear when-to-use guidance. It also instructs on how to handle output, such as quoting premium pricing and always telling the user both price and renewal_price.

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