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

Annotations already indicate readOnlyHint=true and destructiveHint=false, so the safety profile is clear. The description adds that it returns the default domain and ids, which is useful. However, it doesn't mention the output schema's structure (which exists), so the agent may not know the exact format of the response. The description adds some value beyond annotations but not extensive.

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?

One sentence, front-loaded with the main function. It includes specific details (default, ids) without verbosity. It could be slightly more structured but is efficient.

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?

The tool is simple (no params, read-only) and has an output schema, so the description doesn't need to explain return values. It covers the purpose and key output aspects. Given the low complexity, the description is sufficient for an agent to call it correctly.

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?

The tool has no parameters, and schema description coverage is 100% (empty schema). The description provides context that the tool returns default and domain_id values, which adds meaning to what the tool returns, but there are no parameters to explain. With zero params, a 4 is appropriate as the description informs about return values that are otherwise not in the schema.

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 ('List link domains'), and clarifies that it returns domains, the default, and their ids for domain_id. Distinct purpose, no ambiguity.

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?

Implied usage is to retrieve domains info when the agent needs to know domain_id or default domain. No explicit guidance on when NOT to use or alternatives, but the narrow scope makes it clear it is for listing domains only, unlike other sibling tools which are for QR codes and account info.

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