imap_list_spam_domains

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

With no annotations, the description carries the burden, and it clearly indicates a read-only enumeration ('List all known spam domains'). It also adds scope ('built-in and custom') beyond what a bare name would imply. It doesn't mention output format or auth, but for a zero-parameter list operation this is adequate.

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?

A single, front-loaded sentence with zero filler. 'List all known spam domains' immediately conveys action and object, and the parenthetical clarifies domain membership.

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?

For a simple, parameterless read tool without an output schema, this is nearly complete. It would be fully complete with one explicit statement of return format (e.g., array of domain strings), but the behavior and scope are clear.

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 schema has no parameters and schema coverage is 100%, so parameter documentation is not needed. The 0-parameter baseline is 4; the description doesn't need to compensate.

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?

Description uses specific verb 'List' and clearly identifies resource as all known spam domains, including built-in and custom. This distinguishes it from sibling tools that manage, delete, or check spam, even without naming them.

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?

The description implies use when the agent needs to enumerate known spam domains, but it offers no explicit when-to-use guidance or exclusions against similar siblings like imap_domain_stats or imap_check_spam. Context 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.