Get Catch-All

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. The description adds real context by decoding the returned setting: the three `type` values with their mail-handling meaning and the conditional nullity of `address`. It stops short of stating error behavior for an unknown domain or any account/permission 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?

Two compact sentences: the purpose first, then the value semantics. Every clause carries information an agent would otherwise have to guess from the enum values, and there is no filler.

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 one fully documented parameter, safety annotations, and an output schema, the remaining burden is small, and the description covers the interpretation of the returned values. The only gap is failure behavior (nonexistent domain, insufficient permissions), which an agent might want before calling.

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 `domain` parameter is already documented with format constraints (letters, digits, hyphens, at least one dot). The description contributes no additional meaning about the parameter, so the baseline of 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 ("Returns the domain's catch-all setting") and immediately defines the resource in domain terms ("how mail addressed to nonexistent local parts is handled"). This distinguishes it cleanly from the write-side sibling set_catch_all and from unrelated getters like get_spam_settings.

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?

Usage is only implied: an agent can infer this is the read counterpart to set_catch_all, but the description never says when to call it (e.g., to inspect current routing before changing it) or what to do if the domain is missing. No exclusions or prerequisites are stated.

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