list_forwardings

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and idempotentHint=true, so the agent knows it is a safe, read-only operation. The description adds the detail 'external forwardings', providing some context beyond the schema. However, it does not disclose behavior like pagination or ordering, which is acceptable given the annotations cover safety.

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 a single sentence that immediately conveys the core purpose with no extraneous words. It is efficient and front-loaded, making it easy for the agent to parse quickly.

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 tool is a simple list operation with two parameters and no output schema, the description covers the basics. However, it does not explain the effect of the domain parameter, whether results are ordered, or if there are limits. For a simple tool, this is adequate but leaves minor gaps that could be clarified.

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 description coverage is 0%, so the description must clarify parameter meanings. It only implies the 'mailbox' parameter via the phrase 'on a mailbox', but does not explain the optional 'domain' parameter or its purpose. This leaves ambiguity about how the tool filters or scopes results.

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 the verb 'List' and the resource 'external forwardings', specifying the scope 'on a mailbox'. It distinguishes itself from sibling tools like list_aliases or list_domains by focusing on forwardings, and the qualifier 'external' adds specificity.

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 provides no guidance on when to use this tool versus alternatives such as get_forwarding (for a specific forwarding) or list_rewrites. There is no mention of prerequisites (e.g., mailbox existence) or context that would help an agent decide between listing and retrieving a single forwarding.

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