add_forward

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

With no annotations, the description carries the full burden of behavioral disclosure. It only says 'Add', which implies a mutation, but does not explain whether adding is idempotent, whether it replaces an existing forwarding address, whether it triggers any verification, or what the result of the operation is.

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, efficient sentence that states the core purpose without unnecessary detail or repetition. It is well front-loaded and easy to parse.

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 three-parameter creation tool with a fully documented schema, the description is minimally viable. However, because there are no annotations and no output schema, it would be stronger to mention likely duplicate behavior, whether the mailbox must already exist, or the operational effect of the forwarding rule.

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 100%, so the parameters are already well documented in the schema. The description itself adds no parameter-level meaning beyond what the schema provides, so the baseline of 3 is appropriate.

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 states a clear verb ('Add') and resource ('a forwarding address to a mailbox'), and the sibling tools list_forwards and remove_forward make the operation distinct. An agent can immediately understand this creates a forwarding relationship rather than listing or removing one.

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. It does not mention that list_forwards is for viewing existing forwards or that remove_forward is for deleting them, nor does it state any prerequisites such as the mailbox needing to exist.

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