email_forward_update

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states the action (update) and the new destination, but does not reveal side effects such as whether the old destination is replaced, whether the update is idempotent, or what happens if the source rule does not exist. For a mutation tool, this is insufficient.

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, front-loaded sentence with no wasted words. It states the action and the object efficiently, making it immediately understandable. This is a model of conciseness.

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 (2 parameters, no output schema), and the description plus parameter schema cover the core mechanics. However, the absence of annotations and lack of behavioral context (e.g., effects on existing rules, error conditions) leaves some gaps. It is adequate but not fully complete for an update operation.

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 input schema covers both parameters with clear descriptions (source = source address of rule to update, destination = new destination address). The description essentially restates the destination parameter without adding extra semantics. With 100% schema coverage, the baseline of 3 is appropriate; the description adds no further parameter-level detail.

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 uses a specific verb ('Update') with a clear resource ('an existing email forwarding rule') and the specific change ('with a new destination address'). This clearly distinguishes it from sibling tools like email_forward_add (create) and email_forward_remove (delete), and from url_forward_update (different resource type).

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 usage context: updating an existing rule with a new destination. It does not explicitly state when to use this tool versus alternatives (e.g., email_forward_add for new rules), nor does it mention prerequisites like the rule already existing. The guidance is implied but not made explicit.

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