forward-message

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

No annotations are provided, so the description carries full burden. It discloses that with default send=true, the tool sends real email immediately and cannot be unsent, requiring explicit user confirmation. It also describes the return value (confirmation of forwarding or draft saving). This is thorough behavioral disclosure.

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 structured with clear section headers (Use when, Do not use when, Safety) and is front-loaded with the core purpose. Each sentence contributes unique information without redundancy. It is appropriately sized for the tool's complexity.

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's complexity (forwarding email with safety implications), no annotations, and presence of an output schema (so return value details are not needed in description), the description covers all necessary aspects: purpose, usage context, safety warnings, and differentiation from similar tools. It is contextually complete.

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 50% (body and send have descriptions in schema). The description adds meaning for id (forwarding an existing message by id) and to (new recipients, an array), which are not described in the schema. It also reinforces the purpose of body and send as optional and draft-saving. This compensates well for the schema gaps.

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 'forward' and resource 'existing message', and specifies the action: forwarding by id to an array of new recipients with optional prepended body. It distinguishes from siblings like reply-to-message and send-email, meeting the criteria for a specific verb+resource plus sibling differentiation.

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 explicitly provides 'Use when' and 'Do not use when' sections, directly referencing sibling tools (reply-to-message, send-email, create-draft) and explaining the condition for saving as draft (send=false). This is clear and actionable guidance.

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