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

Adds real context beyond the annotations: attachments bypass the chat, the comment is placed above the forward, and recipients are constrained by send_allowlist. This is meaningful behavioral disclosure for a destructive/openWorld tool, though reversibility and failure modes are not addressed.

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 tight clauses with zero filler, and the core action plus its distinguishing trait (attachments not passing through the chat) is front-loaded before the constraints.

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?

Covers the salient behaviors for a 10-parameter send tool and annotations carry the safety profile, but with no output schema and 30% of parameters undocumented, an agent gets no help on recipient limits or the folder default.

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?

At 70% schema description coverage the schema already documents comment, as_draft, subject, folder, and include_attachments. The description mostly restates comment placement and as_draft rather than extending them, and says nothing about the cc/bcc/to recipient arrays or their 50-item cap. Baseline 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?

States a specific verb (forwards) and resource (a message) plus its full payload (all its attachments). 'Forward' is clearly distinct from the send_message/reply_send/create_draft siblings, so an agent can route to it without opening another schema.

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?

Gives a hard precondition ('Recipients must match send_allowlist') and explains the as_draft variant, but never states when to prefer this tool over reply_send, send_message, or create_draft. Usage is implied by the verb rather than explicitly framed as a routing decision.

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