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

Annotations already declare readOnly, idempotent, non-destructive and non-open-world, so the safety profile is covered. The description adds genuinely new behavior: it returns a confirmation_token valid for 15 minutes, states what the result contains, and reassures that nothing is sent.

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?

A single dense sentence with the preview-and-no-send guarantee front and center; every clause earns its place. Slightly awkward phrasing ('Checks an email that would send') but no wasted text.

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?

With an output schema present, return values need not be re-explained, and the description adds the token validity window and the no-side-effect guarantee. For a 7-param tool it is complete enough, though it could name the follow-up send step.

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?

Every parameter is already documented at 100% schema coverage, so the schema carries the semantics. The description only alludes to 'who it goes to', adding no syntax or format detail beyond the structured fields, so baseline 3 applies.

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 action (checks/prepares an email offer) on a specific resource (a fare from a flight search), and describes what it returns (recipient, offered fare, confirmation_token). It distinguishes itself from the write path only implicitly via 'Nothing is sent' rather than by naming the send sibling.

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 token plus 'Nothing is sent' implies this is a preview/dry-run step that precedes an actual send (likely egf_send_flight_offer), but neither the alternative nor the when-to-use condition is named explicitly. Usage is inferable but not stated.

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