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

Annotations declare the mutation profile (readOnly=false, destructive=false, openWorld=true, idempotent=false), and the description adds what those hints cannot: the message is delivered by email to a third party and the owner replies to the guest directly, so the agent understands the reply does not come back through this tool. It does not mention failure modes or delivery confirmation.

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 sentences, purpose front-loaded, then usage conditions and required inputs. No filler, no restatement of the title.

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 9-parameter mutation with no output schema, the description covers purpose, usage conditions, and required inputs adequately. The two uncovered parameters (numAdults, numChildren) are partially implied by 'dates, party' in the message field, but are not addressed directly.

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 coverage is 78%, so the schema already documents most fields with useful guidance. The description only restates the required trio (name, email, message), adding no format or constraint detail beyond what the schema provides; numAdults/numChildren remain undocumented in both.

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, resource, and channel: send a guest's enquiry to the site owner by email. No sibling tool in the list (check_availability, get_quote, begin_checkout, etc.) performs messaging, and the description makes the routing role explicit.

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 concrete when-to-use conditions: sold-out dates, questions the listing details leave open, and request-to-book sites. The phrase 'questions the listing details leave open' implicitly routes away from get_listing_details, but no explicit exclusion or alternative is named.

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