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

Annotations only declare readOnlyHint=false/openWorldHint=true/destructiveHint=false, but the description adds substantial behavior: nothing is offered or agreed, the buyer receives an email link, the message is delivered only after confirmation (double opt-in), and the representative replies directly. It also discloses the conditional needs_answers round-trip, which is behavior an agent could not infer from structured fields.

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?

Four sentences, purpose front-loaded, each carrying distinct information (purpose, precondition, delivery mechanics, qualification flow). Slightly dense but nothing is wasted; no filler or repetition of the schema.

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 no output schema, the description compensates by explaining the only meaningful return path (first call returns needs_answers with the owner's questions) and the confirmation-link delivery flow. It is close to complete for this tool, though it does not say what a normal (non-qualified) successful call returns.

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 already 100%, so baseline is 3, but the description adds real meaning beyond the schema: it ties name/email/message to the person being helped, and crucially explains that 'answers' must be supplied in the order the tool returned the questions on a second call. That sequencing rule is not obvious from the schema item description alone.

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 and resource: it 'passes a would-be buyer's message about acquiring one aircraft to the acquisition representative its owner named.' This is clearly distinguishable from siblings like get_aircraft, search_aircraft, estimate_charter, check_availability and request_trip, which cover other lifecycle steps.

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 an explicit precondition: 'Call it only after the person you are helping has asked to contact the owner, with their own name, email and message,' and explains the two-call sequence when qualification questions exist. It does not name an alternative sibling tool or restate when not to reach for this one, so it falls short of a full 5.

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