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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description earns credit by adding things annotations cannot: results cap at limit (default 5, max 20), prices are whole-aircraft in local currency with estimated taxes and an all-in estimate, operators are deliberately withheld, and inventory churns so results should be re-run rather than cached. That is substantive behavioral context beyond the 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?

Three sentences, front-loaded with the what/where, then what comes back, then the freshness rule. Dense but each clause carries information. The long enumeration of return fields is slightly list-heavy, though it is doing real work given there is no output 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 correctly compensates by enumerating the returned fields (route, departure window, aircraft, seats, price, taxes, all-in, charter comparison, booking link). The one gap is that all nine parameters are optional, yet the description never states which inputs are effectively needed to get meaningful results (e.g. origin/destination/date window).

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 100%, so the schema already documents all nine parameters including formats, bounds and examples; the baseline of 3 applies. The description merely restates the high-level dimensions and the default/max limit, adding no format or interaction detail beyond what the schema provides.

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 ('Search live empty leg flights') and immediately defines the domain term parenthetically as 'whole aircraft, discounted repositioning flights'. The description also scopes the search axes (origin, destination, date window, passengers, market, price ceiling), which cleanly distinguishes it from the single-record sibling get_empty_leg and the pricing sibling get_charter_estimate.

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?

Usage is implied by the search axes and by the note that operators are not named, which tells the agent when this tool won't answer a 'which operator' question. However, no sibling is named and no explicit when-to-use / when-not-to-use condition is given (e.g. 'use get_empty_leg once you have a specific leg id, use get_charter_estimate for non-empty-leg pricing').

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