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

Annotations already establish readOnly, idempotent and non-destructive behavior, so the bar is lower; the description still adds meaningful context by stating the data comes from regulators' published lists and that bookings are sourced through these operators. It omits pagination/limit behavior, but the value-add beyond the annotations is real.

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 with no filler: the first front-loads what is returned and how it can be filtered, the second immediately routes the agent elsewhere for trips. Nothing is padded or repeated.

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 carries the return-value burden and does so by enumerating the fields returned, including the profile page. It also names the sibling to use for booking, leaving little an agent needs beyond the already-complete input schema.

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 all four parameters are already documented in the schema with defaults, bounds and an enum. The description restates the filter axes (market, base city, aircraft size) without adding format or constraint detail, which is the expected baseline when the schema does the heavy lifting.

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?

The description names the exact resource (licensed charter operators), its provenance (regulators' published lists), the filter dimensions (market, base city, aircraft size) and the returned fields (name, base city, licence type, fleet, profile page). It is clearly distinct from request_quote, though it never addresses the potential overlap with list_aircraft and fleet models.

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?

"For trips, use request_quote" gives an explicit alternative plus the condition that selects it, and the closing clause explains the relationship between the two tools. It offers no guidance on when to prefer this over list_aircraft or get_charter_estimate, so it stops short of full when/when-not coverage.

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