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

Annotations already cover the safety profile (readOnly, non-destructive, closed-world), so the description's contribution is the added detail: pagination behavior, the { data, total } envelope, and the non-obvious normalization that hyphens are stripped from reg. It stops short of stating page-size caps or what total counts, but it does add real context beyond annotations.

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?

Front-loaded and dense: the resource and its filters come first, return shape last. A couple of terse internal references ("AircraftList scalar") add jargon without adding meaning, but nothing is padded.

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, filter-only read tool with an output schema and read-only annotations, the description covers the discriminating behavior (substring matching, hyphen stripping, sorting, paging envelope). The unmentioned ownopSearch and the absent default page/limit values are the only material omissions, and those are visible in the 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?

With 0% schema description coverage, the description carries the full burden and largely succeeds: it maps regSearch, country (2-letter constraint), icaoSearch/ownop as substring matching, usedBySearch, sortBy, and sortOrder with semantics the bare schema does not convey. Gaps remain — page/limit are only implied by "Paginated", and ownopSearch is never mentioned.

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 resource and operation: "Paginated aircraft directory (AircraftList)" with an enumerated filter set. It is clear what the tool returns, but it never contrasts itself with siblings like Flight_get_aircraft_from_list or Flight_get_aircraft_detail, so the agent must infer the boundary.

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 only implied: the filters (reg, country, ICAO substring, usedBy) suggest this is the browse/search entry point before fetching a detail record. There is no explicit "use this when…" or "use X instead for…" statement, and no mention of the relationship to Flight_get_aircraft_detail.

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