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

Annotations already establish read-only/idempotent/non-destructive, and the description adds genuine behavioral context: the coverageJump flag explains anomalous old registrations appearing at once, and provenance ('same numbers as the Jet Tracker model page and market view') sets expectations. It stops short of describing pagination or performance characteristics.

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?

Dense but front-loaded: the core purpose and return shape come first, defaults and the coverageJump caveat follow, and the sibling pointer is last. Every clause carries information an agent needs.

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 an output schema present, return formatting need not be re-explained; the description covers scope defaults, the coverageJump caveat, and provenance, which is enough to invoke correctly. A note on pagination or output granularity would round it out fully.

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 67%; the schema documents model and scope but leaves months undescribed. The description fills that gap by stating the default (12) and max (120), and reinforces that scope defaults to the whole family. It adds meaning beyond the schema for the one undocumented parameter.

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 ('how the Brazilian fleet of a model moved between monthly RAB snapshots') and enumerates exactly what is returned: entries, mark-reservation/suspended entries, exits, net, per snapshot and total, plus live fleet. It also distinguishes itself from the sibling jt_registry_changes, which covers the underlying aircraft rather than aggregates.

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 clear operating context (default 12 months, max 120, family scope by default) and routes to jt_registry_changes for per-aircraft detail. It does not explicitly say when to prefer this over jt_movements or jt_fleet_stats, so the exclusion guidance is only partial.

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