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

Annotations already declare read-only, idempotent, non-destructive and closed-world; the description adds provenance per figure (engine program, published intervals, CENIPA/NTSB/ASN) and, importantly, a hard limitation that no airframe or engine hours exist so no due-date can be derived. That caveat prevents a serious misuse mode the annotations could never convey.

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?

The opening clause front-loads the resource and the parenthetical enumerations replace what would otherwise be several paragraphs, so density is earned. The middle section is a long run-on with nested parentheses and acronyms (TBO, HSI, RBAC 145) that slightly impedes scanning.

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 values need no explanation; the description instead covers what the tool will not do (no tail-level hours or due dates), where each figure comes from, and where to go for the per-aircraft case. Nothing an agent needs to select and call it correctly is missing.

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 100% and the single `model` parameter is described in the schema, including its format and its source (jt_model_search). The description adds no syntax, format, or validation detail beyond that, so the baseline of 3 applies.

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 — a maintenance reference for one catalog model — and then enumerates exactly what figures it returns (engine program TBO/HSI hours, overhaul reserve, published intervals, ANAC 145 shop counts, accident/incident totals). It explicitly frames the scope as model-level, which separates it from the per-tail tools without the agent needing to open a schema.

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 a clear use case ('MRO, insurer, lender or buyer questions about a type') and names the alternative for the adjacent need ('the events of one tail are in jt_aircraft_history'), plus an explicit exclusion ('never says when a given aircraft is due'). It does not differentiate from overlapping siblings like jt_maintenance_signal or jt_mro_capabilities, which cover adjacent maintenance/shop data.

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