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

Annotations already declare readOnly/non-destructive/openWorld, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: it explains that imputed_fields marks facts Windsock inferred (estimated or FAA registry) vs holder-provided, and unknown_fields marks facts cleared or unreadable — real data-provenance semantics an agent could not infer.

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 and front-loaded with the returned resource, then provenance and pagination. The imputed/unknown-fields sentence is long but earns its place by defining a non-obvious data model; nothing is redundant filler.

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?

An output schema exists, so return-value enumeration is bonus rather than requirement, and the description still supplies the semantic meaning of returned fields plus pagination. For a read-only list tool with annotations and an output schema, this is complete; only the sibling-choosing guidance 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 description coverage is 100%, so the schema already documents limit, cursor and portfolio_id. The description reinforces pagination via next_cursor and the default page size, but adds no syntax or format detail beyond the schema, so baseline 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+resource (list the aircraft in one portfolio) and enumerates the returned facts, letting an agent know exactly what this returns without opening a schema. It partially distinguishes itself from siblings by noting line_id addresses aircraft in the other portfolio tools, but it never contrasts against get_portfolio_aircraft or list_portfolio_archived_aircraft, leaving some ambiguity about which variant to pick.

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 description explains the shape of the data and points at 'the other portfolio tools' as consumers of line_id, but never states when to choose this over list_portfolio_archived_aircraft or get_portfolio_aircraft. No prerequisites or exclusions are given.

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