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

Annotations already carry the safety profile (readOnlyHint, destructiveHint=false), so the lower bar applies. The description adds real behavioral context: it explains holding.imputed_fields vs holding.unknown_fields provenance, and that archived=true plus departure date/reason/price are returned for departed aircraft. It stops short of rate limits, auth, or pagination behavior.

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 with the return payload, then the provenance and archived clauses. Dense and information-rich, though the two long sentences pack a lot and could be split for scannability.

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 read-only detail fetcher with an output schema present, this covers everything an agent needs: what comes back, the semantics of the provenance fields, and the archived-aircraft branch. Nothing material 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%, so the schema already documents both parameters; baseline is 3. The description adds noteworthy meaning to line_id by noting it can also come from an event or an archived-aircraft listing, but inflation_base gets no treatment beyond the schema.

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?

Opens with a specific verb+resource and scope ('One portfolio aircraft in full') and enumerates exactly what the payload contains. It is immediately distinguishable from the sibling list_portfolio_aircraft because it operates on a single line_id.

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?

It routes the caller explicitly: pass a line_id from list_portfolio_aircraft, or a line_id from an event / list_portfolio_archived_aircraft to get the archived view. That covers both entry points well, though it never states when NOT to use it or what the alternative retrieval tools (get_portfolio_positions, get_portfolio_overview) offer instead.

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