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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds genuine context beyond that: exit-first ordering, the semantics of entry/exit price (first asking vs last asking on a for-sale portfolio), and the last Windsock value at exit.

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-loads the core purpose and is dense but earnable: the price-semantics sentence is genuinely non-obvious information. The trailing sentence about line_id addressing is useful for chaining but slightly tangential to the listing purpose.

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 values need not be explained, yet the description still orients the agent on row content. For a read-only single-parameter list tool with openWorld semantics and clear sibling hand-offs, nothing an agent needs in order to 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?

Only one parameter with 100% schema coverage, so the schema already documents portfolio_id (and its source, list_portfolios). The description does not add parameter-level meaning beyond repeating that the portfolio_id is derived from list_portfolios. Baseline 3 is appropriate when the schema fully carries the 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 ('aircraft that have left one portfolio') with the exit reasons in parentheses, making it immediately distinguishable from list_portfolio_aircraft (active aircraft). The description also names the sibling it hands off to (get_portfolio_aircraft for full history).

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 clearly frames when this list applies (sold, paid off, listing ended) and points to get_portfolio_aircraft for full history and update_portfolio_aircraft for addressing, which is useful chaining guidance. However, it never states the explicit contrast with list_portfolio_aircraft (active) as an alternative, leaving the sibling selection partly to inference.

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