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

Annotations already indicate idempotent, non-readOnly, non-destructive. The description adds no further behavioral context, such as whether omitted fields are left unchanged or reset to defaults. It doesn't explain the effect of partial updates despite all parameters being optional. With low annotation coverage, it should elaborate more.

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?

A single, front-loaded sentence that packs all relevant info with no redundancy. It efficiently communicates the tool's purpose and main parameters.

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 11 optional parameters and no output schema, the description is relatively complete but leaves gaps: it doesn't mention whether updates are partial or whole, how the tool handles conflicting values (e.g., budget_min > budget_max), or any defaults. The field list is helpful but not exhaustive, and there's no note about idempotency behavior or return value.

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 only 18%, but the description compensates by grouping parameters semantically: 'where home is' (home_city, home_country_code), 'home airport' (home_airport_code), 'currency', 'nightly budget' (budget_min/max), 'travel pace', and 'working hours' (work_start/end/timezone). It covers most fields, though temperature_preference is omitted. This adds meaning beyond the bare 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?

Description clearly states the action ('Set') and the resource ('standing facts every trip should respect'), listing specific fields like home, home airport, currency, nightly budget, travel pace, and working hours. This distinguishes it from sibling tools that target individual trips or resources.

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?

No explicit guidance on when to use this tool versus alternatives, such as update_journey or other update tools. While it implies it's for global preferences, it never contrasts with siblings or states exclusions (e.g., 'not for per-trip settings'). No when/when-not advice.

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