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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is fully covered by structured data. The description adds that settlements are 'calculated' (a computed, not stored, result), which is useful context, but says nothing about authorization needs, data freshness, or edge cases. With annotations carrying the behavioral load, a 3 is appropriate.

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 sentence, front-loaded with the verb and resource, listing the concrete outputs with zero filler. Every clause earns its place.

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 summary tool with no output schema, the description adequately enumerates the returned data (totals, per-currency breakdowns, balances, settlements). Annotations cover the safety profile and the schema covers both params, so nothing critical is missing; only deeper behavioral detail is absent.

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% – trip_id and include_settlements are both fully documented, including the default for include_settlements. The description's mention of 'settlement suggestions' loosely maps to include_settlements but adds no syntax or format detail beyond the schema. Baseline 3 when the schema does the heavy lifting.

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 (Get) and resource (trip expense summary) and enumerates the outputs: spend totals, per-currency breakdowns, traveler balances, and settlement suggestions. An agent can tell it apart from siblings like get_travel_stats or trip_details, though it never names an alternative explicitly.

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?

The phrase 'for a trip' and the settlement/balance focus imply when it is useful, but there is no explicit when-to-use, when-not-to-use, or named alternative. Usage is inferred from purpose rather than stated.

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