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

Annotations cover readOnly openWorld, and the description adds the critical billing behavior: $0.25 per call charged in USDC from the configured wallet within budget caps, plus a third-party-data trust note. These are real behavioral facts not derivable from annotations. It does not explain what confirm_over_cap does beyond the schema, but that is covered in the schema.

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?

Three compact sentences, front-loaded with scope and then cost/model. Efficient, no filler, though the 'not instructions' note reads as boilerplate rather than earning 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 paid read-only data tool with no output schema, the description covers scope, cost model, and data provenance. Missing value would be an explicit pointer to ski_prices for single-resort lookups, but overall complete enough to call correctly.

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 50%, so half the parameters are undocumented in schema; the description names country/region scope but adds no meaning for state, ageBand, or ticketType. Baseline 3 given partial coverage and the description does not compensate for the undocumented params.

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+scope: lift-ticket prices for many resorts at once, scoped to a country or region. The sibling ski_prices (singular) exists, and the description's 'many resorts at once (a country or region)' implicitly contrasts with a single-resort lookup, but it never names the alternative.

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 country/region scope implies when to use it, but there is no explicit when-to-use vs ski_prices or ski_quote, and no stated prerequisites beyond payment. Usage is inferable rather than stated.

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