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

Goes well beyond the annotations: per-call USDC billing from a configured wallet, enforcement of session/daily budget caps, and the confirm_over_cap escape hatch for clients that can't prompt the user. It also flags results as third-party data rather than instructions, which is valuable prompt-injection guidance not covered by readOnlyHint/openWorldHint.

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?

Four short, front-loaded sentences covering identity, cost, payment mechanics, and a safety note. Nothing is redundant and the most decision-relevant facts (what it returns, that it costs money) come first.

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 no output schema, the description still conveys the resource returned (published lift-ticket prices) and all cost/permission behavior an agent needs before calling. It doesn't describe result shape or pagination, but for a single-resort price lookup with full schema coverage that gap is minor.

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%, so the schema already documents country, resort, state, and confirm_over_cap. The description adds only two things: where resort ids come from and the billing context around confirm_over_cap, which is marginal over the schema's own text. Baseline 3 is appropriate.

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 (published lift-ticket prices) and scopes it to "one ski resort", which implicitly separates it from ski_prices_bulk and ski_quote. It stops short of naming the sibling it is not, so an agent must infer the contrast from scope wording alone.

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?

Gives clear operative context: cost per call, product code, and the routing hint that resort ids come from ski_coverage, which is free. It doesn't state when NOT to use this tool (e.g., bulk or multi-resort needs), but the when-to-use signal is strong.

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