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

Annotations already declare a safe read (readOnlyHint=true, destructiveHint=false), so the bar is lower, and the description still adds real context: prices are what the operator 'showed Parky on its last check', disclosing staleness/caching, plus the explicit no-booking capability boundary. It does not say what happens when the resort is unsupported or the date falls outside the 365-day window, so behavior at the edges is still undisclosed.

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 short sentences, front-loaded with the trigger, then the return semantics, then the capability limit. Nothing is redundant and every clause constrains how the tool should be used.

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 carries the burden of describing the return, and it does say the result is the last-checked price rather than a live quote. It stops short of indicating what a price record contains (ticket tiers, adult/child, per-day versus per-ticket), which is the remaining gap for a two-parameter lookup.

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 100% and the schema already documents the date format, time zone, default of today, and the resort key/shorthand options, so the description does not need to repeat them. It reinforces the one-year window and the resort vocabulary, which is mild corroboration rather than new meaning — baseline 3.

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 and resource ('what park tickets cost'), names the supported resorts explicitly, and bounds the date range to the next year. No sibling tool covers ticket pricing, and the description makes that distinct scope obvious without opening the schema.

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?

Opens with an explicit trigger condition ('Use this when a visitor asks...') plus the two constraints that qualify a valid request: supported resort and start date within the next year. It also states an exclusion — Parky cannot sell or book — which steers the agent away from promising a purchase flow.

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