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

Beyond the readOnly/non-destructive annotations, the description discloses what is returned (p25/median/p75 in minor units, item count, cheapest published fitting option, build timestamp, seasonNote) and two useful behaviors: unknown places degrade to a list of places that do have figures, and no contact is required. It doesn't explain pagination or the session/email escalation flow, so not a 5.

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?

The core purpose is front-loaded, but the opening sentence is a heavily stacked clause chain strung together with semicolons and commas that is hard to parse on first read. Every element roughly earns its place, but the structure could be broken into shorter, scannable statements.

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 an output schema present the description needn't explain return values, yet it does, and it also covers the unknown-place fallback and contactless operation. However, for an 8-parameter tool it never mentions session, email, or phone escalation ('more rows'), leaving that mechanism to the schema alone.

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%, so the schema already documents all eight parameters including the optional type filter, session, and contact fields. The description restates the place/month/party/type relationship and adds the units context (minor units of the currency), but does not clarify session, email, phone, or name usage beyond what the schema says. 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 resource and what it returns: the p25/median/p75 range of open departures for a place, month and party, plus counts and a cheapest-published figure. An agent can tell this is a price-statistics lookup rather than a booking or listing tool. It doesn't name or differentiate itself from siblings like best_deals, keeping it below 5.

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?

There is no explicit when-to-use or when-not guidance, and no sibling is named as an alternative even though best_deals and search_yachts sit alongside it. The only conditional statements ('An unknown place answers with the places that have figures', 'Works without a contact') describe fallback behavior, not tool selection.

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