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

Annotations declare readOnlyHint=true and openWorldHint=false, and the description is consistent with a pure calculation. It adds real behavioral context beyond annotations: which items are mandatory, how they are priced by unit, that the skipper/extras are only added 'if the source lists a price', and explicitly what the total excludes (deposit, fuel, marinas, food). It stops short of discussing missing-price handling or how the figures are sourced for the total.

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?

It is one front-loaded sentence that leads with the core outcome ('what one boat-week really costs') and then enumerates components. It is dense and slightly overstuffed with parenthetical lists, but every clause adds substantive scope information, so there is little waste.

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 read-only annotations, a full output schema, and 100%-documented parameters, the description's job is mostly scope framing, which it does well by naming inclusions, per-unit pricing, totals, per-person output, and exclusions. The remaining gap is the lack of any routing guidance against the cost-adjacent siblings (prices_by_month, compare_boats).

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%, including examples for id/url and extras, so the schema carries parameter meaning. The description only echoes the skipper and extras concepts ('skipper and other optional extras on request') without adding format, defaults, or interaction rules beyond what the schema already states. Baseline 3 applies.

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?

The description states a concrete computation (boat price + mandatory extras + optional extras, priced by unit, total and per person) for a distinctly named resource: a boat-week. It is clearly not a generic price listing like prices_by_month or a comparison like compare_boats, so the agent can distinguish it from siblings on description 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?

Usage is implied: it is the tool for the 'real' cost of one boat-week, which suggests running it after finding a deal. However, it never states when to prefer it over prices_by_month, compare_boats, or is_good_deal, nor does it give prerequisites (e.g. that id or url should come from search_deals).

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