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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint=false, so the safety profile is covered. The description adds real behavioral value beyond that: result shape per mode, that each entry carries a place count, and that each includes the address of its directory page.

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 tight, front-loaded sentences with no filler; the default-vs-filtered distinction is stated before the return detail. The opening phrase 'places where boats stayed the night' is slightly indirect but earns its place as domain framing.

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 single optional-parameter read tool with full schema coverage and an output schema, the description covers both call modes and what each result entry contains. Pagination or count freshness are unmentioned, but nothing essential for correct invocation is missing.

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 itself already explains the slug/ISO format and the 'every country when left out' default. The description restates this behavior without adding format examples or edge-case handling beyond the schema, so 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 names a concrete resource (the site's directory of places/countries/regions/cruising areas) and states what is returned in each mode. It is clearly a geographic directory listing, distinguishable from find_anchorages or get_climatology, though sibling differentiation is only implicit rather than stated.

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?

It explicitly describes the two call modes — omit `country` for the country list, supply it for regions/cruising areas — which gives practical guidance on parameterization. However, it never says when to prefer this tool over find_anchorages or get_bay_evidence, so tool-selection guidance is only implied.

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