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

Annotations already declare readOnlyHint and openWorldHint=false, so safety is covered. The description adds genuinely non-obvious behavior: for country-level refs the response expands to include child regions that have guides, which an agent could not infer from the schema. It stops short of noting locale-dependent content fallback or behavior on an unknown path.

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?

Two sentences with no filler, and the core answer (what the guide contains) is front-loaded before the country-specific caveat. The second sentence requires a slight re-read to parse, but nothing is wasted.

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 simple read-only lookup with two fully documented parameters and no output schema, the description covers content scope, entity granularity, and the country-expansion behavior. The main remaining gap is that it does not describe the response shape or what happens for an unresolved ref, which matters somewhat since no output schema exists.

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 `ref` (path pattern, example values) and `locale` (enum, default, propagation rule) are fully documented in the schema. The description adds only the looser framing that a ref may be a country, region or appellation, which the schema examples already convey. 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?

Names the resource precisely (a guide to a wine-producing country, region or appellation) and enumerates the content returned: history, terroir, grapes, producers. This distinguishes it from get_grape, get_wine and get_producer, which return individual entities rather than a regional guide, though the description never explicitly contrasts itself with those siblings.

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 only implied: the tool takes a path-style ref, and the note 'For a country, also lists its regions that have a guide' hints at a browse/discovery use case. There is no explicit statement of when to call this versus get_wine or get_grape, and no stated prerequisite that the ref must originate from `search` (that detail lives only in the schema).

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