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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuinely new context beyond the structured fields — that the boundary comes back as a GeoJSON Polygon — which is behaviorally relevant given no output schema exists.

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 short sentences, zero waste, and the core purpose is front-loaded ahead of the return-format note. Both sentences earn their place for a simple lookup tool.

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-parameter read tool with no output schema, the description supplies the key payload detail (GeoJSON Polygon boundary) that an agent would otherwise have to discover at call time. It doesn't describe error behavior for an unknown ID, which is a minor remaining gap.

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 single 'id' parameter is already fully documented as a UUID in the schema, so the description's 'by ID' adds no format or constraint detail. Baseline 3 is correct when the schema carries the full parameter burden.

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+resource ('Get a single infrastructure zone by ID') and signals single-record retrieval, which implicitly contrasts with the sibling list_infrastructure_zones. It never names that sibling explicitly, so an agent must infer the distinction, but the scope word 'single' does meaningful routing work.

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?

The 'single ... by ID' phrasing implies the usage context (fetch one known zone rather than enumerate or mutate), but no explicit when/when-not guidance or named alternative is given. Adequate but leaves the agent to infer that list_infrastructure_zones is the bulk alternative.

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