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

Annotations already declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false, but the description adds material behavior beyond them: the country is immutable once set, clearing the storefront address is not reversible without re-entry, and the two-call preview/confirm cycle is mandatory. It also explains the safety model ('saving the same list again is safe') in operational terms rather than just echoing the idempotency hint.

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 action is front-loaded in the first sentence, and the subsequent sentences each carry operational constraints (list size, business_type, region_code, storefront clearing, preview flow). It is dense and largely waste-free, though a couple of clauses restate schema-level details.

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 10-parameter mutation tool with no output schema, the description covers the mutation semantics, prerequisite data sources, immutability constraints, and the preview/confirm workflow, which is enough to call it correctly. It doesn't cover preview expiry or what the preview payload contains, a minor gap given 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 coverage is 90%, so the baseline is 3, but the description adds value the schema does not: the 1-to-20 places list must come from list_google_business_service_areas view=places or a known region Place ID, and it reinforces the consequences of region_code and clear_storefront_address. Much of the remaining text overlaps the schema, so it does not fully exceed the baseline.

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 opening sentence states a precise verb and resource: replacing the service-area list on a Google Business location. It is immediately distinguishable from the sibling list_google_business_service_areas, which it explicitly names as the source of place IDs. An agent knows exactly what mutation this performs.

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 gives concrete conditions for parameters: business_type selection semantics, when region_code is required, and when clear_storefront_address must be set. It also spells out the preview-then-confirm protocol and points to list_google_business_service_areas for place IDs. It stops short of explicitly stating when not to use this tool versus manage_google_business_location, so it is clear context rather than full routing.

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