update_geographic_access_custom_region

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

Annotations already establish the safety profile (readOnlyHint=false, destructveHint=true), so the bar is lower. The description adds genuinely useful context beyond annotations: the UsersManager permission requirement and the ownership scoping to the authenticated tenant. The phrase 'Manage country-based access to tenants' hints at the broader side effects implied by openWorldHint=true, though it does not detail what destructive consequences may occur when countries are removed.

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 short sentences, each earning its place: domain context, primary function, and permission prerequisite. The main action is front-loaded in the second sentence. The first sentence is slightly broad ('Manage...') but adds useful business-domain framing, so the structure remains tight with no redundant filler.

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 5-parameter mutation tool with no output schema and destructiveHint=true, the description covers the essentials: what is updated, ownership, and permission. But it leaves meaningful gaps — whether updating one field preserves the other (partial update vs full replace), the role of the X-Tenant-Id header, and what destructive side effects (e.g., revoking tenant access) may occur. These gaps matter for an agent deciding how to invoke the tool correctly.

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?

With schema description coverage at only 20%, the description must compensate. It does partially: 'name, country membership, or both' maps meaningfully to the name and countryCodes fields, telling the agent these are the updatable properties — value the bare schema types do not provide. However, X-Tenant-Id is left undocumented by both schema and description, and customRegionId's role is only implied rather than stated, so compensation is incomplete.

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 specific verb and resource: 'Updates the name, country membership, or both for a custom region.' The opening phrase 'Manage country-based access to tenants in your customer hierarchy' gives valuable domain context. It distinguishes from sibling tools like get/delete/create_geographic_access_custom_region and the customer/user scope tools by specifying exactly which entity is being modified.

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 description gives clear context for when to use this tool: when an existing custom region's name or country membership needs modification. It also states the prerequisite ('Requires the UsersManager permission') and an ownership constraint ('owned by the authenticated tenant'), which helps an agent avoid misuse. However, it does not explicitly name alternatives or state when-not-to-use (e.g., use create_geographic_access_custom_region for new regions), so it falls short of a 5.

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