ibmcloud_billing_resource_instances_usage

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

With no annotations provided, the description must disclose behavioral traits on its own. While 'get' implies a read-only operation, it doesn't mention authentication requirements, rate limits, possible pagination, or whether usage data is aggregated or itemized. The description is too thin to fully inform the agent about the tool's behavior.

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 description is a single, concise sentence that is front-loaded with the key action and resource. No wasted words or redundancy.

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 lookup tool with two clearly described optional parameters, the description is minimally sufficient. However, there is no output schema and no mention of what the returned usage data contains or how it might be filtered beyond the parameters. The lack of guidance on differentiating from sibling billing tools leaves a slight gap, but the tool is simple enough that this is not a major deficiency.

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?

The input schema already provides full descriptions for both parameters (month and resource_group), so schema coverage is 100%. The description adds no extra meaning about how these parameters interact or what the output looks like. This matches the baseline of 3 for complete schema coverage.

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 'Get usage for resource instances' clearly states a specific verb and resource: it fetches usage data for resource instances. It is distinct from sibling tools like billing_account_usage or billing_resource_group_usage, as it targets resource instances specifically, though it doesn't explicitly call out those alternatives.

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 provides no guidance on when to use this tool versus alternatives such as ibmcloud_billing_account_usage or ibmcloud_billing_resource_group_usage. There is no mention of context, prerequisites, or exclusions. The only implicit signal is the resource scope in the name, but the description itself is silent on usage context.

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