get_billing_usage_by_datacenter

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

No annotations, so description carries full burden. Mentions default exclusion of zero-quantity meters and how to override. Also references FOCUS v1.3 compliant output. However, does not discuss permissions, error cases, or side effects.

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 plus a note on FOCUS. Efficient, no redundant information. Every sentence adds value.

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?

No output schema provided, but description does not explain return value structure or fields. For a tool that returns usage data, this is a notable gap. Otherwise, the description covers usage context adequately.

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%, so baseline is 3. Description adds context for contract (from get_billing_profile) and include_zero (default false, FOCUS reference), but adds little beyond schema descriptions.

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?

Clearly states 'Get aggregated resource usage for a specific datacenter (VDC UUID) in the current billing period.' Identifies verb, resource, and scope. Distinguishes from siblings by mentioning datacenter ID and referencing list_billing_usage.

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?

Explicitly advises 'Use list_billing_usage first to find datacenter IDs.' Also explains default behavior for include_zero. Provides clear context for when to use, though lacks explicit 'when not to use' alternatives.

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