billing_summary_all_accounts

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

With no annotations, the description must fully disclose behavior. It correctly implies a read-only, aggregate operation, but does not explain what 'summary' includes (e.g., per-account breakdown vs total), how the date range is interpreted, or any required permissions. It is minimally transparent but not misleading.

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 only two sentences, with the primary action front-loaded and no redundant wording. The second sentence adds a practical use case without unnecessary elaboration, making it efficient and appropriately sized.

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?

Given the tool's simplicity (one optional parameter, no output schema), the description is serviceable but incomplete. It lacks parameter-level details and explicit guidance on when to choose this over alternatives like billing_get_account_spend or insights_get_account_summary. It covers the basic purpose but not enough for fully informed selection and invocation.

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 0% and the description fails to mention the date_preset parameter by name. The phrase 'for a date range' hints at the parameter but provides no details on values, defaults, or formatting, leaving the agent without adequate guidance for a parameter that has no schema description.

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 clearly states the core function: 'Get a spend summary across ALL accessible ad accounts for a date range.' The verb 'Get' and the explicit scope of 'ALL accessible ad accounts' make the tool's purpose unmistakable and differentiate it from per-account billing tools like billing_get_account_spend.

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 sentence 'Useful for dashboards / quick agency-wide visibility' provides a clear use context. It implies this tool is intended for cross-account overview scenarios, which helps distinguish it from account-specific alternatives, though it does not explicitly name when not to use it.

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