costs_by_provider

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

With no annotations provided, the description is responsible for behavioral disclosure. It mentions output metrics and sorting but omits key details such as that it is a read-only operation, how the time window (window_hours) affects results, or any limits/pagination.

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 front-loads the key information (what the tool returns and how it is sorted), with no superfluous content.

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 has one optional parameter, no output schema, and several siblings, the description fails to explain the parameter or provide usage guidance, making it incomplete despite adequately covering purpose and basic output.

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 has one parameter (window_hours) with 0% description coverage in the schema. The description does not mention window_hours at all, leaving the agent unaware of how to specify the time range for the breakdown.

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 it provides a per-provider cost breakdown with specific metrics (total spend, request count, token counts, share of total) sorted by cost descending, which distinguishes it from siblings like costs_by_agent and cost_overview.

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 implies the tool is for per-provider breakdowns but does not explicitly state when to use it over alternatives like costs_by_agent or cost_overview, nor does it provide exclusions or context for when it is appropriate.

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