Cost report: by-biller

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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false. The description adds HTTP method (GET) and authorization class, but no further behavioral details (e.g., pagination, data freshness). Acceptable given annotation coverage.

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 overly terse, consisting of a title repetition and HTTP metadata. While concise, it sacrifices essential information that would aid tool selection and invocation.

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?

Despite having an output schema, the description does not mention what data the report returns, nor does it differentiate from sibling cost breakdown tools. Incomplete for an AI agent to understand its role.

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 description coverage is 0%, yet the description provides no explanation of the required 'companyId' parameter. It only appears in the path example without additional context, leaving the agent uninformed about its semantics.

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?

Title and description indicate 'Cost report: by-biller' and the HTTP path, vaguely suggesting retrieval of costs grouped by biller for a company. However, it does not clearly state the action (e.g., 'Retrieve cost breakdown by biller') and fails to distinguish from sibling cost tools.

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?

No guidance on when to use this tool versus alternatives like cost by agent, provider, or project. With many cost report siblings, the description offers no context for selection.

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