update_bill_run

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

With no annotations, the description carries the full burden. It discloses the HTTP method, parameter constraints, and the pending status requirement. However, it omits important details like return value, side effects, and authentication requirements, leaving gaps in transparency.

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 clear but somewhat verbose, repeating information already in the schema (ISO 8601 format). It could be more concise while still conveying the key constraint about pending status.

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?

The description covers purpose, HTTP method, parameter constraints, and usage condition (pending status). However, it lacks information about return values or error scenarios, which is necessary given the absence of output schema and annotations.

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 the baseline is 3. The description adds minimal new information beyond what the schema already provides (e.g., timezone handling is redundant). It does not enhance understanding of parameter usage beyond the schema.

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 action ('Update a bill run') and resource, and includes the HTTP method and path. It distinguishes itself from sibling tools like update_invoice and update_customer by focusing specifically on bill runs.

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 a clear when-not condition: 'only works on bill runs with status pending. Calls against completed or error runs will fail.' It does not explicitly state when to use this tool versus alternatives, but given no other bill run update tools exist, the guidance is adequate.

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