update_bill_run

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

No annotations provided, so description carries full burden. It discloses that the tool only works on pending bill runs, which is important. However, it does not mention side effects, idempotency, return value, or authorizations. For a mutation tool with no annotations, this is adequate but not comprehensive.

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?

Four sentences, each with a clear purpose: action, required params, format, and constraint. No redundancy or unnecessary text. The critical constraint is front-loaded in the last sentence but still effective.

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 all essential aspects: purpose, required parameters, format, and a key constraint. No output schema, so return values are not explained, but for a simple update tool it is sufficient. Lacks mention of what happens on success or error.

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 already covers parameters with 100% description, but the description adds useful ISO 8601 format details and timezone handling rules, enhancing beyond the schema's basic 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?

The description clearly states the tool updates a bill run, with the HTTP method and path. It distinguishes from siblings by specifying it works only on pending status, which is unique among bill run 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?

Explicitly states the tool only works on bill runs with status pending, and that calls on completed or error runs will fail. Provides ISO 8601 format guidance with timezone handling, giving clear context for when to use.

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