open_bill

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

No annotations are provided, so the description carries the burden. It states 'Reads' (indicating a non-destructive operation) and mentions the return format as a JSON list of products. However, it doesn't disclose error handling, authorization needs, or behavior for nonexistent invoice numbers.

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 brief and well-structured with a purpose statement, Args, and Returns. Every sentence provides useful information without redundancy, making it easy to scan.

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?

For a simple one-parameter read tool, the description covers the purpose, parameter, and return value. It lacks explicit handling of edge cases like missing invoices or empty results, but the tool's simplicity makes it reasonably complete.

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 schema has no description for invoice_no, but the description compensates by explaining it as 'The Invoice No of the bill.' This adds meaning beyond the schema's bare parameter definition.

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 states 'Reads the products inside a bill with the provided invoice_no,' which specifies a clear verb, resource, and scope. It distinguishes itself from siblings like fetch_bill_records (which fetches bill records) and add_item_to_bill (which modifies bills).

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 usage when one needs to read products from a bill, but it does not explicitly mention when to prefer this over alternatives or when not to use it. There are no exclusions or alternative tool references.

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