edit_bill_item_quantity

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

With no annotations, the description must disclose behavior. It states the update action, the unpaid/unissued condition, and the return format (confirmation or JSON error). However, it does not mention edge cases like non-existent items or whether the quantity is overwritten, leaving some behavioral ambiguity.

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 well-structured with a clear opening sentence, a labeled Args section, and a Returns section. It is somewhat longer than necessary but every sentence earns its place by providing required parameter details. It remains focused and readable.

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 update tool with no output schema, the description provides the action, parameter constraints, and return format. It does not explicitly list error scenarios, but the 'unpaid/unissued' condition covers a key prerequisite. The description is sufficiently complete for an agent to invoke the tool correctly.

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 provides only parameter names and types (all integers), but the description adds human-readable meaning for each parameter: 'invoice_no: Invoice Number', 'prod_id: a unique identifier', and 'quantity: quantity', along with validation rules like 'must be a positive value' and 'cannot be zero'. This fully compensates for the 0% schema description coverage.

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 opens with 'Updates the quantity of an existing unpaid/unissued bill item', which is a specific verb+resource+scope. This clearly distinguishes it from sibling tools like add_item_to_bill and delete_bill_item, which perform different operations on bill items.

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 specifies the tool applies to 'existing unpaid/unissued bill items', providing a clear context for when to use it. It does not explicitly name alternatives or exclusions, but the condition is sufficient for an agent to infer when this tool is appropriate.

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