sw_update_expense

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

With no annotations, the description carries full responsibility for behavioral disclosure. It clearly explains the dry-run preview behavior, that no network call occurs without confirm:true, and that the users array replaces the entire split. These are important, non-obvious behavioral traits that go beyond the basic purpose.

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 three sentences long, front-loaded with the core purpose, and each sentence delivers essential information without redundancy. It is well-structured and easy to parse.

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 tool with 10 parameters and no output schema, the description covers the key caveats (dry-run, full split replacement) and provides enough operational context. It could be more complete by mentioning the return value, but the description is adequate for most update scenarios.

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 50%, and the description adds some value by reiterating the full-replacement semantics of the users array and the confirm behavior. However, several parameters (date, details, category_id, description, currency_code) lack schema descriptions and are not explained in the description. The general instruction 'any fields to change' partially compensates, but not fully.

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 edits an existing Splitwise expense, using a specific verb and resource. It distinguishes from siblings like create or delete by focusing on updating existing expenses, and the purpose is immediately obvious.

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 clear context on when to use the tool: 'Provide expense_id and any fields to change.' It also includes crucial usage details about the full users array requirement and the dry-run vs confirm behavior. However, it does not explicitly state when not to use it or name alternative tools, though the sibling names make the alternatives apparent.

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