Create Expense

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

With no annotations provided, the description carries the full behavioral disclosure burden. It discloses meaningful behaviors: cost must be a string with 2 decimals, equal splitting is the default, custom split requires paid_share/owed_share, and user identity must be user_id or a full email/first/last combination. These details go beyond the schema and clarify how the API behaves.

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 concise and well-structured. It front-loads the core purpose, then gives the most important behavioral requirements in three additional dense sentences. Every sentence contributes necessary information without fluff or repetition.

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?

Given the tool's complexity (10 parameters, no annotations) the description covers the most error-prone areas: cost format, custom split inputs, user identity, and recurrence values. An output schema exists, so return value details are not required. It is nearly complete for a typical agent invocation, though it does not clarify how it differs from create_itemized_expense or explain the group_id default behavior.

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 description coverage is 0%, so the description must compensate. It adds essential semantics for cost formatting, the structure of the users array, and valid repeat_interval values. Some parameters like date, currency_code, group_id, and category_id are not explained in the description, though their names are fairly self-explanatory in 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 a specific action and resource: 'Create a new expense.' It adds meaningful context about cost formatting, splits, and recurrence, making the tool's purpose obvious. However, it does not distinguish itself from the sibling create_itemized_expense, so it misses full differentiation.

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 conditional usage guidance: use custom splits when paid_share/owed_share are provided, and set repeat_interval for recurring expenses. It does not explicitly state when to prefer this tool over create_itemized_expense or other sibling tools, and it offers no exclusion criteria. This is better than no guidance, but not fully explicit.

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