create_expense

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

With no annotations provided, the description carries full responsibility for behavioral disclosure. It only states the action and parameter formats, but omits critical traits such as whether the operation is destructive, authorization requirements, idempotency, or side effects like triggering billing updates. This is insufficient for an agent to understand the tool's impact.

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 short and directly states the purpose followed by parameter hints. It avoids unnecessary words and is front-loaded. However, it could be better structured by listing parameters separately, but overall it is concise and efficient.

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 complexity (6 parameters, no schema descriptions, no annotations), the description is too sparse. It does not explain what an expense entry represents, the need for a matter context, or any constraints. The presence of an output schema reduces the need to describe return values, but the description still lacks essential context for correct usage.

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 0% description coverage, so the description must compensate. It explains three parameters (date format YYYY-MM-DD, amount as dollar value, billable as 'true'/'false' with default). However, it fails to describe the required matter_id and the optional description and activity_code_id, leaving a gap. The provided formats are helpful but incomplete.

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 'Create an expense entry', which explicitly identifies the action and resource. It provides format hints for date and amount, adding clarity beyond the name. However, it does not distinguish this tool from siblings like create_fee or create_transaction, but the resource name 'expense' is specific enough.

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 offers no guidance on when to use this tool versus alternatives such as create_fee or patch_expense. It does not mention prerequisites like needing a matter_id, or scenarios where this tool is appropriate. The absence of usage context leaves the agent without decision support.

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