add_expense

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

No annotations are provided, so the description carries the full behavioral burden. It never states whether the expense is persisted immediately or synced via sync_data, whether it requires authentication, how duplicate entries are handled, or what happens on invalid account/category values.

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?

Two tight sentences with the core action and required inputs front-loaded; no filler. It could be marginally tighter by consolidating the two sentences, but it is efficiently sized.

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 six-parameter mutation tool with 100% schema coverage and no output schema, the description covers inputs adequately but omits return behavior (e.g., created transaction id) and side effects. Adequate minimum viable, but incomplete for a write operation with zero annotation coverage.

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 100%, so all six parameters are already documented in the schema, including the required set and the positive-amount constraint. The description merely restates required vs optional fields, adding no format or constraint detail beyond 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?

States a specific verb+resource (add an expense transaction) with the target system named, ZenMoney. The word 'expense' inherently separates it from sibling tools add_income and add_transfer, though it never names them explicitly.

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 lists required vs optional parameters but gives no when-to-use guidance, no condition distinguishing it from add_income or add_transfer, and no prerequisite steps (e.g., whether list_accounts/list_categories must be called first to obtain valid ids).

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