Update Expense

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

With no annotations, the description carries the full burden. It does disclose that only provided fields are changed (partial update), which is valuable. However, it doesn't mention side effects, like whether the update is idempotent or if missing fields are reset to defaults, which the schema defaults might imply. It also doesn't describe error behavior or authentication needs, but that may be out of scope.

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 two sentences with no fluff. It front-loads the main purpose and immediately clarifies the partial update behavior and the constraint. Every word earns its place.

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?

The tool has 6 parameters and an output schema, but no annotations. The description covers the partial update and one constraint, but lacks details on the effect of default values when fields are omitted (e.g., does omitting 'date' reset it to empty string?), which is crucial for correct usage. It also doesn't mention the output format, but the output schema exists, so that's covered. The main gap is parameter behavior nuances.

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, but it only mentions the category/subcategory constraint. It doesn't explain the id parameter beyond being required, nor the semantics of date, note, amount, or the null allowed for amount. However, the schema itself provides type and default information, which helps. The description adds a critical constraint for category/subcategory, giving some value.

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 it updates an existing expense, which is a specific verb and resource. It partially distinguishes from siblings like add_expense and delete_expense, but not explicitly. The mention of partial update (only provided fields) adds important behavioral nuance.

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?

It doesn't explicitly say when to use this tool versus alternatives, but the description implies it is for modifying existing expenses, which differentiates from adding or deleting. The constraint on category and subcategory from data://categories is useful but not a full usage guideline. It lacks exclusions or conditions for when not to use it.

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