Update an existing expense by modifying only the fields you specify—amount, category, date, note, or subcategory. Provide the expense ID to target the record and keep other details unchanged.
Update only the provided fields of an existing expense.
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | ||
| date | No | ||
| note | No | ||
| amount | No | ||
| category | No | ||
| subcategory | No |
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the behavioral disclosure burden. It usefully reveals the patach semantics: omitted fields remain unchanged. However, it does not address what happens with null values, invalid ids, idempotency, or side effects. The main behavioral trait is disclosed, but richer context is missing.
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?
One sentence, no wasted words, and the core behavior is front-loaded. The description is appropriately sized for the tool's simple patch semantics.
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 description is minimally viable for an update tool: it states the operation, the resource, and the patach semantics, and the output schema handles return-value concerns. But with no annotations and no per-parameter descriptions, an agent still faces ambiguity around null vs omitted fields and how to handle non-existent expenses. It is adequate but noticeably incomplete.
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 the useful fact that only provided fields are updated, but it does not explain the six parameters individually, the role of the required id, or the distinction between omitting a field and explicitly passing null. The gap is significant for a 6-parameter patch tool.
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 uses a specific verb ('Update') with a clear resource ('an existing expense') and narrows scope to partial updates ('only the provided fields'). This distinguishes it from sibling tools like add_expense, delete_expense, list_expenses, and search_expenses, even though those alternatives are not named.
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 implies the tool is for modifying an existing expense rather than creating, deleting, or reading one, but it does not explicitly state when to prefer it over a sibling or give exclusions. The context is decipherable from the resource and operation, but the guidance is only implied, not explicit.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.