Fetch a single expense's details by providing its unique ID, enabling quick retrieval of stored transaction data for review or verification.
Fetch a single expense entry by id.
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | ID of the expense to fetch. |
| 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?
No annotations are provided, so the description carries the full behavioral burden. 'Fetch' clearly marks it as a read operation, but it does not disclose error behavior, authentication needs, rate limits, or any explicit side-effect guarantees beyond what the verb implies.
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 a single, front-loaded sentence with zero filler. It communicates the essential operation and the key parameter in eight words.
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 one-parameter read operation that has an output schema, the description is complete enough. The agent knows the tool fetches one expense by id, and the schema and output schema cover the remaining details needed for correct invocation.
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 coverage is 100% and the schema already describes id as 'ID of the expense to fetch.' The description's 'by id' adds no new meaning beyond the schema's parameter documentation.
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 the specific verb 'Fetch' plus the resource 'single expense entry' and the key discriminator 'by id.' This makes the tool's purpose unmistakable and distinguishes it from list_expenses and the other sibling operations.
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 retrieving one specific expense by id, but it never explicitly mentions when to use it instead of list_expenses or any exclusions. It relies on the sibling names to convey usage context rather than stating it directly.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.