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

The annotations already state readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds that the returned expense includes its lines, which is useful behavioral context, but it does not mention not-found behavior, permissions, or response shape beyond that.

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 entire description is two short fragments, front-loaded with what the tool returns and followed by the endpoint. There is no filler.

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 single-record read tool with one fully documented parameter and read-only annotations, the definition is largely complete. It even indicates that the expense's lines are included, though it could say more about the returned object given there is no output schema.

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%, and the sole 'id' parameter is fully documented as 'Expense id.' in the schema. The description only echoes the id through the endpoint path and adds no syntax or format details 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?

The description states a specific resource ('expense') and scope ('one expense with its lines'), and the endpoint makes the singular retrieval unambiguous. It doesn't explicitly name the sibling list tool, but the singular/plural contrast is easy to infer from 'One expense' versus 'jurnal_list_expenses'.

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 endpoint and required id imply that this is for fetching a single known expense, but there is no explicit when-to-use guidance, no mention of when not to use it, and no direct alternative such as the list tool.

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