Update Expense

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

Annotations already declare idempotentHint=true and destructiveHint=false. The description adds 'PATCH semantics' and 'only provided fields will be changed', which is consistent but adds minimal extra behavioral context beyond what annotations provide.

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, includes a concrete example, and is front-loaded with the key purpose and semantics. Every word contributes, and the bilingual aspect is necessary for the audience.

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?

Given the presence of an output schema and full parameter descriptions, the description is sufficiently complete. It covers the core behavior and includes an example, though it does not mention prerequisites or failure scenarios.

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%, so the input schema already describes all parameters. The description provides an example (id, amount, category) but adds no additional semantic 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?

The description clearly states 'Update an existing expense using PATCH semantics', specifying the verb (update), resource (expense), and behavior (partial update). This distinguishes it from siblings like create_expense, delete_expense, and get_expense.

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 explicitly notes that only provided fields are changed, implying use for partial modifications. It does not directly contrast with alternatives, but the context of sibling tools makes it clear this is for updating specific fields rather than replacing the whole resource.

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