expense_add

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

Annotations indicate mutation (readOnlyHint=false) and non-destructiveness. The description adds that it returns a confirmation with details and an optional budget alert, but does not disclose other traits like duplicate handling or validation beyond the schema.

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 very concise: two sentences. The first sentence states the purpose, the second briefly describes Args and Returns. No wasted 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 simple creation tool, the description covers purpose, input shape, and return format. It lacks details like prerequisites (e.g., budget setup for alerts) but is otherwise adequate given schema richness.

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?

The schema has high internal coverage (descriptions for each property: amount, category, etc.). The description lists the parameters but adds no new semantics beyond summarizing them, so baseline 3 is appropriate.

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 'Save a new expense or income transaction' uses a specific verb 'Save' and clearly identifies the resource (expense/income transaction). It distinguishes this creation tool from sibling tools like expense_search, expense_delete, etc.

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 does not provide explicit when-to-use or when-not-to-use guidance. It implies its role as a creation tool relative to siblings, but lacks direct alternatives or exclusions.

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