Add Expense

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

With no annotations, the description carries the full transparency burden. It clearly indicates the mutating behavior ('Add a new expense') and adds a significant constraint about category/subcategory sourcing. However, it does not mention validation failure behavior, permissions, reversibility, or other side effects beyond the act of adding.

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 three sentences with no filler: the first states the action, and the next two deliver the key sourcing constraints. It is front-loaded and every sentence earns its place.

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 create tool with an output schema, the description covers the most non-obvious aspect (category/subcategory sourcing) but omits date and amount expectations and gives no sibling-tool routing. It is adequate but leaves clear gaps an agent must resolve elsewhere.

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 meaningful semantics for category and subcategory, including the empty-subcategory rule, but it provides no guidance on date format, amount constraints, or note semantics, leaving some required parameters underspecified.

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 opens with 'Add a new expense,' a specific verb-resource pair that clearly identifies the tool's function. It also differentiates it from siblings like add_credit and the expense list/update/delete tools by naming the resource type.

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 provides useful input-level guidance, especially that category and subcategory must come from data://categories, but it does not explicitly say when to prefer add_expense over alternatives like add_credit, nor does it state exclusions or when not to use the tool.

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