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

Despite annotations already declaring non-destructive/non-open-world behavior, the description adds substantial context beyond them: it returns a receipt and never the figures, the balance sheet sheet discloses what it cannot see, a conditional Loans sheet appears based on loan data or unreadable loans, and the receipt enumerates the sheets. These are real behavioral traits an agent needs to interpret the call outcome.

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?

It is front-loaded with the core purpose before the usage rule, and most sentences carry distinct information (receipt behavior, conditional sheets, loan contents). It is somewhat long and has a few loosely packed clauses ('the same as the tool does', 'and then the receipt's note says so'), but for a tool with this many conditional outcomes the length is largely earned.

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 an output schema exists, the description needn't explain return values, yet it does clarify the receipt's role and the conditional sheet structure. Combined with the 100%-covered input schema, an agent has everything needed to call it and interpret the result.

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 schema already documents all four parameters including the compare-from/compare-to pairing rule. The description only mentions 'for a period' and adds no syntax, defaults, or format guidance beyond the schema, so the baseline 3 applies.

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 verb and resource — writing the household's income/expenditure statement and balance sheet to one Excel file with a sheet each — and explicitly distinguishes itself from the conversational siblings income_and_expenditure and balance_sheet. An agent can tell exactly what it produces and when it differs from the report tools.

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?

It names the alternatives (income_and_expenditure, balance_sheet) and the exact condition that selects this tool: when the answer is 'give me the file' rather than a conversational figure. That is an explicit when/when-not routing rule, not an implication.

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