calc_usn

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

With no annotations, the description carries full burden. It explicitly states the tool is 'read-only, offline', explains the calculation logic for both tax objects, minimum tax, contributions deduction, and that it subtracts advances_paid. It also lists return fields, providing full behavioral transparency.

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 well-structured with headings ('When to use', 'When NOT to use', 'Parameters', 'Returns', 'Limitations') and bullet points. It is concise yet comprehensive, with every sentence adding necessary information.

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 tool's complexity (7 params, two tax regimes, contributions deduction, minimum tax), the description covers all aspects: usage context, parameter explanation, return structure, and limitations. The existence of an output schema complements the description, but the description itself is highly complete.

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 baseline is 3. The description adds value by grouping parameters (e.g., 'Parameters: income, obj, expenses...') and explaining their role in context (e.g., 'contributions_paid: for object income'). It also notes rate is regional override, enhancing understanding beyond 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 'Calculate simplified tax (USN/УСН): 6% on income or 15% income-minus-expense with minimum tax'. It uses a specific verb and resource, and the description distinguishes it from sibling tools like calc_ndfl or calc_vat by specifying the tax type and regime. The limitations section further clarifies scope.

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 includes explicit 'When to use' and 'When NOT to use' sections, providing clear context. It advises to check get_rates for income limits, and lists exclusions like exact advance-payment calendar or KKT cash reporting. This helps the agent decide when to invoke this tool vs alternatives.

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