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

With readOnlyHint/idempotent/non-destructive already in annotations, the safety profile is covered, and the description layers on real domain behavior: exactly which contributions are computed and which are waived for pensioners, pre-1975 births and disabilities. It does not describe the return shape or the MZP-cap behavior at the edges, but the contribution logic is substantial added context.

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?

Front-loads trilingual keywords for discoverability, then a substantive sentence on scope and outputs, then the imperative about the required input. Every sentence carries weight; the trilingual header is slightly redundant against the name but justified for search recall.

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 an 8-parameter calculator with full schema coverage and no output schema, the description supplies the scope, the computed outputs, the exemption rules and the required user input. Only the response format and cap/limit edge cases remain unstated, which the absence of an output schema makes less critical.

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 baseline is 3, but the description adds genuine meaning beyond the schema: monthly declared income is required and sets the contribution base, and the exemption booleans are framed as a conditional ruleset. It reinforces value rather than merely restating fields.

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?

States a specific verb (calculates) plus concrete outputs — the half-year tax and the four mandatory monthly payments (OPV, OPVR, SO, VOSMS) — for a narrowly defined subject (ИП without employees, form 910.00, 2026). This is clearly distinguishable from every listed sibling, which cover salaries, maternity, mortgage, fines and indicators rather than IP tax.

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 scopes usage tightly: individual entrepreneurs without employees on the simplified declaration, 2026. It also tells the agent to elicit a required input before calling. It stops short of naming when NOT to use it or pointing to a related tool for the employed/other-regime case, so no explicit alternative is offered.

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