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

Annotations already establish readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. Beyond that the description usefully adds that rounding is always upward and that VAT is optional rather than required, but it says nothing about what exactly is returned (pre-VAT vs VAT-inclusive figures) or about the margin<100 boundary.

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-loaded with the core operation, single logical sentence per language, no filler. The full Vietnamese/English duplication roughly doubles the length, which is defensible for a bilingual tool but does cost some economy.

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?

With no output schema, the description should clarify what the tool returns, and it only hints that a VAT-inclusive price accompanies the base price. For a five-parameter calculation tool with two output variants, that leaves the agent guessing about the response shape.

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 100%, so the schema already documents every parameter, including the margin/markup enum meaning, the round_to default of 1.000 đ, and the allowed VAT rates. The description adds only the VND currency context and does not elaborate on round_to or vat_rate beyond the 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?

States a specific verb+resource: compute selling price from unit cost, with the two calculation methods (margin/markup), rounding up, and optional VAT in VND. It clearly distinguishes itself from calculate_vat (which only computes tax) by framing VAT as an optional add-on, though siblings build_quote and simulate_referral_commission are not addressed.

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?

Usage is only implied by the purpose statement — there is no explicit when-to-use or when-not-to-use guidance, and no routing to calculate_vat or build_quote even though both overlap with pricing/tax work.

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