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

With no annotations and no output schema, the description carries the full burden, but it only says 'calculate tax.' It does not disclose whether the result is the tax amount or tax-inclusive total, what side effects (if any) exist, or how mode changes behavior. This is insufficient for a tool with four otherwise undefined parameters.

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 short and front-loaded with the action. The redundant 'Tax Calc:' prefix is minor waste, but overall the two sentences are compact and each conveys useful 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?

For a 4-parameter tool with no annotations, no output schema, and zero required parameters, the description is under-specified. It omits what the return value looks like, which parameters are actually mandatory, and what values mode accepts, making correct invocation guesswork.

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?

Although the schema has 100% coverage, the descriptions ('Mode to process', 'Rate to process') are placeholder-level and add no meaning. The prose adds the useful fact that rate and taxRate are alternatives and that mode controls rate modes, but it never defines allowed mode values, input formats, or units.

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 clear verb and resource: 'Calculate tax on an amount.' It also introduces the key inputs (amount, rate/taxRate, mode). It does not explicitly differentiate from sibling tax-related tools, and 'Tax Calc' is redundant with the name, but the core purpose is unambiguous.

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 gives useful invocation guidance by saying to provide amount and rate (or taxRate) and that mode selects rate modes. However, it never states when to prefer this tool over alternatives or which parameters are actually required, leaving the selection and required-input logic to inference.

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