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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=true), so the description's job is to add context, and it does: it states the return shape (calculated result plus complete equation in both Roman and integer formats) and discloses a per-call cost of 1 credit. It does not address edge behavior such as invalid numerals or how division handles non-integer results, which is the main remaining gap.

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?

Effectively two sentences that front-load the operation and then the return format, with the cost appended in parentheses. Minor waste in the 'Roman Numeral Math: Roman Numeral Math ...' prefix that restates the name verbatim.

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 an output schema present, the description needn't explain return values, yet it does so concisely, and it covers cost and operation set. For a low-complexity two-input tool this is nearly complete; only failure modes (malformed Roman numerals, division rounding) are unaddressed.

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 would be 3, but the description adds real value the schema omits: it enumerates the four supported operations, whereas the schema's 'operation' property has no enum and only an 'add' example. The roman1/roman2 semantics are fully covered by the schema and need no further explanation.

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 gives a specific verb ('computes addition, subtraction, multiplication, and division') and a specific resource ('between two Roman numerals'), which clearly separates it from pure conversion tools. It never names the closest sibling, RomanNumeralConverter, so an agent must infer the boundary rather than being told it.

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 implied by the arithmetic framing, but there is no explicit when-to-use or when-not-to-use guidance, and no pointer to RomanNumeralConverter for plain conversion or MathCalculator for integer math. The cost note ('1 credit') is helpful context but is not routing guidance.

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