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

Annotations already cover the safety profile (readOnly, non-destructive, closed-world). The description adds materially important behavior the annotations don't: a $0.02 USDC charge on Base via x402 and the underlying REST route POST /v1/translate/check. It doesn't describe failure modes or what happens if payment is declined, keeping it below a 5.

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?

Two sentences, both dense in information: the first front-loads the use case and output, the second carries cost and transport. No filler, and the most decision-relevant content comes first.

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 2-parameter scoring tool with no output schema, the description covers purpose, evaluation dimensions, the 0-100 return range, and the payment/transport model an agent must know before calling. A brief note on response shape beyond the score would make it fully 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 both parameters are already documented, and the baseline is 3. The description adds the evaluation criteria the two texts are judged against, which gives useful context, but it doesn't clarify parameter-level semantics (e.g., direction detection, length limits) beyond what the schema states.

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 names a specific verb+resource (EN<->FA translation QA score, 0-100) and enumerates the criteria checked: numbers/entities preserved, script purity, untranslated segments. It does not differentiate itself from siblings like text_analyze or hook_score, but the tool's identity 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?

"Use this when you need an EN<->FA translation QA score" gives an explicit trigger condition. It doesn't name when NOT to use it or point to a sibling alternative such as text_analyze for general text checks, so it stops short of full routing guidance.

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