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

Annotations cover the safety profile (readOnly, idempotent, openWorld, non-destructive), and the description goes well beyond them: it discloses the paid x402 flow, the required PAYMENT-SIGNATURE header, the $0.04 USDC cost on Base, ~25 ms payment challenge latency and ~1.5 s average processing. These are behavioral traits an agent cannot get from the annotations.

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?

Purpose is front-loaded in the first clause, which is good, but the remaining sentences are repetitive marketing/payment detail: 'Pay-per-call over x402 in USDC on Base' and 'Costs $0.04 USDC per call (x402 v2, Base)' state the same fact twice. It is denser than it needs to be for a 3-parameter tool.

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 ideally state the return shape (translated string), which it does not. However, for this complexity level it covers the critical operational facts an agent needs — endpoint, auth header, cost, and latency — so it is close to 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 description coverage is 0%, so the description must carry parameter meaning. It identifies the language pair (fr/en, matching the target enum) and calls tone optional, but never enumerates the tone values or notes the 1–40,000 character bounds on text, so it only partially compensates.

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?

Names the specific verb (translate), the resource (text), and the scope (French including Quebec French ↔ English) with the optional tone modifier. Nothing about this overlaps with siblings like extract, summarize, or pkg_check, so the agent can route to it unambiguously.

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 implies when the tool applies (text translation between FR/EN) but never states when to prefer it or what to do instead when the text is already in the target language or too long. It offers payment mechanics rather than usage guidance or exclusions.

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