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

Annotations only declare readOnlyHint and openWorldHint; the description adds substantial context beyond them: the 6,000-character cap, the guarantee that formatting, names, numbers and URLs survive translation, automatic language detection, and a paid-call model ($0.002 USDC via x402 on Base, Solana or Arc) with failed calls not charged. The payment/auth and billing-failure behavior is exactly the kind of disclosure an agent needs before invoking a metered tool.

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?

Information is front-loaded: capability and limits first, sibling routing next, pricing last. Every clause carries real information, though the single dense paragraph packs limits, behavior guarantees, routing and billing together, which slightly hurts scannability.

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, return values need no explanation, and the description still covers the remaining gaps an agent would have: size limit, language input forms, auto-detection, fidelity guarantees, sibling disambiguation, and cost/payment mechanism. Nothing material needed to call it correctly is missing.

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 all three parameters are already documented in the input schema, making 3 the baseline. The description adds only a small amount beyond that by enumerating example language codes (en, tr, de, fr, es, ar, zh) and noting both codes and names are accepted. The character limit it cites merely restates the text parameter's schema description.

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 and resource ('Translation with Llama 3.1 8B') plus concrete scope: 6,000 characters per call, preservation of formatting/names/numbers/URLs, and automatic source-language detection. It also explicitly distinguishes itself from the nearest sibling, translate_subtitles, so an agent can route without opening either schema.

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?

Gives explicit routing guidance for the closest alternative: use translate_subtitles when converting an SRT or WebVTT file. It also tells the agent source language is optional because it is auto-detected. It does not address other potentially overlapping siblings such as text_paraphrase or text_transliterate, so it falls short of full when/when-not coverage.

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