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

Goes well beyond the annotations: discloses synchronous execution, automatic chunking at ~1,900 chars, credit cost (1 per call), gateway pre-charge behavior, and required Bearer auth on the endpoint. These are exactly the operational facts an agent needs and cannot get from readOnlyHint/openWorldHint alone.

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?

Six short, information-dense statements with limits and cost front-loaded ahead of operational details. No filler or restatement of the title.

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?

Covers scope, limits, cost, and auth thoroughly, which is most of what matters here. There is no output schema and the description never indicates the return shape (e.g., translated strings in input order), leaving a small gap for the agent.

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 the baseline is 3, but the description adds processing semantics the schema can't convey: how oversized `text` is chunked and that total length across `texts` is capped. It does not elaborate on language-code formats, though the schema examples already cover that.

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 ('translate ... plain text') and scopes it against its siblings implicitly by naming 'plain text' versus translate_document/translate_image/translate_subtitle. The input limits are stated up front, so an agent knows exactly what this call handles.

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 clear operating context: synchronous, size caps (50,000 chars / 50 strings), and automatic chunking for long inputs. It does not explicitly say 'use translate_document for files' or name an alternative, so routing versus siblings is left to inference from the 'plain text' framing.

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