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

With only openWorldHint in the annotations, the description carries the burden and does so: it discloses the 25 MB size limit, that pages are measured the same way the order form measures an upload (a billing implication), and that the returned file_token is valid for 24 hours and a single order. Those are exactly the non-obvious constraints an agent needs before committing a customer to a paid translation.

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?

Three sentences, each doing distinct work — inputs, downstream contract, fallback — in a sensible order with no filler. The sentences are long and clause-heavy (the first especially), which costs a little readability, but nothing is redundant with the schema or annotations.

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?

There is no output schema, yet the description still tells the agent what comes back (billable pages and a file_token) plus its lifetime, and it covers the failure path when no input mode is available. For a 4-parameter tool with a nested attachment object, nothing an agent needs to invoke 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 already 100%, so the baseline is 3; the description adds selection semantics beyond the schema by framing the three modes as mutually exclusive choices tied to where the agent holds the file. It does not add format or validation detail beyond what the schema's own field descriptions provide, so it sits just above baseline rather than at the top.

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 opens with a specific verb and resource ('Sends a document to be translated') and immediately enumerates the three accepted input forms with concrete formats (PDF, image or Office file, up to 25 MB). It clearly positions the tool ahead of get_quote/create_order in the workflow by explaining the file_token handoff, so an agent can distinguish it from every sibling without opening a 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?

It states which input to use in which situation: `document` for chat attachments, `url` for public https links, `content_base64` plus filename 'when you hold the bytes yourself'. It also names an explicit fallback path — create the order from the customer's page count and let them upload at status_url after paying — so the agent knows both when to use this tool and what to do when it cannot be used.

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