The Ledgerline team runs a document extraction service that asks the model to return supplier name, invoice number, invoice date and total as a JSON object, then validates that object against a JSON schema before it reaches the accounts payable system. Parse failures sat at 4 percent. An engineer adds three worked examples to the prompt, each pairing a short invoice with the exactly formatted JSON object it should produce, and parse failures fall to 0.6 percent across the next 20,000 documents. The architect has to record what the example set now guarantees about output structure. Which statement is correct?
- AThe examples raise the probability of the demonstrated shape without bounding it, so schema validation remains the only stage in the pipeline where a malformed object is actually rejected before the downstream system sees it. Correct
- BThe examples make the output shape deterministic for any document resembling the three worked cases, so schema validation is now redundant for that class of document and can be relaxed to a sampled check.
- CThe examples constrain decoding to the demonstrated shape, so a malformed object can now arise only from an illegible source document rather than from the generation step itself.
- DThe examples have no bearing on structure, and the fall in parse failures is attributable to the schema validation stage rejecting malformed objects and re-requesting them from the model.
Why A is correct: Correct: few-shot demonstration shifts the output distribution towards the shown format, which is why the rate fell, while the deterministic guarantee still comes from validating the produced object and refusing it on failure.
Why B is wrong: Tempting because the measured improvement is large and consistent, but a demonstrated shape is still produced by sampling, so a lower failure rate is not a bound, and relaxing validation removes the one stage that actually rejects a malformed object.
Why C is wrong: Plausible because few-shot examples do strongly influence formatting, but examples are conditioning rather than a decoding constraint, so the generation step retains its own residual failure rate independently of document quality.
Why D is wrong: Tempting because validation genuinely does catch malformed output, but validation was already running before the change at a 4 percent failure rate, so it cannot explain an improvement that followed the addition of the examples.