The failure is caused by an underspecified extraction policy rather than an inadequate JSON structure. “Extract all skills mentioned” does not define whether coordinated phrases should be split, whether inferred capabilities qualify, or what level of specificity constitutes one skill. Few-shot examples can demonstrate all three decisions using concrete inputs and expected outputs.

Anthropic identifies examples as one of the most effective ways to improve output accuracy and consistency because they communicate behavior more precisely than abstract instructions alone. Representative examples can show that “Python and SQL” becomes two entries, that an unstated skill must not be inferred from a job title, and that broad descriptions should not be decomposed into dozens of speculative micro-skills. ( https://docs.anthropic.com/en/docs/about-claude/use-case-guides/ticket-routing )

Option A adds provenance and confidence metadata but does not define the correct extraction granularity. Option C addresses explicitness and splitting, but the arbitrary 10–20 limit can truncate documents containing more than 20 legitimate skills or force padding when fewer than 10 appear. Option D is useful for canonicalization and deduplication, but post-processing cannot reliably remove plausible implied skills or determine how the original phrase should have been interpreted.

The strongest prompt should combine explicit rules with diverse few-shot examples covering normal cases, compound phrases, implied information, duplicates, and unusually long or short skill lists.

Official references/topics: Few-Shot Prompting, Output Consistency, Explicit Extraction Criteria, Representative Examples.