# `LangExtract.Prompt.Builder`
[🔗](https://github.com/mdepolli/lang_extract/blob/v0.10.0/lib/lang_extract/prompt/builder.ex#L1)

Renders Q&A-formatted prompts from a template for LLM extraction.

The framing mirrors upstream langextract's `QAPromptGenerator`: an
`Examples` heading, `Q:`/`A:` pairs (answers are code-fenced by
`WireFormat.format_extractions/1`), and a trailing bare `A:` that primes
the model to emit the artifact directly. Measured on the ner benchmark
(2026-07-05 probe series, benchmark/decisions/): this scaffold cuts output tokens
~20% versus bare concatenation by reducing adaptive-thinking spend, with
no alignment cost.

# `build`

```elixir
@spec build(LangExtract.Template.t(), String.t()) :: String.t()
```

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*Consult [api-reference.md](api-reference.md) for complete listing*