Anthropic Cookbook: long-document map-reduce summarizer (chunked summaries to coherent whole)

Also from the cookbook summarization guide. The 'reduce' step that combines per-chunk summaries (generated cheaply with Haiku) into one coherent, sectioned final summary (using Sonnet). Demonstrates a real map-reduce-over-LLM pattern.

{chunk_summaries}

1. Parties involved (sublessor, sublessee, original lessor)
2. Property details (address, description, permitted use)
3. Term and rent (start date, end date, monthly rent, security deposit)
4. Responsibilities (utilities, maintenance, repairs)
5. Consent and notices (landlord's consent, notice requirements)
6. Special provisions (furniture, parking, subletting restrictions)

Provide the summary in bullet points nested within the XML header for each section. For example:

If any information is not explicitly stated in the document, note it as "Not specified".

Summary:

</user>

Assistant prefill: `Here is the summary of the legal document: <summary>` (stop sequence: `</summary>`)

Source: https://github.com/anthropics/anthropic-cookbook/blob/main/capabilities/summarization/guide.ipynb