TASK: Generate Chapter Sections Structure

LANGUAGE: Generate all content in DE language. All text, titles, headings, paragraphs, and content must be written in DE.

CHAPTER: Einleitung (Level 1, ID: chapter_1)
GENERATION HINT: Einleitung der E-Mail, die den Zweck und den Kontext der Nachricht kurz beschreibt.

## CONTENT EFFICIENCY PRINCIPLES
- Generate COMPACT sections: Focus on essential information only
- AVOID creating too many sections - combine related content where possible
- Each section should serve a clear purpose with meaningful data
- If no relevant data exists for a topic, do NOT create a section for it
- Prefer ONE comprehensive section over multiple sparse sections
- HARD LIMIT: Maximum 5 sections per chapter. Combine related subtopics into single sections to stay within this limit.

**CRITICAL**: The chapter's generationHint above describes what content this chapter should generate. If the generationHint references documents/images/data, then EACH section that generates content for this chapter MUST assign the relevant ContentParts from AVAILABLE CONTENT PARTS below.

NOTE: Chapter already has a heading section. Do NOT generate a heading for the chapter title.

## SECTION INDEPENDENCE
- Each section is independent and self-contained
- One section does NOT have information about another section
- Each section must provide its own context and be understandable alone

AVAILABLE CONTENT PARTS:

(No content parts specified for this chapter)

## CONTENT ASSIGNMENT RULE - CRITICAL
If AVAILABLE CONTENT PARTS are listed above, then EVERY section that generates content related to those ContentParts MUST assign them explicitly.

**Assignment logic:**
- If section generates text content ABOUT a ContentPart → assign "extracted" format ContentPart with appropriate instruction
- If section DISPLAYS a ContentPart → assign "object" format ContentPart
- If section's generationHint or purpose relates to a ContentPart listed above → it MUST have contentPartIds assigned
- If chapter's generationHint references documents/images/data AND section generates content for that chapter → section MUST assign relevant ContentParts
- Empty contentPartIds [] are only allowed if section generates content WITHOUT referencing any available ContentParts AND WITHOUT relating to chapter's generationHint

## ACCEPTED CONTENT TYPES FOR THIS FORMAT
The document output format (txt) accepts only the following content types:
table, bullet_list, heading, paragraph, code_block

**CRITICAL**: Only create sections with content types from this list. Other types will fail.

useAiCall RULE (simple):
- useAiCall: true → Content needs AI processing (extract, transform, generate, filter, summarize)
- useAiCall: false → Content can be inserted directly without changes (Format is "object" or "reference")

RETURN JSON:
{
  "sections": [
    {
      "id": "section_1",
      "content_type": "table",
      "contentPartIds": ["extracted_part_id"],
      "generationHint": "Description of what to extract or generate",
      "useAiCall": true,
      "elements": []
    }
  ]
}

**MANDATORY CONTENT ASSIGNMENT CHECK:**
For each section, verify:
1. Are ContentParts listed in AVAILABLE CONTENT PARTS above?
2. Does this section's generationHint or purpose relate to those ContentParts?
3. If YES to both → section MUST have contentPartIds assigned (cannot be empty [])
4. Assign ContentPart IDs exactly as listed in AVAILABLE CONTENT PARTS above

IMAGE SECTIONS:
- For image sections, always provide a "caption" field with a descriptive caption for the image.

Return only valid JSON. Do not include any explanatory text outside the JSON.