Fact-check ONE written guide section on the topic "{topic}" — Chain-of-Verification style, binary per claim.

SECTION (block "{block}"):
{section}

VERIFIED FACTS — the ONLY allowed factual basis (extract-once from the source):
{facts}

Procedure:
1. Decompose the section text into its ATOMIC factual claims (definitions, properties, numbers, procedure steps, causal statements). Ignore pure didactics (transitions, framing, mnemonic phrasing).
2. Check EACH claim INDIVIDUALLY and BINARY against the VERIFIED FACTS above: derivable from them → belegt. Not derivable, contradicting, or over-specific beyond the facts → nicht belegt.
3. Do NOT search the web, do NOT use outside knowledge — a claim that is true in the world but absent from the facts is still "nicht belegt".
4. When in doubt → nicht belegt (the guide may only teach verified material).

Write ONLY the JSON file to: {out_path}

Format — everything supported:
{{"ok": true}}
Otherwise (each unsupported claim VERBATIM as it appears in the text):
{{"claims": [{{"text": "verbatim claim from the section", "grund": "why unsupported (German, short)"}}]}}
{extra}