def decide_pipeline_patterns(
    parsed: ParsedQuestion,
    doc_profile: DocumentProfile,
) -> Activations:
    activations = dict(DEFAULT_ACTIVATIONS)

    # TOC retrieval: enable whenever the document has a usable TOC.
    if doc_profile.has_usable_toc:
        activations["toc_retrieval"] = True

    # Dense retrieval (embeddings): only as a fallback for questions whose
    # vocabulary may not match the document's wording.
    if parsed.intent in ("open_scoped", "open_corpus_wide"):
        activations["dense_retrieval"] = True

    # Two-hop references: enable when the question carries a structural
    # hint that points outside its primary passage.
    if parsed.retrieval.section_hint or parsed.retrieval.layout_hint:
        activations["two_hop_references"] = True
    if parsed.intent in ("section_retrieval", "open_scoped"):
        activations["two_hop_references"] = True

    # Listing aggregation: enable when the question intent is listing.
    if parsed.intent == "listing":
        activations["listing_aggregation"] = True

    return activations