diff --git a/backend-compliance/migrations/152_atom_classification.sql b/backend-compliance/migrations/152_atom_classification.sql
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+++ b/backend-compliance/migrations/152_atom_classification.sql
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+-- Migration 152: Atom-level topic classification (Haiku one-time pass)
+-- Pro atomarem Control x Use-Case: relevant? + Sub-Thema + kanonische Pflicht.
+-- Atom-grain Nachfolger des master-grain mc_use_case_mappings — die Master-
+-- Komposition (gpre2 object-only Clustering) ist als Topic-Einheit unbrauchbar
+-- (Mega-Cluster). Die Atome sind kohaerent; diese Tabelle traegt das Ergebnis
+-- des einmaligen Haiku-Passes (Praezision + Organisation + Dedup). Strikt add-only.
+-- Laufzeit liest NUR diese Tabelle (kein LLM live). [migration-approved]
+
+SET search_path TO compliance, public;
+
+DO $$
+BEGIN
+  IF EXISTS (SELECT 1 FROM information_schema.tables
+             WHERE table_schema = 'compliance'
+               AND table_name = 'canonical_controls') THEN
+
+    CREATE TABLE IF NOT EXISTS atom_classification (
+        control_uuid UUID NOT NULL
+            REFERENCES canonical_controls(id) ON DELETE CASCADE,
+        -- Registry-Key; KEIN SQL-CHECK -> neuer Use Case ohne Migration.
+        use_case VARCHAR(40) NOT NULL,
+        relevant BOOLEAN NOT NULL DEFAULT TRUE,
+        sub_topic VARCHAR(60),
+        canonical_obligation TEXT,
+        method VARCHAR(20) NOT NULL DEFAULT 'llm'
+            CHECK (method IN ('auto', 'manual', 'llm', 'seed')),
+        model VARCHAR(60),
+        created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+        updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+        PRIMARY KEY (control_uuid, use_case)
+    );
+    CREATE INDEX IF NOT EXISTS idx_atomcls_use_case
+        ON atom_classification(use_case);
+    CREATE INDEX IF NOT EXISTS idx_atomcls_uc_rel
+        ON atom_classification(use_case, relevant);
+    CREATE INDEX IF NOT EXISTS idx_atomcls_subtopic
+        ON atom_classification(use_case, sub_topic);
+
+  END IF;
+END $$;