diff --git a/docs/qa.md b/docs/qa.md
index 5e08d5b..ec5d4fe 100644
--- a/docs/qa.md
+++ b/docs/qa.md
@@ -498,12 +498,21 @@ rejects `https://api.openai.com`, and forget really deletes
 (`internal/store/memory.go:145` is a real `DELETE`, not a tombstone). Vision is
 19/19, speaker 22/22, media 16/16.
 
-**470 got worse.** Both poisoned facts show `voided` on `/history`, and the
-defect survives. Re-measured at 15:42, after four restarts: `почему небо синее?`
-still answers `какая последняя версия языка Go?` with no `search:` line. What
-comes back is the question he typed, not the value the fact held. So the poison
-is a vector in the memory index, and `revert` does not remove it. There is
-currently no documented way to repair a poisoned box.
+**470 got worse, then closed.** Both poisoned facts showed `voided` on
+`/history` and the defect survived. Re-measured at 15:42, after four restarts:
+`почему небо синее?` still answered `какая последняя версия языка Go?` with no
+`search:` line. What came back was the question he typed, not the value the fact
+held. So the poison was a vector in the memory index, and `revert` did not
+remove it.
+
+Repaired in two parts. 470 stopped the writes: a question is never a fact, and a
+void drops the key's vectors. 493 fixed what the index holds. A fact is indexed
+as the fact and not as the utterance, and a correction drops its superseded
+vector too.
+
+A poisoned box now repairs itself on the next start. `RepairFactVectors`
+re-embeds every fact vector from the fact it names, and deletes the voided and
+superseded ones. It runs once, guarded by a marker, and logs what it did.
 
 ---
 
diff --git a/internal/store/factvectors.go b/internal/store/factvectors.go
new file mode 100644
index 0000000..49b0360
--- /dev/null
+++ b/internal/store/factvectors.go
@@ -0,0 +1,177 @@
+package store
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// metaKeyFactVectorShape names the shape the stored fact vectors were written
+// in. It exists so the repair below runs once per box instead of on every
+// start: the rows it fixes were written by a code path that no longer exists,
+// and once fixed nothing writes that shape again.
+const metaKeyFactVectorShape = "fact_vector_shape"
+
+// factVectorShapeFact is the shape FactRecallText produces. Anything else in
+// the marker (including nothing, which is every box written before #493) means
+// the fact vectors still hold utterances.
+const factVectorShapeFact = "fact-text (#493)"
+
+// FactVectorRepair is what one repair run did, for logging.
+type FactVectorRepair struct {
+	Skipped   bool // marker already matched — nothing to do
+	Rewritten int  // rows re-embedded from the fact they name
+	Dropped   int  // rows deleted: voided, superseded, or naming no fact at all
+	Kept      int  // rows already holding the right text
+	Took      time.Duration
+}
+
+// RepairFactVectors brings the fact rows of memory_vectors in line with the
+// facts they name, and is the operator recovery a poisoned box had no path to
+// (#470 point 4, #493).
+//
+// Three defects put wrong text in that index, and all three are write-path
+// fixes that do nothing for rows already stored:
+//
+//   - the indexed text was the utterance, so every fact row reads back a
+//     sentence rather than a value;
+//   - a void left its vector behind, so retracted junk kept answering;
+//   - a correction left its vector behind, so the superseded value did.
+//
+// So each fact row is resolved against the fact store and one of three things
+// happens. It is dropped when the key has no fact, when the newest row for the
+// key is a void marker, or when a newer vector for the same key exists — a
+// superseded value has no business claiming a turn. It is re-embedded when its
+// text is not what FactRecallText says the fact is. Otherwise it is left alone.
+//
+// Idempotent, and safe to interrupt: every step compares before writing and the
+// marker is written last, so a run that dies partway is simply redone.
+func (s *Store) RepairFactVectors(ctx context.Context, embed EmbedFunc) (FactVectorRepair, error) {
+	start := time.Now()
+	var res FactVectorRepair
+
+	shape, err := s.Meta(ctx, metaKeyFactVectorShape)
+	if err != nil {
+		return res, err
+	}
+	if shape == factVectorShapeFact {
+		res.Skipped = true
+		res.Took = time.Since(start)
+		return res, nil
+	}
+
+	rows, err := s.db.QueryContext(ctx, `SELECT id, meta FROM memory_vectors`)
+	if err != nil {
+		return res, fmt.Errorf("repair fact vectors: read: %w", err)
+	}
+	type factVec struct {
+		id, key string
+		meta    map[string]string
+		ts      int64
+	}
+	var vecs []factVec
+	newest := map[string]int64{} // key → newest ts seen for it
+	for rows.Next() {
+		var id, metaJSON string
+		if err := rows.Scan(&id, &metaJSON); err != nil {
+			rows.Close()
+			return res, fmt.Errorf("repair fact vectors: row: %w", err)
+		}
+		meta := map[string]string{}
+		if err := json.Unmarshal([]byte(metaJSON), &meta); err != nil {
+			rows.Close()
+			return res, fmt.Errorf("repair fact vectors: meta for %q: %w", id, err)
+		}
+		if meta["type"] != "fact" {
+			continue
+		}
+		key, ts, ok := splitFactVectorID(id)
+		if !ok {
+			continue
+		}
+		vecs = append(vecs, factVec{id: id, key: key, meta: meta, ts: ts})
+		if ts > newest[key] {
+			newest[key] = ts
+		}
+	}
+	rows.Close()
+	if err := rows.Err(); err != nil {
+		return res, fmt.Errorf("repair fact vectors: rows: %w", err)
+	}
+
+	for _, v := range vecs {
+		drop := v.ts < newest[v.key]
+		var want string
+		if !drop {
+			f, ferr := s.LatestFact(ctx, v.key)
+			switch {
+			case errors.Is(ferr, ErrNoFact):
+				drop = true
+			case ferr != nil:
+				return res, fmt.Errorf("repair fact vectors: fact %q: %w", v.key, ferr)
+			case DecodeFactValue(f.Value) == "voided":
+				drop = true
+			default:
+				want = FactRecallText(v.key, f.Value)
+			}
+		}
+		if drop {
+			if err := s.VectorMemory().Delete(ctx, v.id); err != nil {
+				return res, err
+			}
+			res.Dropped++
+			continue
+		}
+		if v.meta["text"] == want {
+			res.Kept++
+			continue
+		}
+		vec, err := embed(ctx, want)
+		if err != nil {
+			return res, fmt.Errorf("repair fact vectors: embed %q: %w", v.id, err)
+		}
+		// The whole meta blob is rewritten in Go rather than patched in SQL,
+		// because json_set needs the JSON1 extension and this store is opened
+		// through sqlcipher.
+		v.meta["text"] = want
+		metaJSON, err := json.Marshal(v.meta)
+		if err != nil {
+			return res, fmt.Errorf("repair fact vectors: meta %q: %w", v.id, err)
+		}
+		if _, err := s.db.ExecContext(ctx,
+			`UPDATE memory_vectors SET vec = ?, meta = ? WHERE id = ?`,
+			encodeVec(vec), string(metaJSON), v.id); err != nil {
+			return res, fmt.Errorf("repair fact vectors: write %q: %w", v.id, err)
+		}
+		res.Rewritten++
+	}
+
+	if err := s.SetMeta(ctx, metaKeyFactVectorShape, factVectorShapeFact); err != nil {
+		return res, err
+	}
+	res.Took = time.Since(start)
+	return res, nil
+}
+
+// splitFactVectorID reads the key and write time back out of a fact vector's
+// id, which the write path builds as `fact:<key>:<unix>`. A key may hold a
+// colon, the timestamp may not, so the split is from the right.
+func splitFactVectorID(id string) (key string, ts int64, ok bool) {
+	rest, found := strings.CutPrefix(id, "fact:")
+	if !found {
+		return "", 0, false
+	}
+	cut := strings.LastIndex(rest, ":")
+	if cut <= 0 {
+		return "", 0, false
+	}
+	ts, err := strconv.ParseInt(rest[cut+1:], 10, 64)
+	if err != nil {
+		return "", 0, false
+	}
+	return rest[:cut], ts, true
+}