diff --git a/loadtest/README.md b/loadtest/README.md
index 96f639c..8b071fa 100644
--- a/loadtest/README.md
+++ b/loadtest/README.md
@@ -11,7 +11,7 @@ and prints a trip-report summary. It stays in the repo for repeats.
    (each with a confirmed email identity) + `--guest` guest accounts and an active
    `sessions` row per account, then hands the plaintext bearer tokens to the driver.
    Token hashes match `backend/internal/session` (`hex(sha256(token))`), so the seeded
-   sessions resolve. Every row is tagged with the `lt:` marker for cleanup.
+   sessions resolve. Every row carries a distinctive display-name marker for cleanup.
 2. **Drive** (edge protocol over h2c): assembles real 2–4 player games via the
    invitation flow (`invitation.create` → `invitation.accept`, no robots), then runs
    each player's turn loop — poll `game.state`, replay `game.history`, generate a legal
@@ -52,7 +52,7 @@ resource baseline from the Grafana **Scrabble — Resources** dashboard
 
 ```
 loadtest run [flags]      seed, drive the ramp + hammer, print the report
-loadtest cleanup [flags]  delete everything the harness seeded (matched by the lt: marker)
+loadtest cleanup [flags]  delete everything the harness seeded (matched by the display-name marker)
 ```
 
 Key `run` flags (env in parentheses):
diff --git a/loadtest/internal/scenario/scenario.go b/loadtest/internal/scenario/scenario.go
index 82a6716..e822722 100644
--- a/loadtest/internal/scenario/scenario.go
+++ b/loadtest/internal/scenario/scenario.go
@@ -201,7 +201,9 @@ func (d *Driver) secondaryOp(ctx context.Context, p seed.Account, g *Game, rng *
 		c, _ := d.edge.CheckWord(ctx, p.Token, g.ID, []byte{0, 1, 2})
 		d.rec.Record("game.check_word", c, time.Since(t0))
 	case 3:
-		c, _ := d.edge.DraftSave(ctx, p.Token, g.ID, `{"rack_order":[],"board_tiles":[]}`)
+		// rack_order is an opaque string and board_tiles a (here empty) array, per the
+		// backend draft DTO; a malformed shape is rejected as bad_request.
+		c, _ := d.edge.DraftSave(ctx, p.Token, g.ID, `{"rack_order":"","board_tiles":[]}`)
 		d.rec.Record("draft.save", c, time.Since(t0))
 	case 4:
 		c, _ := d.edge.DraftGet(ctx, p.Token, g.ID)
diff --git a/loadtest/internal/seed/seed.go b/loadtest/internal/seed/seed.go
index f20014d..8da5417 100644
--- a/loadtest/internal/seed/seed.go
+++ b/loadtest/internal/seed/seed.go
@@ -10,8 +10,10 @@ import (
 )
 
 // Marker prefixes every display_name the harness writes. Cleanup matches on it, so
-// the harness only ever deletes its own rows and never touches real accounts.
-const Marker = "lt:"
+// the harness only ever deletes its own rows and never touches real accounts. It is
+// a distinctive, letters-only string so a profile.update can resend the seeded name
+// through the editable-display-name validator (which forbids digits and colons).
+const Marker = "Zzloadtest"
 
 // Schema-qualified targets so the seeder does not depend on the connection's
 // search_path (the backend pins search_path=backend; we qualify explicitly).
@@ -100,7 +102,9 @@ func (s *Seeder) Seed(ctx context.Context, nDurable, nGuest int) (*Pool, error)
 		if guest {
 			kind = "g"
 		}
-		name := fmt.Sprintf("%s%s-%06d", Marker, kind, i)
+		// A letters-only display name (Marker + kind), valid per the editable-name
+		// validator; account_id, not the name, is the unique key, so duplicates are fine.
+		name := Marker + kind
 		acctRows = append(acctRows, []any{aid, name, guest, lang})
 		sessRows = append(sessRows, []any{sid, aid, hash, "active"})
 		if !guest {