R7: pin docker_stats api_version to 1.44

The receiver defaults to Docker API 1.25, but the contour daemon's minimum is
1.40 (it speaks up to 1.54), so otelcol crash-looped on start with "client
version 1.25 is too old". Pinning api_version to 1.44 (accepted by both the
receiver's bundled client and the daemon) starts the receiver cleanly —
verified by running the image against the host socket ("Everything is ready",
no start error).

deploy/docker-compose.yml

@@ -39,6 +39,13 @@ services:
       retries: 30
     volumes:
       - postgres-data:/var/lib/postgresql/data
+    # R7 starting limits: 512M leaves headroom over the default 128 MB shared_buffers +
+    # per-connection memory (R2 peaked at 28 backends / 69 MiB RSS); tighten after the run.
+    deploy:
+      resources:
+        limits:
+          cpus: "2.0"
+          memory: 512M
     networks: [internal]
 
   backend:
@@ -65,8 +72,19 @@ services:
       BACKEND_OTEL_METRICS_EXPORTER: otlp
       OTEL_EXPORTER_OTLP_ENDPOINT: http://otelcol:4317
       OTEL_EXPORTER_OTLP_INSECURE: "true"
+      # GOMAXPROCS matches the CPU limit below so the Go scheduler aligns with the
+      # cgroup quota (the runtime otherwise sees all of the host's cores).
+      GOMAXPROCS: "2"
     # No container healthcheck: the distroless image has no shell/wget. Readiness
     # is covered by the CI post-deploy probe (GET / through caddy).
+    # R7 starting limits (generous over the R2 ~1-core / <=100 MiB peak); tightened to
+    # the agreed prod values after the final stress run. deploy.resources.limits is
+    # honoured by `docker compose up` (Compose v2), not only by swarm.
+    deploy:
+      resources:
+        limits:
+          cpus: "2.0"
+          memory: 512M
     networks: [internal]
 
   gateway:
@@ -97,8 +115,17 @@ services:
       GATEWAY_OTEL_METRICS_EXPORTER: otlp
       OTEL_EXPORTER_OTLP_ENDPOINT: http://otelcol:4317
       OTEL_EXPORTER_OTLP_INSECURE: "true"
+      # GOMAXPROCS matches the CPU limit below (see backend).
+      GOMAXPROCS: "2"
       # GATEWAY_ADMIN_* intentionally unset: in the deployed contour the front
       # caddy owns the /_gm Basic-Auth and routes /_gm to the backend directly.
+    # R7 starting limits (generous over the R2 ~1-core / <=100 MiB peak); tighten after
+    # the final stress run.
+    deploy:
+      resources:
+        limits:
+          cpus: "2.0"
+          memory: 512M
     networks: [internal]
 
   # --- Landing (static) -------------------------------------------------------
@@ -121,6 +148,10 @@ services:
         VITE_GATEWAY_URL: ${VITE_GATEWAY_URL:-}
         VITE_APP_VERSION: ${APP_VERSION:-dev}
     restart: unless-stopped
+    deploy:
+      resources:
+        limits:
+          memory: 128M
     networks: [internal]
 
   # --- Telegram connector (egress via the VPN sidecar) -----------------------
@@ -167,6 +198,13 @@ services:
       TELEGRAM_OTEL_METRICS_EXPORTER: otlp
       OTEL_EXPORTER_OTLP_ENDPOINT: http://otelcol:4317
       OTEL_EXPORTER_OTLP_INSECURE: "true"
+      # The connector is light (the stress run does not drive Telegram); one P suffices.
+      GOMAXPROCS: "1"
+    deploy:
+      resources:
+        limits:
+          cpus: "1.0"
+          memory: 256M
 
   # --- Edge reverse proxy (single /_gm Basic-Auth; SPA + Connect -> gateway;
   #     the catch-all incl. the landing -> the static landing container) -------
@@ -183,6 +221,10 @@ services:
     volumes:
       - ${SCRABBLE_CONFIG_DIR:-.}/caddy/Caddyfile:/etc/caddy/Caddyfile:ro
       - caddy-data:/data
+    deploy:
+      resources:
+        limits:
+          memory: 128M
     networks:
       internal: {}
       edge:
@@ -194,8 +236,19 @@ services:
     image: otel/opentelemetry-collector-contrib:0.119.0
     restart: unless-stopped
     command: ["--config=/etc/otelcol/config.yaml"]
+    # The docker_stats receiver reads per-container metrics from the Docker API, so the
+    # collector (image UID 10001) joins the host's docker group to read the socket —
+    # DOCKER_GID defaults to the contour host's 989; set it for other hosts (prod). The
+    # socket is mounted read-only. This replaces cAdvisor, whose per-container metrics
+    # are empty on this host (separate-XFS /var/lib/docker).
+    group_add: ["${DOCKER_GID:-989}"]
     volumes:
       - ${SCRABBLE_CONFIG_DIR:-.}/otelcol/config.yaml:/etc/otelcol/config.yaml:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+    deploy:
+      resources:
+        limits:
+          memory: 512M
     networks: [internal]
 
   prometheus:
@@ -208,6 +261,10 @@ services:
     volumes:
       - ${SCRABBLE_CONFIG_DIR:-.}/prometheus/prometheus.yml:/etc/prometheus/prometheus.yml:ro
       - prometheus-data:/prometheus
+    deploy:
+      resources:
+        limits:
+          memory: 512M
     networks: [internal]
 
   tempo:
@@ -218,6 +275,11 @@ services:
     volumes:
       - ${SCRABBLE_CONFIG_DIR:-.}/tempo/tempo.yaml:/etc/tempo/tempo.yaml:ro
       - tempo-data:/var/tempo
+    # tempo peaked at ~446 MiB in R2; 1G leaves headroom for the final run.
+    deploy:
+      resources:
+        limits:
+          memory: 1G
     networks: [internal]
 
   grafana:
@@ -247,26 +309,10 @@ services:
       # provider logs "no such file or directory").
       - ${SCRABBLE_CONFIG_DIR:-.}/grafana/dashboards:/etc/grafana/dashboards:ro
       - grafana-data:/var/lib/grafana
-    networks: [internal]
-
-  # cAdvisor exports per-container resource metrics (CPU / memory / network / disk)
-  # for the R2/R7 stress runs' resource baseline. Prometheus scrapes it at :8080
-  # over the internal network. It needs read access to the host's cgroup and
-  # container state; --docker_only trims non-container cgroup series.
-  cadvisor:
-    container_name: scrabble-cadvisor
-    image: gcr.io/cadvisor/cadvisor:v0.49.1
-    restart: unless-stopped
-    privileged: true
-    command: ["--docker_only=true", "--housekeeping_interval=15s"]
-    devices:
-      - /dev/kmsg
-    volumes:
-      - /:/rootfs:ro
-      - /var/run:/var/run:ro
-      - /sys:/sys:ro
-      - /var/lib/docker/:/var/lib/docker:ro
-      - /dev/disk/:/dev/disk:ro
+    deploy:
+      resources:
+        limits:
+          memory: 512M
     networks: [internal]
 
   # postgres_exporter exports Postgres server metrics (connections, cache hit ratio,
@@ -279,6 +325,10 @@ services:
     depends_on: [postgres]
     environment:
       DATA_SOURCE_NAME: postgresql://${POSTGRES_USER:-scrabble}:${POSTGRES_PASSWORD}@postgres:5432/${POSTGRES_DB:-scrabble}?sslmode=disable
+    deploy:
+      resources:
+        limits:
+          memory: 128M
     networks: [internal]
 
 networks:

deploy/grafana/dashboards/resources.json

@@ -4,7 +4,7 @@
   "tags": ["scrabble"],
   "timezone": "",
   "schemaVersion": 39,
-  "version": 1,
+  "version": 2,
   "refresh": "30s",
   "time": { "from": "now-1h", "to": "now" },
   "panels": [
@@ -43,30 +43,30 @@
     {
       "type": "timeseries",
       "title": "Container CPU (cores) by container",
-      "description": "cAdvisor container_cpu_usage_seconds_total rate, per scrabble-* container (the load harness appears when run as --name scrabble-loadtest). Verify the metric name against live Prometheus if empty.",
+      "description": "docker_stats container.cpu.utilization (a gauge where 100 == one core) / 100, per scrabble-* container; the load harness appears when run as --name scrabble-loadtest. Verify the scaling against live Prometheus.",
       "gridPos": { "h": 8, "w": 12, "x": 0, "y": 5 },
       "datasource": { "type": "prometheus", "uid": "prometheus" },
-      "targets": [{ "refId": "A", "expr": "sum(rate(container_cpu_usage_seconds_total{name=~\"scrabble-.+\"}[5m])) by (name)", "legendFormat": "{{name}}" }]
+      "targets": [{ "refId": "A", "expr": "max(container_cpu_utilization{container_name=~\"scrabble-.+\"}) by (container_name) / 100", "legendFormat": "{{container_name}}" }]
     },
     {
       "type": "timeseries",
-      "title": "Container memory (working set) by container",
-      "description": "cAdvisor container_memory_working_set_bytes, per scrabble-* container.",
+      "title": "Container memory (usage) by container",
+      "description": "docker_stats container.memory.usage.total bytes, per scrabble-* container.",
       "gridPos": { "h": 8, "w": 12, "x": 12, "y": 5 },
       "fieldConfig": { "defaults": { "unit": "bytes" }, "overrides": [] },
       "datasource": { "type": "prometheus", "uid": "prometheus" },
-      "targets": [{ "refId": "A", "expr": "max(container_memory_working_set_bytes{name=~\"scrabble-.+\"}) by (name)", "legendFormat": "{{name}}" }]
+      "targets": [{ "refId": "A", "expr": "max(container_memory_usage_total{container_name=~\"scrabble-.+\"}) by (container_name)", "legendFormat": "{{container_name}}" }]
     },
     {
       "type": "timeseries",
       "title": "Container network I/O by container",
-      "description": "cAdvisor receive (+) and transmit (-) byte rates per scrabble-* container.",
+      "description": "docker_stats receive (+) and transmit (-) byte rates per scrabble-* container (summed across interfaces).",
       "gridPos": { "h": 8, "w": 12, "x": 0, "y": 13 },
       "fieldConfig": { "defaults": { "unit": "Bps" }, "overrides": [] },
       "datasource": { "type": "prometheus", "uid": "prometheus" },
       "targets": [
-        { "refId": "A", "expr": "sum(rate(container_network_receive_bytes_total{name=~\"scrabble-.+\"}[5m])) by (name)", "legendFormat": "rx {{name}}" },
-        { "refId": "B", "expr": "-sum(rate(container_network_transmit_bytes_total{name=~\"scrabble-.+\"}[5m])) by (name)", "legendFormat": "tx {{name}}" }
+        { "refId": "A", "expr": "sum(rate(container_network_io_usage_rx_bytes{container_name=~\"scrabble-.+\"}[5m])) by (container_name)", "legendFormat": "rx {{container_name}}" },
+        { "refId": "B", "expr": "-sum(rate(container_network_io_usage_tx_bytes{container_name=~\"scrabble-.+\"}[5m])) by (container_name)", "legendFormat": "tx {{container_name}}" }
       ]
     },
     {

deploy/otelcol/config.yaml

@@ -6,6 +6,22 @@ receivers:
     protocols:
       grpc:
         endpoint: 0.0.0.0:4317
+  # Per-container resource metrics (CPU / memory / network) read straight from the
+  # Docker API. This replaces cAdvisor, which on the contour host resolves only the
+  # root cgroup (its /var/lib/docker is a separate XFS mount), and works the same in
+  # prod. The collector reaches the socket via group_add in docker-compose.yml.
+  # collection_interval matches Prometheus' 30s scrape. container.cpu.utilization is a
+  # gauge where 100 == one core (it mirrors `docker stats` CPU%).
+  docker_stats:
+    endpoint: unix:///var/run/docker.sock
+    # The receiver defaults to Docker API 1.25, but the daemon's minimum is 1.40
+    # (server speaks up to 1.54); pin a version both the receiver's client and the
+    # daemon accept, else the receiver fails to start ("client version too old").
+    api_version: "1.44"
+    collection_interval: 30s
+    metrics:
+      container.cpu.utilization:
+        enabled: true
 
 processors:
   batch: {}
@@ -33,6 +49,6 @@ service:
       processors: [batch]
       exporters: [otlp/tempo]
     metrics:
-      receivers: [otlp]
+      receivers: [otlp, docker_stats]
       processors: [batch]
       exporters: [prometheus]

deploy/prometheus/prometheus.yml

@@ -6,17 +6,14 @@ global:
   evaluation_interval: 30s
 
 scrape_configs:
+  # otelcol exposes both the services' OTLP metrics and the docker_stats receiver's
+  # per-container resource metrics (CPU/memory/network) on one endpoint.
   - job_name: otelcol
     static_configs:
       - targets: ["otelcol:9464"]
   - job_name: prometheus
     static_configs:
       - targets: ["localhost:9090"]
-  # Container resource metrics (CPU/memory/network/disk) for every contour
-  # container, for the R2/R7 stress runs' resource baseline.
-  - job_name: cadvisor
-    static_configs:
-      - targets: ["cadvisor:8080"]
   # Postgres server metrics (connections, cache hit ratio, transactions, db size).
   - job_name: postgres_exporter
     static_configs:

loadtest/cmd/loadtest/main.go

@@ -24,7 +24,6 @@ import (
 	"syscall"
 	"time"
 
-	"scrabble/loadtest/internal/edge"
 	"scrabble/loadtest/internal/moves"
 	"scrabble/loadtest/internal/report"
 	"scrabble/loadtest/internal/scenario"
@@ -114,7 +113,7 @@ func cmdRun(ctx context.Context, log *slog.Logger, args []string) error {
 	log.Info("seeded", "durable", len(pool.Durables), "guest", len(pool.Guests))
 
 	rec := report.New()
-	drv := scenario.NewDriver(edge.New(*gateway), reg, rec, log)
+	drv := scenario.NewDriver(*gateway, reg, rec, log)
 	cfg := scenario.RealisticConfig{
 		Steps: steps, StepDur: *stepDur, GamesPerPlayer: *gpp,
 		Tick: *tick, SecondaryProb: *secProb,

loadtest/internal/edge/client.go

@@ -41,16 +41,18 @@ const (
 	msgEnqueue    = "lobby.enqueue"
 )
 
-// Client speaks the edge protocol to a single gateway base URL over h2c. It is safe
-// for concurrent use by many virtual players (the underlying http2.Transport pools
-// and multiplexes connections).
+// Client speaks the edge protocol to a single gateway base URL over h2c. The harness
+// builds one Client per virtual player, so each player owns its h2c connection (its
+// Subscribe stream and Execute calls share it) the way a real client does; a single
+// Client is safe for that player's own concurrent goroutines.
 type Client struct {
 	rpc edgev1connect.GatewayClient
 }
 
 // New builds a Client for baseURL (for example http://gateway:8081). The transport
 // speaks HTTP/2 cleartext (h2c) to match the gateway, dialling plaintext TCP rather
-// than TLS.
+// than TLS. Each virtual player gets its own Client (hence its own connection), so the
+// load mirrors real clients instead of multiplexing every player over one transport.
 func New(baseURL string) *Client {
 	hc := &http.Client{
 		Transport: &http2.Transport{

loadtest/internal/scenario/assemble.go

@@ -37,6 +37,7 @@ func (d *Driver) assembleCohort(ctx context.Context, cohort []seed.Account, game
 	if len(cohort) < 2 {
 		return nil
 	}
+	c := edge.New(d.gateway) // one client for the assembly burst; players play on their own
 	gamesOf := make(map[string]int, len(cohort))
 	var games []*Game
 	for i := range cohort {
@@ -51,7 +52,7 @@ func (d *Driver) assembleCohort(ctx context.Context, cohort []seed.Account, game
 				break
 			}
 			variant := moves.Variants()[rng.Intn(len(moves.Variants()))]
-			g, err := d.assemble(ctx, members, variant)
+			g, err := d.assemble(ctx, c, members, variant)
 			if err != nil {
 				d.log.Debug("assemble game", "err", err)
 				break
@@ -85,7 +86,7 @@ func pickMembers(cohort []seed.Account, inviter seed.Account, rng *rand.Rand) []
 // assemble runs the invitation flow for one game: the inviter (members[0]) invites
 // the rest, each invitee accepts the pending invitation, and the completing accept
 // starts the game, which is then located in the inviter's game list.
-func (d *Driver) assemble(ctx context.Context, members []seed.Account, variant string) (*Game, error) {
+func (d *Driver) assemble(ctx context.Context, c *edge.Client, members []seed.Account, variant string) (*Game, error) {
 	inviter := members[0]
 	inviteeIDs := make([]string, len(members)-1)
 	for i, m := range members[1:] {
@@ -93,7 +94,7 @@ func (d *Driver) assemble(ctx context.Context, members []seed.Account, variant s
 	}
 
 	t0 := time.Now()
-	code, err := d.edge.CreateInvitation(ctx, inviter.Token, inviteeIDs, variant)
+	code, err := c.CreateInvitation(ctx, inviter.Token, inviteeIDs, variant)
 	d.rec.Record("invitation.create", code, time.Since(t0))
 	if err != nil || code != "ok" {
 		return nil, fmt.Errorf("invitation.create: %s", code)
@@ -101,7 +102,7 @@ func (d *Driver) assemble(ctx context.Context, members []seed.Account, variant s
 
 	for _, invitee := range members[1:] {
 		t0 = time.Now()
-		list, lc, err := d.edge.ListInvitations(ctx, invitee.Token)
+		list, lc, err := c.ListInvitations(ctx, invitee.Token)
 		d.rec.Record("invitation.list", lc, time.Since(t0))
 		if err != nil || lc != "ok" {
 			return nil, fmt.Errorf("invitation.list: %s", lc)
@@ -111,7 +112,7 @@ func (d *Driver) assemble(ctx context.Context, members []seed.Account, variant s
 			return nil, fmt.Errorf("no pending invitation from %s", inviter.ID)
 		}
 		t0 = time.Now()
-		ac, err := d.edge.AcceptInvitation(ctx, invitee.Token, invID)
+		ac, err := c.AcceptInvitation(ctx, invitee.Token, invID)
 		d.rec.Record("invitation.accept", ac, time.Since(t0))
 		if err != nil || ac != "ok" {
 			return nil, fmt.Errorf("invitation.accept: %s", ac)
@@ -119,7 +120,7 @@ func (d *Driver) assemble(ctx context.Context, members []seed.Account, variant s
 	}
 
 	t0 = time.Now()
-	games, gc, err := d.edge.GamesList(ctx, inviter.Token)
+	games, gc, err := c.GamesList(ctx, inviter.Token)
 	d.rec.Record("games.list", gc, time.Since(t0))
 	if err != nil || gc != "ok" {
 		return nil, fmt.Errorf("games.list: %s", gc)

loadtest/internal/scenario/hammer.go

@@ -5,6 +5,7 @@ import (
 	"sync"
 	"time"
 
+	"scrabble/loadtest/internal/edge"
 	"scrabble/loadtest/internal/seed"
 )
 
@@ -29,6 +30,7 @@ func (d *Driver) Hammer(ctx context.Context, acc seed.Account, cfg HammerConfig)
 	runCtx, cancel := context.WithTimeout(ctx, cfg.Duration)
 	defer cancel()
 	d.log.Info("gateway-hammer", "workers", cfg.Workers, "duration", cfg.Duration)
+	c := edge.New(d.gateway)
 	var wg sync.WaitGroup
 	for w := 0; w < cfg.Workers; w++ {
 		wg.Add(1)
@@ -36,7 +38,7 @@ func (d *Driver) Hammer(ctx context.Context, acc seed.Account, cfg HammerConfig)
 			defer wg.Done()
 			for runCtx.Err() == nil {
 				t0 := time.Now()
-				_, code, _ := d.edge.GamesList(runCtx, acc.Token)
+				_, code, _ := c.GamesList(runCtx, acc.Token)
 				d.rec.Record("hammer:games.list", code, time.Since(t0))
 			}
 		}()

loadtest/internal/scenario/scenario.go

@@ -9,6 +9,7 @@ import (
 	"context"
 	"log/slog"
 	"math/rand"
+	"slices"
 	"sync"
 	"time"
 
@@ -18,18 +19,20 @@ import (
 	"scrabble/loadtest/internal/seed"
 )
 
-// Driver ties the edge client, the local move generator and the run recorder
-// together. All three are safe for concurrent use by many player goroutines.
+// Driver ties the gateway endpoint, the local move generator and the run recorder
+// together. It builds one edge client per virtual player, so each player owns its
+// h2c connection (its Subscribe stream and Execute calls share it) the way a real
+// client does, rather than multiplexing every player over a single shared transport.
 type Driver struct {
-	edge  *edge.Client
+	gateway string // gateway base URL, e.g. http://gateway:8081
 	moves   *moves.Registry
 	rec     *report.Recorder
 	log     *slog.Logger
 }
 
-// NewDriver builds a Driver.
-func NewDriver(c *edge.Client, m *moves.Registry, rec *report.Recorder, log *slog.Logger) *Driver {
-	return &Driver{edge: c, moves: m, rec: rec, log: log}
+// NewDriver builds a Driver targeting the gateway base URL.
+func NewDriver(gateway string, m *moves.Registry, rec *report.Recorder, log *slog.Logger) *Driver {
+	return &Driver{gateway: gateway, moves: m, rec: rec, log: log}
 }
 
 // RealisticConfig parameterises the under-the-limit ramp.
@@ -98,11 +101,16 @@ func (d *Driver) RunRealistic(ctx context.Context, pool *seed.Pool, cfg Realisti
 	return nil
 }
 
-// playerLoop runs one virtual player: a live-event subscription (loads the push hub,
-// counts events) plus a round-robin turn loop over the player's games.
+// playerLoop runs one virtual player over its own edge client (its own h2c
+// connection): a live-event subscription (loads the push hub, counts events) plus a
+// round-robin turn loop over the player's games. A game that has finished is dropped
+// from the rotation so secondary ops stop hitting an ended game; once no active game
+// remains the player idles, still holding its stream, until the run ends.
 func (d *Driver) playerLoop(ctx context.Context, p seed.Account, games []*Game, cfg RealisticConfig, rng *rand.Rand) {
-	go d.subscribeLoop(ctx, p)
-	if len(games) == 0 {
+	c := edge.New(d.gateway)
+	go d.subscribeLoop(ctx, c, p)
+	active := games
+	if len(active) == 0 {
 		<-ctx.Done()
 		return
 	}
@@ -114,22 +122,30 @@ func (d *Driver) playerLoop(ctx context.Context, p seed.Account, games []*Game,
 		case <-ctx.Done():
 			return
 		case <-ticker.C:
-			g := games[gi%len(games)]
+			g := active[gi%len(active)]
 			gi++
 			if rng.Float64() < cfg.SecondaryProb {
-				d.secondaryOp(ctx, p, g, rng)
+				d.secondaryOp(ctx, c, p, g, rng)
 				continue
 			}
-			d.playTurn(ctx, p, g, rng)
+			if d.playTurn(ctx, c, p, g, rng) {
+				active = slices.DeleteFunc(active, func(x *Game) bool { return x == g })
+				gi = 0
+				if len(active) == 0 {
+					<-ctx.Done()
+					return
+				}
+			}
 		}
 	}
 }
 
-// subscribeLoop holds the player's live-event stream open, counting events and
-// reconnecting with a brief backoff after a drop, until the run ends.
-func (d *Driver) subscribeLoop(ctx context.Context, p seed.Account) {
+// subscribeLoop holds the player's live-event stream open on the player's client,
+// counting events and reconnecting with a brief backoff after a drop, until the run
+// ends.
+func (d *Driver) subscribeLoop(ctx context.Context, c *edge.Client, p seed.Account) {
 	for ctx.Err() == nil {
-		err := d.edge.Subscribe(ctx, p.Token, func(e edge.Event) { d.rec.Event(e.Kind) })
+		err := c.Subscribe(ctx, p.Token, func(e edge.Event) { d.rec.Event(e.Kind) })
 		if ctx.Err() != nil {
 			return
 		}
@@ -144,80 +160,90 @@ func (d *Driver) subscribeLoop(ctx context.Context, p seed.Account) {
 	}
 }
 
-// playTurn plays one turn in g when it is the player's move: fetch state, replay
-// history, pick a legal move and submit it (or exchange / pass).
-func (d *Driver) playTurn(ctx context.Context, p seed.Account, g *Game, rng *rand.Rand) {
+// playTurn plays one turn in g over the player's client when it is the player's
+// move: fetch state, replay history, pick a legal move and submit it (or exchange /
+// pass). It reports whether the game has finished, so the caller can drop it from the
+// rotation.
+func (d *Driver) playTurn(ctx context.Context, c *edge.Client, p seed.Account, g *Game, rng *rand.Rand) (finished bool) {
 	seat := g.seatOf(p.ID.String())
 	if seat < 0 {
-		return
+		return false
 	}
 	t0 := time.Now()
-	st, code, err := d.edge.State(ctx, p.Token, g.ID)
+	st, code, err := c.State(ctx, p.Token, g.ID)
 	d.rec.Record("game.state", code, time.Since(t0))
-	if err != nil || code != "ok" || !st.Game.Active() || st.Game.ToMove != seat {
-		return
+	if err != nil || code != "ok" {
+		return false
+	}
+	if !st.Game.Active() {
+		return true
+	}
+	if st.Game.ToMove != seat {
+		return false
 	}
 
 	t0 = time.Now()
-	hist, hc, err := d.edge.History(ctx, p.Token, g.ID)
+	hist, hc, err := c.History(ctx, p.Token, g.ID)
 	d.rec.Record("game.history", hc, time.Since(t0))
 	if err != nil || hc != "ok" {
-		return
+		return false
 	}
 
 	action, err := d.moves.Pick(g.Variant, hist, st.Rack, st.BagLen, rng)
 	if err != nil {
 		d.log.Debug("pick move", "variant", g.Variant, "err", err)
-		return
+		return false
 	}
 	switch action.Kind {
 	case "play":
 		t0 = time.Now()
-		_, c, _ := d.edge.SubmitPlay(ctx, p.Token, g.ID, action.Dir, action.Tiles)
-		d.rec.Record("game.submit_play", c, time.Since(t0))
+		_, code, _ := c.SubmitPlay(ctx, p.Token, g.ID, action.Dir, action.Tiles)
+		d.rec.Record("game.submit_play", code, time.Since(t0))
 	case "exchange":
 		t0 = time.Now()
-		_, c, _ := d.edge.Exchange(ctx, p.Token, g.ID, action.Exchange)
-		d.rec.Record("game.exchange", c, time.Since(t0))
+		_, code, _ := c.Exchange(ctx, p.Token, g.ID, action.Exchange)
+		d.rec.Record("game.exchange", code, time.Since(t0))
 	default:
 		t0 = time.Now()
-		_, c, _ := d.edge.Pass(ctx, p.Token, g.ID)
-		d.rec.Record("game.pass", c, time.Since(t0))
+		_, code, _ := c.Pass(ctx, p.Token, g.ID)
+		d.rec.Record("game.pass", code, time.Since(t0))
 	}
+	return false
 }
 
 // secondaryOp exercises one of the non-move edge operations the plan calls out, so
-// the run touches nudge / chat / check-word / draft / profile / stats too.
-func (d *Driver) secondaryOp(ctx context.Context, p seed.Account, g *Game, rng *rand.Rand) {
+// the run touches nudge / chat / check-word / draft / profile / stats too, over the
+// player's own client.
+func (d *Driver) secondaryOp(ctx context.Context, c *edge.Client, p seed.Account, g *Game, rng *rand.Rand) {
 	t0 := time.Now()
 	switch rng.Intn(7) {
 	case 0:
-		c, _ := d.edge.Nudge(ctx, p.Token, g.ID)
-		d.rec.Record("chat.nudge", c, time.Since(t0))
+		code, _ := c.Nudge(ctx, p.Token, g.ID)
+		d.rec.Record("chat.nudge", code, time.Since(t0))
 	case 1:
-		c, _ := d.edge.ChatPost(ctx, p.Token, g.ID, "gg")
-		d.rec.Record("chat.post", c, time.Since(t0))
+		code, _ := c.ChatPost(ctx, p.Token, g.ID, "gg")
+		d.rec.Record("chat.post", code, time.Since(t0))
 	case 2:
-		c, _ := d.edge.CheckWord(ctx, p.Token, g.ID, []byte{0, 1, 2})
-		d.rec.Record("game.check_word", c, time.Since(t0))
+		code, _ := c.CheckWord(ctx, p.Token, g.ID, []byte{0, 1, 2})
+		d.rec.Record("game.check_word", code, time.Since(t0))
 	case 3:
 		// 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))
+		code, _ := c.DraftSave(ctx, p.Token, g.ID, `{"rack_order":"","board_tiles":[]}`)
+		d.rec.Record("draft.save", code, time.Since(t0))
 	case 4:
-		c, _ := d.edge.DraftGet(ctx, p.Token, g.ID)
-		d.rec.Record("draft.get", c, time.Since(t0))
+		code, _ := c.DraftGet(ctx, p.Token, g.ID)
+		d.rec.Record("draft.get", code, time.Since(t0))
 	case 5:
 		lang := "en"
 		if rng.Intn(2) == 1 {
 			lang = "ru"
 		}
-		c, _ := d.edge.ProfileUpdate(ctx, p.Token, p.Name, lang)
-		d.rec.Record("profile.update", c, time.Since(t0))
+		code, _ := c.ProfileUpdate(ctx, p.Token, p.Name, lang)
+		d.rec.Record("profile.update", code, time.Since(t0))
 	default:
-		c, _ := d.edge.Stats(ctx, p.Token)
-		d.rec.Record("stats.get", c, time.Since(t0))
+		code, _ := c.Stats(ctx, p.Token)
+		d.rec.Record("stats.get", code, time.Since(t0))
 	}
 }