diff --git a/internal/identity/pending_count_index_test.go b/internal/identity/pending_count_index_test.go
new file mode 100644
index 000000000..ea6914d37
--- /dev/null
+++ b/internal/identity/pending_count_index_test.go
@@ -0,0 +1,126 @@
+package identity_test
+
+import (
+	"context"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/tokencanopy/e2a/internal/identity"
+	"github.com/tokencanopy/e2a/internal/testutil"
+	"github.com/tokencanopy/e2a/migrations"
+)
+
+func TestPendingCountIndexMigration(t *testing.T) {
+	pool := testutil.TestDB(t)
+	ctx := context.Background()
+
+	// TestDB applies the embedded migrations through the real runner. Reapply
+	// the index statement directly to also exercise its IF NOT EXISTS retry.
+	sql, err := migrations.FS.ReadFile("133_messages_agent_pending_idx.sql")
+	if err != nil {
+		t.Fatalf("read pending-count migration: %v", err)
+	}
+	if _, err := pool.Exec(ctx, string(sql)); err != nil {
+		t.Fatalf("reapply pending-count migration: %v", err)
+	}
+
+	var definition string
+	var valid, ready bool
+	if err := pool.QueryRow(ctx,
+		`SELECT pg_get_indexdef(indexrelid), indisvalid, indisready
+		   FROM pg_index
+		  WHERE indexrelid = 'idx_messages_agent_pending'::regclass
+		    AND indrelid = 'messages'::regclass`,
+	).Scan(&definition, &valid, &ready); err != nil {
+		t.Fatalf("read pending-count index: %v", err)
+	}
+	if !valid || !ready {
+		t.Fatalf("pending-count index valid=%t ready=%t, want both true", valid, ready)
+	}
+	for _, fragment := range []string{
+		"USING btree (agent_id) WHERE",
+		"status = 'pending_review'",
+		"direction = 'outbound'",
+	} {
+		if !strings.Contains(definition, fragment) {
+			t.Fatalf("pending-count index definition %q missing %q", definition, fragment)
+		}
+	}
+}
+
+func TestListAgentsByUserPendingCountScopesOutboundHolds(t *testing.T) {
+	pool := testutil.TestDB(t)
+	store := identity.NewStore(pool)
+	ctx := context.Background()
+
+	user, first := setupPendingAgent(t, store, "pending-count")
+	second, err := store.CreateAgent(ctx, "second@pending-count.example.com", first.Domain, "", "", "", user.ID)
+	if err != nil {
+		t.Fatalf("create second agent: %v", err)
+	}
+	_, otherOwner := setupPendingAgent(t, store, "pending-count-other")
+
+	// Counts are all-time, per-agent outbound holds, not all review items or
+	// the seven-day activity totals returned by the neighboring subqueries.
+	rows := []struct {
+		id        string
+		agentID   string
+		direction string
+		status    string
+		ageDays   int
+	}{
+		{"msg_pending_count_recent", first.ID, "outbound", "pending_review", 0},
+		{"msg_pending_count_old", first.ID, "outbound", "pending_review", 14},
+		{"msg_pending_count_inbound", first.ID, "inbound", "pending_review", 0},
+		{"msg_pending_count_sent", first.ID, "outbound", "sent", 0},
+		{"msg_pending_count_approved", first.ID, "inbound", "review_approved", 0},
+		{"msg_pending_count_rejected", first.ID, "outbound", "review_rejected", 0},
+		{"msg_pending_count_expired_approved", first.ID, "outbound", "review_expired_approved", 0},
+		{"msg_pending_count_expired_rejected", first.ID, "outbound", "review_expired_rejected", 0},
+		{"msg_pending_count_second", second.ID, "outbound", "pending_review", 0},
+		{"msg_pending_count_other_owner", otherOwner.ID, "outbound", "pending_review", 0},
+	}
+	for _, row := range rows {
+		if _, err := pool.Exec(ctx,
+			`INSERT INTO messages (id, agent_id, direction, status, created_at)
+			 VALUES ($1, $2, $3, $4, now() - make_interval(days => $5))`,
+			row.id, row.agentID, row.direction, row.status, row.ageDays,
+		); err != nil {
+			t.Fatalf("seed %s: %v", row.id, err)
+		}
+	}
+
+	assertCounts := func(wantFirst int) {
+		t.Helper()
+		agents, err := store.ListAgentsByUser(ctx, user.ID, 0, time.Time{}, "")
+		if err != nil {
+			t.Fatalf("ListAgentsByUser: %v", err)
+		}
+		if len(agents) != 2 {
+			t.Fatalf("agent count = %d, want 2 for the requested owner", len(agents))
+		}
+		want := map[string]int{first.ID: wantFirst, second.ID: 1}
+		for _, agent := range agents {
+			count, ok := want[agent.ID]
+			if !ok {
+				t.Fatalf("unexpected agent %q in requested owner's list", agent.ID)
+			}
+			if agent.PendingCount != count {
+				t.Errorf("agent %q pending count = %d, want %d", agent.ID, agent.PendingCount, count)
+			}
+			delete(want, agent.ID)
+		}
+		if len(want) != 0 {
+			t.Fatalf("missing agents: %v", want)
+		}
+	}
+	assertCounts(2)
+
+	if _, err := pool.Exec(ctx,
+		`UPDATE messages SET status = 'sent' WHERE id = 'msg_pending_count_recent'`,
+	); err != nil {
+		t.Fatalf("resolve pending hold: %v", err)
+	}
+	assertCounts(1)
+}
diff --git a/migrations/133_messages_agent_pending_idx.sql b/migrations/133_messages_agent_pending_idx.sql
new file mode 100644
index 000000000..83d6c68f6
--- /dev/null
+++ b/migrations/133_messages_agent_pending_idx.sql
@@ -0,0 +1,17 @@
+-- 133_messages_agent_pending_idx.sql
+-- e2a:no-transaction
+--
+-- Supports ListAgentsByUser's pending_count: count outbound review holds by
+-- agent without scanning that agent's message history or every agent's holds.
+-- The existing idx_messages_pending_review leads with approval_expires_at for
+-- global expiry sweeps; it cannot directly seek to one agent's holds.
+-- Match the current query's all-time predicate (pending_approval was retired
+-- in 044); do not add a date or deleted_at filter absent from the query.
+--
+-- Build concurrently because messages is a hot table. If an interrupted build
+-- leaves an invalid index, the migration runner refuses to mark this applied.
+-- Recovery: DROP INDEX CONCURRENTLY IF EXISTS idx_messages_agent_pending;
+-- then retry the migration.
+CREATE INDEX CONCURRENTLY IF NOT EXISTS idx_messages_agent_pending
+    ON messages (agent_id)
+    WHERE status = 'pending_review' AND direction = 'outbound';