diff --git a/internal/plugin/zone_graph_goblin_warrens.go b/internal/plugin/zone_graph_goblin_warrens.go
new file mode 100644
index 0000000..b810b0b
--- /dev/null
+++ b/internal/plugin/zone_graph_goblin_warrens.go
@@ -0,0 +1,53 @@
+package plugin
+
+// Phase G8a — Goblin Warrens branching graph.
+//
+// First non-POC zone. T1 design constraint per
+// gogobee_branching_zones_plan.md §G8: one fork per zone for T1, no
+// secret (the secret pattern is exercised by Crypt of Valdris; Goblin
+// Warrens deliberately validates the bare single-fork shape on a
+// non-POC zone so we can confirm legacy compileLegacyZoneGraph fully
+// hands off to the authored graph end-to-end).
+//
+//   entry → guard_post → fork
+//                          ├──[unlocked]── warband_pit (elite) ──┐
+//                          │                                      ├── warchief_hall → boss
+//                          └──[Perception DC 12]── collapsed_shaft ┘
+//
+// Both branches reach the boss; Perception side is hinted (per plan:
+// "Locked paths should always have a hint — cruel design otherwise").
+
+func zoneGoblinWarrensGraph() ZoneGraph {
+	nodes := []ZoneNode{
+		{NodeID: "goblin_warrens.entry", Kind: NodeKindEntry, IsEntry: true,
+			Label: "Tunnel Mouth", PosX: 0, PosY: 1},
+		{NodeID: "goblin_warrens.guard_post", Kind: NodeKindExploration,
+			Label: "Goblin Guard Post", PosX: 1, PosY: 1},
+		{NodeID: "goblin_warrens.fork", Kind: NodeKindFork,
+			Label: "Cavern Junction", PosX: 2, PosY: 1},
+		{NodeID: "goblin_warrens.warband_pit", Kind: NodeKindElite,
+			Label: "Warband Pit", PosX: 3, PosY: 0},
+		{NodeID: "goblin_warrens.collapsed_shaft", Kind: NodeKindExploration,
+			Label: "Collapsed Shaft", PosX: 3, PosY: 2},
+		{NodeID: "goblin_warrens.warchief_hall", Kind: NodeKindMerge,
+			Label: "Warchief's Hall", PosX: 4, PosY: 1},
+		{NodeID: "goblin_warrens.boss", Kind: NodeKindBoss, IsBoss: true,
+			Label: "Grol's Throne", PosX: 5, PosY: 1},
+	}
+	edges := []ZoneEdge{
+		{From: "goblin_warrens.entry", To: "goblin_warrens.guard_post", Lock: LockNone},
+		{From: "goblin_warrens.guard_post", To: "goblin_warrens.fork", Lock: LockNone},
+		{From: "goblin_warrens.fork", To: "goblin_warrens.warband_pit", Lock: LockNone, Weight: 1},
+		{From: "goblin_warrens.fork", To: "goblin_warrens.collapsed_shaft",
+			Lock: LockPerception, LockData: map[string]any{"dc": 12},
+			Hint: "a muffled scrape behind a heap of fallen timbers", Weight: 2},
+		{From: "goblin_warrens.warband_pit", To: "goblin_warrens.warchief_hall", Lock: LockNone},
+		{From: "goblin_warrens.collapsed_shaft", To: "goblin_warrens.warchief_hall", Lock: LockNone},
+		{From: "goblin_warrens.warchief_hall", To: "goblin_warrens.boss", Lock: LockNone},
+	}
+	return BuildGraph(ZoneGoblinWarrens, nodes, edges)
+}
+
+func init() {
+	registerZoneGraph(zoneGoblinWarrensGraph())
+}
diff --git a/internal/plugin/zone_graph_goblin_warrens_test.go b/internal/plugin/zone_graph_goblin_warrens_test.go
new file mode 100644
index 0000000..fde79cd
--- /dev/null
+++ b/internal/plugin/zone_graph_goblin_warrens_test.go
@@ -0,0 +1,63 @@
+package plugin
+
+import "testing"
+
+func TestGoblinWarrensGraph_Registered(t *testing.T) {
+	g, ok := zoneGraphRegistry[ZoneGoblinWarrens]
+	if !ok {
+		t.Fatal("zoneGoblinWarrensGraph not registered")
+	}
+	if g.Entry != "goblin_warrens.entry" {
+		t.Errorf("entry node = %q, want goblin_warrens.entry", g.Entry)
+	}
+	if g.Boss != "goblin_warrens.boss" {
+		t.Errorf("boss node = %q, want goblin_warrens.boss", g.Boss)
+	}
+	if len(g.Nodes) != 7 {
+		t.Errorf("nodes = %d, want 7", len(g.Nodes))
+	}
+}
+
+func TestGoblinWarrensGraph_BothPathsReachBoss(t *testing.T) {
+	g := zoneGoblinWarrensGraph()
+	if !reachable(g, "goblin_warrens.warband_pit", "goblin_warrens.boss") {
+		t.Error("warband_pit path unreachable to boss")
+	}
+	if !reachable(g, "goblin_warrens.collapsed_shaft", "goblin_warrens.boss") {
+		t.Error("collapsed_shaft path unreachable to boss")
+	}
+}
+
+func TestGoblinWarrensGraph_ForkLayout(t *testing.T) {
+	g := zoneGoblinWarrensGraph()
+	outs := g.outgoingEdges("goblin_warrens.fork")
+	if len(outs) != 2 {
+		t.Fatalf("fork outgoing edges = %d, want 2", len(outs))
+	}
+	// outgoingEdges sorts by weight asc — warband_pit (weight 1) first.
+	if outs[0].To != "goblin_warrens.warband_pit" || outs[0].Lock != LockNone {
+		t.Errorf("first edge = %+v, want warband_pit/LockNone", outs[0])
+	}
+	if outs[1].To != "goblin_warrens.collapsed_shaft" || outs[1].Lock != LockPerception {
+		t.Errorf("second edge = %+v, want collapsed_shaft/LockPerception", outs[1])
+	}
+	if outs[1].Hint == "" {
+		t.Error("collapsed_shaft edge missing player-facing hint (plan §G8: cruel design)")
+	}
+	if dc := lockDataInt(outs[1].LockData, "dc", 0); dc != 12 {
+		t.Errorf("perception DC = %d, want 12", dc)
+	}
+}
+
+// TestGoblinWarrensGraph_NoSecretByDesign locks in the T1 "single fork,
+// no secret" decision recorded in project_phase_G_progress memo. If a
+// later session adds a secret to this zone, this test should be removed
+// or updated deliberately — not silently.
+func TestGoblinWarrensGraph_NoSecretByDesign(t *testing.T) {
+	g := zoneGoblinWarrensGraph()
+	for _, n := range g.Nodes {
+		if n.Kind == NodeKindSecret {
+			t.Errorf("unexpected secret node %q — Goblin Warrens is T1 single-fork by design", n.NodeID)
+		}
+	}
+}