diff --git a/src/host/index.ts b/src/host/index.ts
index 5be592c..2786c98 100644
--- a/src/host/index.ts
+++ b/src/host/index.ts
@@ -1,2 +1,4 @@
 export { GraphologyHostConfig } from "./graphology.js";
-export type { WorkflowTag, GraphNode, GraphContext, OperationRegistry } from "./graphology.js";
\ No newline at end of file
+export type { WorkflowTag, GraphNode, GraphContext, OperationRegistry as GraphOperationRegistry } from "./graphology.js";
+export { ReactiveHostConfig } from "./reactive.js";
+export type { WorkflowNode, ReactiveContext, OperationRegistry } from "./reactive.js";
\ No newline at end of file
diff --git a/src/host/reactive.ts b/src/host/reactive.ts
index 8cec2e9..dab5d8e 100644
--- a/src/host/reactive.ts
+++ b/src/host/reactive.ts
@@ -1 +1,250 @@
-export {};
\ No newline at end of file
+import { signal, computed } from "@preact/signals-core";
+import type { Signal, ReadonlySignal } from "@preact/signals-core";
+import type { HostConfig } from "@alkdev/ujsx";
+import type { NodeStatus } from "../schema/enums.js";
+import type { CallResult } from "../schema/edge.js";
+import type { EventLogProjection } from "../reactive/workflow.js";
+import type { WorkflowTag } from "./graphology.js";
+
+export interface OperationRegistry {
+  resolve(name: string): unknown;
+}
+
+export interface WorkflowNode {
+  key: string;
+  type: WorkflowTag;
+  status: Signal<NodeStatus>;
+  preconditions: ReadonlySignal<boolean>;
+  blockedByFailure: ReadonlySignal<boolean>;
+  operationId?: string;
+  output?: Signal<unknown>;
+  children: WorkflowNode[];
+}
+
+export interface ReactiveContext {
+  operationRegistry: OperationRegistry;
+  nodes: Map<string, WorkflowNode>;
+  statusSignals: Map<string, Signal<NodeStatus>>;
+  preconditions: Map<string, ReadonlySignal<boolean>>;
+  blockedByFailure: Map<string, ReadonlySignal<boolean>>;
+  resultProjection: EventLogProjection;
+  parentMap: Map<string, string>;
+  siblingMap: Map<string, string[]>;
+  results: Map<string, ReadonlySignal<CallResult | undefined>>;
+  _containerCounter: number;
+}
+
+function collectLeafPredecessors(
+  nodeKey: string,
+  ctx: ReactiveContext,
+): string[] {
+  const parentKey = ctx.parentMap.get(nodeKey);
+  if (!parentKey) return [];
+
+  const parentNode = ctx.nodes.get(parentKey);
+  if (!parentNode) return [];
+
+  const siblings = ctx.siblingMap.get(parentKey);
+  if (!siblings) return [];
+
+  const idx = siblings.indexOf(nodeKey);
+
+  switch (parentNode.type) {
+    case "sequential": {
+      if (idx > 0) {
+        const prevKey = siblings[idx - 1]!;
+        const prevNode = ctx.nodes.get(prevKey);
+        if (prevNode && prevNode.type === "operation") {
+          return [prevKey];
+        }
+        return collectLeafPredecessors(prevKey, ctx);
+      }
+      return collectLeafPredecessors(parentKey, ctx);
+    }
+    case "parallel":
+    case "map":
+    case "conditional": {
+      return collectLeafPredecessors(parentKey, ctx);
+    }
+    default:
+      return [];
+  }
+}
+
+function computePreconditions(
+  node: WorkflowNode,
+  ctx: ReactiveContext,
+): boolean {
+  const predecessors = collectLeafPredecessors(node.key, ctx);
+  if (predecessors.length === 0) return true;
+  return predecessors.every((predKey) => {
+    const predStatus = ctx.statusSignals.get(predKey);
+    if (!predStatus) return true;
+    return predStatus.value === "completed" || predStatus.value === "skipped";
+  });
+}
+
+function computeBlockedByFailure(
+  node: WorkflowNode,
+  ctx: ReactiveContext,
+): boolean {
+  const predecessors = collectLeafPredecessors(node.key, ctx);
+  return predecessors.some((predKey) => {
+    const predStatus = ctx.statusSignals.get(predKey);
+    if (!predStatus) return false;
+    return predStatus.value === "failed" || predStatus.value === "aborted";
+  });
+}
+
+export const ReactiveHostConfig: HostConfig<WorkflowTag, WorkflowNode, ReactiveContext> = {
+  name: "reactive",
+
+  createRootContext(_container, options) {
+    const ctx: ReactiveContext = {
+      operationRegistry: options?.registry as OperationRegistry ?? { resolve: () => undefined },
+      nodes: new Map(),
+      statusSignals: new Map(),
+      preconditions: new Map(),
+      blockedByFailure: new Map(),
+      resultProjection: options?.resultProjection as EventLogProjection ?? {
+        append() {},
+        getStatus: () => "idle" as NodeStatus,
+        getResult: () => undefined,
+        getEvents: () => [],
+      },
+      parentMap: new Map(),
+      siblingMap: new Map(),
+      results: new Map(),
+      _containerCounter: 0,
+    };
+    return ctx;
+  },
+
+  createInstance(tag, props, ctx, parent) {
+    if (tag === "operation") {
+      const key = props.name as string;
+      const status = signal<NodeStatus>("idle");
+
+      const node: WorkflowNode = {
+        key,
+        type: "operation",
+        status,
+        preconditions: computed(() => computePreconditions(node, ctx)),
+        blockedByFailure: computed(() => computeBlockedByFailure(node, ctx)),
+        operationId: key,
+        output: signal<unknown>(undefined),
+        children: [],
+      };
+
+      ctx.nodes.set(key, node);
+      ctx.statusSignals.set(key, status);
+      ctx.preconditions.set(key, node.preconditions);
+      ctx.blockedByFailure.set(key, node.blockedByFailure);
+
+      if (parent) {
+        ctx.parentMap.set(key, parent.key);
+        const siblings = ctx.siblingMap.get(parent.key);
+        if (siblings) {
+          siblings.push(key);
+        } else {
+          ctx.siblingMap.set(parent.key, [key]);
+        }
+      }
+
+      return node;
+    }
+
+    const counter = ctx._containerCounter++;
+    const key = `__${tag}_${counter}`;
+    const status = signal<NodeStatus>("idle");
+
+    const node: WorkflowNode = {
+      key,
+      type: tag,
+      status,
+      preconditions: computed(() => computePreconditions(node, ctx)),
+      blockedByFailure: computed(() => computeBlockedByFailure(node, ctx)),
+      children: [],
+    };
+
+    ctx.nodes.set(key, node);
+    ctx.statusSignals.set(key, status);
+    ctx.preconditions.set(key, node.preconditions);
+    ctx.blockedByFailure.set(key, node.blockedByFailure);
+
+    if (parent) {
+      ctx.parentMap.set(key, parent.key);
+      const siblings = ctx.siblingMap.get(parent.key);
+      if (siblings) {
+        siblings.push(key);
+      } else {
+        ctx.siblingMap.set(parent.key, [key]);
+      }
+    }
+
+    if (!ctx.siblingMap.has(key)) {
+      ctx.siblingMap.set(key, []);
+    }
+
+    return node;
+  },
+
+  createTextInstance(_text, ctx, _parent) {
+    const counter = ctx._containerCounter++;
+    const key = `__text_${counter}`;
+    const status = signal<NodeStatus>("idle");
+    const node: WorkflowNode = {
+      key,
+      type: "sequential" as WorkflowTag,
+      status,
+      preconditions: computed(() => true),
+      blockedByFailure: computed(() => false),
+      children: [],
+    };
+    ctx.nodes.set(key, node);
+    ctx.statusSignals.set(key, status);
+    return node;
+  },
+
+  appendChild(parent, child, _ctx) {
+    if (!parent.children.includes(child)) {
+      parent.children.push(child);
+    }
+  },
+
+  insertBefore(parent, child, before, _ctx) {
+    const idx = parent.children.indexOf(before);
+    if (idx === -1) {
+      parent.children.push(child);
+    } else {
+      if (!parent.children.includes(child)) {
+        parent.children.splice(idx, 0, child);
+      }
+    }
+  },
+
+  removeChild(parent, child, ctx) {
+    parent.children = parent.children.filter((c) => c.key !== child.key);
+
+    const siblings = ctx.siblingMap.get(parent.key);
+    if (siblings) {
+      const idx = siblings.indexOf(child.key);
+      if (idx !== -1) {
+        siblings.splice(idx, 1);
+      }
+    }
+  },
+
+  prepareUpdate() {
+    return null;
+  },
+
+  commitUpdate() {
+  },
+
+  emit() {
+  },
+
+  finalizeInstance(_instance, _ctx) {
+  },
+};
\ No newline at end of file
diff --git a/test/host/reactive.test.ts b/test/host/reactive.test.ts
index 37f88d2..2a5040b 100644
--- a/test/host/reactive.test.ts
+++ b/test/host/reactive.test.ts
@@ -1,7 +1,507 @@
-import { describe, it, expect } from 'vitest';
+import { describe, it, expect } from "vitest";
+import { h, createHostRoot } from "@alkdev/ujsx";
+import { Operation, Sequential, Parallel, Conditional, Map } from "../../src/component/index.js";
+import { ReactiveHostConfig } from "../../src/host/reactive.js";
+import type { WorkflowNode, ReactiveContext } from "../../src/host/reactive.js";
 
-describe('reactive host', () => {
-  it('placeholder', () => {
-    expect(true).toBe(true);
+function renderTemplate(template: ReturnType<typeof h>): ReactiveContext {
+  const root = createHostRoot(ReactiveHostConfig, null);
+  root.render(template);
+  return root.ctx;
+}
+
+describe("ReactiveHostConfig", () => {
+  describe("createRootContext", () => {
+    it("creates fresh ReactiveContext with empty maps", () => {
+      const ctx = ReactiveHostConfig.createRootContext(null);
+      expect(ctx.nodes.size).toBe(0);
+      expect(ctx.statusSignals.size).toBe(0);
+      expect(ctx.parentMap.size).toBe(0);
+      expect(ctx.siblingMap.size).toBe(0);
+    });
+
+    it("accepts options with registry", () => {
+      const registry = { resolve: (name: string) => name };
+      const ctx = ReactiveHostConfig.createRootContext(null, { registry });
+      expect(ctx.operationRegistry).toBe(registry);
+    });
+  });
+
+  describe("createInstance for operation", () => {
+    it("creates WorkflowNode with correct key and type", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "classify" }),
+      );
+
+      const ctx = renderTemplate(template);
+      const node = ctx.nodes.get("classify");
+      expect(node).toBeDefined();
+      expect(node!.key).toBe("classify");
+      expect(node!.type).toBe("operation");
+      expect(node!.operationId).toBe("classify");
+    });
+
+    it("creates WorkflowNode with idle status signal", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "classify" }),
+      );
+
+      const ctx = renderTemplate(template);
+      const node = ctx.nodes.get("classify")!;
+      expect(node.status.value).toBe("idle");
+    });
+
+    it("registers node in context maps", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "classify" }),
+      );
+
+      const ctx = renderTemplate(template);
+      expect(ctx.statusSignals.has("classify")).toBe(true);
+      expect(ctx.preconditions.has("classify")).toBe(true);
+      expect(ctx.blockedByFailure.has("classify")).toBe(true);
+    });
+
+    it("creates output signal for operation nodes", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "classify" }),
+      );
+
+      const ctx = renderTemplate(template);
+      const node = ctx.nodes.get("classify")!;
+      expect(node.output).toBeDefined();
+      expect(node.output!.value).toBeUndefined();
+    });
+  });
+
+  describe("createInstance for structural containers", () => {
+    it("creates WorkflowNode tracking children for Sequential", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "A" }),
+        h(Operation, { name: "B" }),
+      );
+
+      const ctx = renderTemplate(template);
+      const seqNode = ctx.nodes.get("__sequential_0");
+      expect(seqNode).toBeDefined();
+      expect(seqNode!.type).toBe("sequential");
+      expect(seqNode!.children.length).toBe(2);
+    });
+
+    it("creates WorkflowNode for Parallel with children", () => {
+      const template = h(Parallel, {},
+        h(Operation, { name: "A" }),
+        h(Operation, { name: "B" }),
+      );
+
+      const ctx = renderTemplate(template);
+      const parNode = ctx.nodes.get("__parallel_0");
+      expect(parNode).toBeDefined();
+      expect(parNode!.type).toBe("parallel");
+      expect(parNode!.children.length).toBe(2);
+    });
+
+    it("creates WorkflowNode for Conditional with children", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "A" }),
+        h(Conditional, { test: "A" },
+          h(Operation, { name: "B" }),
+        ),
+      );
+
+      const ctx = renderTemplate(template);
+      const condNode = ctx.nodes.get("__conditional_1");
+      expect(condNode).toBeDefined();
+      expect(condNode!.type).toBe("conditional");
+    });
+
+    it("structural containers do not have operationId", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "A" }),
+      );
+
+      const ctx = renderTemplate(template);
+      const seqNode = ctx.nodes.get("__sequential_0")!;
+      expect(seqNode.operationId).toBeUndefined();
+    });
+  });
+
+  describe("signal initial states", () => {
+    it("root operation has preconditions met (no predecessors)", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "A" }),
+        h(Operation, { name: "B" }),
+      );
+
+      const ctx = renderTemplate(template);
+      const nodeA = ctx.nodes.get("A")!;
+      expect(nodeA.preconditions.value).toBe(true);
+    });
+
+    it("second operation in sequential has unmet preconditions", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "A" }),
+        h(Operation, { name: "B" }),
+      );
+
+      const ctx = renderTemplate(template);
+      const nodeB = ctx.nodes.get("B")!;
+      expect(nodeB.preconditions.value).toBe(false);
+    });
+
+    it("parallel children have preconditions met (no inter-child deps)", () => {
+      const template = h(Parallel, {},
+        h(Operation, { name: "A" }),
+        h(Operation, { name: "B" }),
+      );
+
+      const ctx = renderTemplate(template);
+      expect(ctx.nodes.get("A")!.preconditions.value).toBe(true);
+      expect(ctx.nodes.get("B")!.preconditions.value).toBe(true);
+    });
+
+    it("all initial blockedByFailure are false", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "A" }),
+        h(Operation, { name: "B" }),
+      );
+
+      const ctx = renderTemplate(template);
+      expect(ctx.nodes.get("A")!.blockedByFailure.value).toBe(false);
+      expect(ctx.nodes.get("B")!.blockedByFailure.value).toBe(false);
+    });
+  });
+
+  describe("precondition transition on predecessor completion", () => {
+    it("sequential: completing predecessor updates dependent preconditions", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "A" }),
+        h(Operation, { name: "B" }),
+      );
+
+      const ctx = renderTemplate(template);
+      const nodeA = ctx.nodes.get("A")!;
+      const nodeB = ctx.nodes.get("B")!;
+
+      expect(nodeB.preconditions.value).toBe(false);
+
+      nodeA.status.value = "completed";
+
+      expect(nodeB.preconditions.value).toBe(true);
+    });
+
+    it("sequential: skipped predecessor satisfies preconditions", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "A" }),
+        h(Operation, { name: "B" }),
+      );
+
+      const ctx = renderTemplate(template);
+      const nodeA = ctx.nodes.get("A")!;
+
+      nodeA.status.value = "skipped";
+
+      expect(ctx.nodes.get("B")!.preconditions.value).toBe(true);
+    });
+
+    it("sequential chain: A→B→C, completing A then B", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "A" }),
+        h(Operation, { name: "B" }),
+        h(Operation, { name: "C" }),
+      );
+
+      const ctx = renderTemplate(template);
+
+      expect(ctx.nodes.get("B")!.preconditions.value).toBe(false);
+      expect(ctx.nodes.get("C")!.preconditions.value).toBe(false);
+
+      ctx.nodes.get("A")!.status.value = "completed";
+      expect(ctx.nodes.get("B")!.preconditions.value).toBe(true);
+      expect(ctx.nodes.get("C")!.preconditions.value).toBe(false);
+
+      ctx.nodes.get("B")!.status.value = "completed";
+      expect(ctx.nodes.get("C")!.preconditions.value).toBe(true);
+    });
+
+    it("parallel children preconditions independent of each other", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "pre" }),
+        h(Parallel, {},
+          h(Operation, { name: "A" }),
+          h(Operation, { name: "B" }),
+        ),
+      );
+
+      const ctx = renderTemplate(template);
+
+      expect(ctx.nodes.get("A")!.preconditions.value).toBe(false);
+      expect(ctx.nodes.get("B")!.preconditions.value).toBe(false);
+
+      ctx.nodes.get("pre")!.status.value = "completed";
+
+      expect(ctx.nodes.get("A")!.preconditions.value).toBe(true);
+      expect(ctx.nodes.get("B")!.preconditions.value).toBe(true);
+    });
+  });
+
+  describe("failure propagation", () => {
+    it("sequential: failed predecessor causes blockedByFailure to be true", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "A" }),
+        h(Operation, { name: "B" }),
+      );
+
+      const ctx = renderTemplate(template);
+
+      ctx.nodes.get("A")!.status.value = "failed";
+
+      expect(ctx.nodes.get("B")!.blockedByFailure.value).toBe(true);
+    });
+
+    it("sequential: aborted predecessor causes blockedByFailure to be true", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "A" }),
+        h(Operation, { name: "B" }),
+      );
+
+      const ctx = renderTemplate(template);
+
+      ctx.nodes.get("A")!.status.value = "aborted";
+
+      expect(ctx.nodes.get("B")!.blockedByFailure.value).toBe(true);
+    });
+
+    it("parallel siblings are independent for failure propagation", () => {
+      const template = h(Parallel, {},
+        h(Operation, { name: "A" }),
+        h(Operation, { name: "B" }),
+      );
+
+      const ctx = renderTemplate(template);
+
+      ctx.nodes.get("A")!.status.value = "failed";
+
+      expect(ctx.nodes.get("B")!.blockedByFailure.value).toBe(false);
+    });
+
+    it("failed predecessor does not satisfy preconditions", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "A" }),
+        h(Operation, { name: "B" }),
+      );
+
+      const ctx = renderTemplate(template);
+
+      ctx.nodes.get("A")!.status.value = "failed";
+
+      expect(ctx.nodes.get("B")!.preconditions.value).toBe(false);
+    });
+  });
+
+  describe("appendChild", () => {
+    it("appends children to parent's children array", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "A" }),
+        h(Operation, { name: "B" }),
+      );
+
+      const ctx = renderTemplate(template);
+      const seqNode = ctx.nodes.get("__sequential_0")!;
+      expect(seqNode.children.length).toBe(2);
+      expect(seqNode.children[0]!.key).toBe("A");
+      expect(seqNode.children[1]!.key).toBe("B");
+    });
+
+    it("does not duplicate children", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "A" }),
+      );
+
+      const ctx = renderTemplate(template);
+      const seqNode = ctx.nodes.get("__sequential_0")!;
+      const childNode = ctx.nodes.get("A")!;
+      ReactiveHostConfig.appendChild(seqNode, childNode, ctx);
+      expect(seqNode.children.length).toBe(1);
+    });
+  });
+
+  describe("removeChild", () => {
+    it("removes child from parent's children array", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "A" }),
+        h(Operation, { name: "B" }),
+      );
+
+      const ctx = renderTemplate(template);
+      const seqNode = ctx.nodes.get("__sequential_0")!;
+      const childB = ctx.nodes.get("B")!;
+
+      ReactiveHostConfig.removeChild(seqNode, childB, ctx);
+      expect(seqNode.children.length).toBe(1);
+      expect(seqNode.children[0]!.key).toBe("A");
+    });
+
+    it("preconditions auto-reevaluate after removeChild", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "A" }),
+        h(Operation, { name: "B" }),
+        h(Operation, { name: "C" }),
+      );
+
+      const ctx = renderTemplate(template);
+      const seqNode = ctx.nodes.get("__sequential_0")!;
+      const childB = ctx.nodes.get("B")!;
+
+      ctx.nodes.get("A")!.status.value = "completed";
+
+      expect(childB.preconditions.value).toBe(true);
+
+      ReactiveHostConfig.removeChild(seqNode, childB, ctx);
+
+      const childC = ctx.nodes.get("C")!;
+      expect(childC.preconditions.value).toBe(true);
+    });
+  });
+
+  describe("parentMap and siblingMap", () => {
+    it("registers parent-child relationships in parentMap", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "A" }),
+        h(Operation, { name: "B" }),
+      );
+
+      const ctx = renderTemplate(template);
+
+      expect(ctx.parentMap.get("A")).toBe("__sequential_0");
+      expect(ctx.parentMap.get("B")).toBe("__sequential_0");
+    });
+
+    it("registers siblings in siblingMap", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "A" }),
+        h(Operation, { name: "B" }),
+      );
+
+      const ctx = renderTemplate(template);
+
+      const siblings = ctx.siblingMap.get("__sequential_0");
+      expect(siblings).toEqual(["A", "B"]);
+    });
+
+    it("nested structures register correct parent", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "pre" }),
+        h(Parallel, {},
+          h(Operation, { name: "A" }),
+          h(Operation, { name: "B" }),
+        ),
+      );
+
+      const ctx = renderTemplate(template);
+
+      expect(ctx.parentMap.get("pre")).toBe("__sequential_0");
+      expect(ctx.parentMap.get("A")).toBe("__parallel_1");
+      expect(ctx.parentMap.get("B")).toBe("__parallel_1");
+
+      const seqSiblings = ctx.siblingMap.get("__sequential_0");
+      expect(seqSiblings).toEqual(["pre", "__parallel_1"]);
+
+      const parSiblings = ctx.siblingMap.get("__parallel_1");
+      expect(parSiblings).toEqual(["A", "B"]);
+    });
+  });
+
+  describe("Conditional as error boundary", () => {
+    it("conditional node is created with correct type", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "A" }),
+        h(Conditional, { test: "A" },
+          h(Operation, { name: "B" }),
+        ),
+      );
+
+      const ctx = renderTemplate(template);
+
+      const condNode = ctx.nodes.get("__conditional_1");
+      expect(condNode).toBeDefined();
+      expect(condNode!.type).toBe("conditional");
+    });
+
+    it("conditional child has preconditions met (no inter-child ordering)", () => {
+      const template = h(Conditional, { test: "A" },
+        h(Operation, { name: "B" }),
+      );
+
+      const ctx = renderTemplate(template);
+
+      expect(ctx.nodes.get("B")!.preconditions.value).toBe(true);
+    });
+  });
+
+  describe("full template rendering", () => {
+    it("renders a complete pipeline template", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "architect" }),
+        h(Operation, { name: "reviewer" }),
+        h(Parallel, {},
+          h(Operation, { name: "decomposer" }),
+          h(Operation, { name: "specialist" }),
+        ),
+        h(Operation, { name: "synthesizer" }),
+      );
+
+      const ctx = renderTemplate(template);
+
+      expect(ctx.nodes.get("architect")).toBeDefined();
+      expect(ctx.nodes.get("reviewer")).toBeDefined();
+      expect(ctx.nodes.get("decomposer")).toBeDefined();
+      expect(ctx.nodes.get("specialist")).toBeDefined();
+      expect(ctx.nodes.get("synthesizer")).toBeDefined();
+
+      expect(ctx.nodes.get("architect")!.preconditions.value).toBe(true);
+      expect(ctx.nodes.get("reviewer")!.preconditions.value).toBe(false);
+
+      ctx.nodes.get("architect")!.status.value = "completed";
+      expect(ctx.nodes.get("reviewer")!.preconditions.value).toBe(true);
+    });
+
+    it("deeply nested template registers all nodes", () => {
+      const template = h(Sequential, {},
+        h(Parallel, {},
+          h(Sequential, {},
+            h(Operation, { name: "A" }),
+            h(Operation, { name: "B" }),
+          ),
+          h(Operation, { name: "C" }),
+        ),
+      );
+
+      const ctx = renderTemplate(template);
+
+      expect(ctx.nodes.has("A")).toBe(true);
+      expect(ctx.nodes.has("B")).toBe(true);
+      expect(ctx.nodes.has("C")).toBe(true);
+    });
+  });
+
+  describe("shared signal references", () => {
+    it("WorkflowNode.status and statusSignals point to same signal", () => {
+      const template = h(Sequential, {},
+        h(Operation, { name: "A" }),
+      );
+
+      const ctx = renderTemplate(template);
+      const node = ctx.nodes.get("A")!;
+      const statusFromMap = ctx.statusSignals.get("A")!;
+
+      expect(node.status).toBe(statusFromMap);
+
+      statusFromMap.value = "running";
+      expect(node.status.value).toBe("running");
+
+      node.status.value = "completed";
+      expect(statusFromMap.value).toBe("completed");
+    });
   });
 });
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