feat(agent): implement phase 2 runtime and inline clarification

tests/lib/agent-models.test.ts

@@ -0,0 +1,61 @@
+import { describe, expect, it } from "vitest";
+
+import {
+  AGENT_MODELS,
+  DEFAULT_AGENT_MODEL_ID,
+  getAgentModel,
+  getAvailableAgentModels,
+  isAgentModelAvailableForTier,
+} from "@/lib/agent-models";
+import { NODE_DEFAULTS } from "@/lib/canvas-utils";
+
+describe("agent models registry", () => {
+  it("contains approved models in stable order", () => {
+    expect(Object.keys(AGENT_MODELS)).toEqual([
+      "openai/gpt-5.4-nano",
+      "openai/gpt-5.4-mini",
+      "openai/gpt-5.4",
+      "openai/gpt-5.4-pro",
+    ]);
+    expect(DEFAULT_AGENT_MODEL_ID).toBe("openai/gpt-5.4-mini");
+  });
+
+  it("resolves model lookup and pricing", () => {
+    expect(getAgentModel("openai/gpt-5.4-nano")?.creditCost).toBe(6);
+    expect(getAgentModel("openai/gpt-5.4-mini")?.creditCost).toBe(15);
+    expect(getAgentModel("openai/gpt-5.4")?.creditCost).toBe(38);
+    expect(getAgentModel("openai/gpt-5.4-pro")?.creditCost).toBe(180);
+    expect(getAgentModel("unknown-model")).toBeUndefined();
+  });
+
+  it("filters models by tier", () => {
+    expect(getAvailableAgentModels("free").map((model) => model.id)).toEqual([]);
+    expect(getAvailableAgentModels("starter").map((model) => model.id)).toEqual([
+      "openai/gpt-5.4-nano",
+      "openai/gpt-5.4-mini",
+      "openai/gpt-5.4",
+    ]);
+    expect(getAvailableAgentModels("max").map((model) => model.id)).toEqual([
+      "openai/gpt-5.4-nano",
+      "openai/gpt-5.4-mini",
+      "openai/gpt-5.4",
+      "openai/gpt-5.4-pro",
+    ]);
+  });
+
+  it("guards access by tier", () => {
+    expect(isAgentModelAvailableForTier("starter", "openai/gpt-5.4")).toBe(true);
+    expect(isAgentModelAvailableForTier("starter", "openai/gpt-5.4-pro")).toBe(false);
+    expect(isAgentModelAvailableForTier("max", "openai/gpt-5.4-pro")).toBe(true);
+  });
+
+  it("uses the registry default in agent node defaults", () => {
+    expect(NODE_DEFAULTS.agent?.data).toMatchObject({
+      templateId: "campaign-distributor",
+      modelId: DEFAULT_AGENT_MODEL_ID,
+      clarificationQuestions: [],
+      clarificationAnswers: {},
+      outputNodeIds: [],
+    });
+  });
+});