experiment(confidence-engine): add openai provider apparatus

tests/llm/provider.test.js

@@ -1,5 +1,9 @@
 import { describe, expect, it, vi } from "vitest";
-import { __resetChatSupportForTests, getProvider } from "@/lib/llm/provider.js";
+import {
+  __resetChatSupportForTests,
+  createOpenAIReconstructionProvider,
+  getProvider,
+} from "@/lib/llm/provider.js";
 
 describe("OllamaLlmProvider chat capability detection", () => {
   it("uses the configured model for the chat probe and keeps the chat path", async () => {
@@ -114,4 +118,65 @@ describe("OllamaLlmProvider chat capability detection", () => {
       else process.env.OLLAMA_BASE_URL = originalBaseUrl;
     }
   });
+});
+
+describe("OpenAI reconstruction provider experiment seam", () => {
+  it("uses the Responses API with the canonical strict reconstruction schema", async () => {
+    const fetchSpy = vi.fn().mockResolvedValue({
+      ok: true,
+      json: async () => ({ output_text: '{"reconstruction":"result"}' }),
+    });
+    const provider = createOpenAIReconstructionProvider({
+      apiKey: "test-key",
+      fetchImpl: fetchSpy,
+    });
+
+    const result = await provider.generateReconstruction(
+      "current reconstruction prompt",
+    );
+    const request = JSON.parse(fetchSpy.mock.calls[0][1].body);
+    const schemaText = JSON.stringify(request.text.format.schema);
+
+    expect(fetchSpy).toHaveBeenCalledWith(
+      "https://api.openai.com/v1/responses",
+      expect.objectContaining({ method: "POST" }),
+    );
+    expect(request).toMatchObject({
+      model: "gpt-5.6-terra",
+      input: "current reconstruction prompt",
+      text: {
+        format: {
+          type: "json_schema",
+          name: "reconstruction",
+          strict: true,
+        },
+      },
+    });
+    expect(schemaText).toContain("relationship");
+    expect(schemaText).toContain("evidenceType");
+    expect(schemaText).toContain("primaryType");
+    expect(schemaText).toContain("secondaryTypes");
+    expect(schemaText).toContain("confidence");
+    expect(schemaText).toContain("importance");
+    expect(result).toEqual({
+      response: { reconstruction: "result" },
+      providerApiPath: "/v1/responses",
+    });
+  });
+
+  it("surfaces Responses API failures without inventing reconstruction content", async () => {
+    const provider = createOpenAIReconstructionProvider({
+      apiKey: "test-key",
+      fetchImpl: vi.fn().mockResolvedValue({
+        ok: false,
+        status: 429,
+        text: async () => "rate limited",
+      }),
+    });
+
+    await expect(provider.generateReconstruction("prompt")).rejects.toMatchObject({
+      providerApiPath: "/v1/responses",
+      message: "OpenAI Responses API returned 429: rate limited",
+    });
+  });
 });