fix(opencode-go): route every responses-only model (incl. thinking variants) to /responses

Derive responses-only routing from the model registry's targetFormat instead of hardcoding model checks, and strip thinking suffixes when looking up models in providerModels so variants like gpt-5.6-luna(high) are routed correctly to /responses.

open-sse/config/providerModels.js

@@ -27,11 +27,14 @@ const DOT_VERSION_PROVIDERS = new Set(["kr", "kiro"]);
 // ("claude-sonnet-4-5" ~= "claude-sonnet-4.5"). Other providers use exact match only.
 function findModel(models, modelId, aliasOrId) {
   if (!models) return undefined;
-  const found = models.find(m => m.id === modelId);
+  const baseModelId = typeof modelId === "string"
+    ? modelId.replace(/\([^()]+\)\s*$/, "").trim()
+    : modelId;
+  const found = models.find(m => m.id === modelId || m.id === baseModelId);
   if (found) return found;
   if (!DOT_VERSION_PROVIDERS.has(aliasOrId)) return undefined;
-  const normalized = normalizeModelId(modelId);
-  if (normalized === modelId) return undefined;
+  const normalized = normalizeModelId(baseModelId);
+  if (normalized === baseModelId) return undefined;
   return models.find(m => m.id === normalized);
 }
 

open-sse/executors/opencode-go.js

@@ -1,7 +1,8 @@
 import crypto from "node:crypto";
 import { DefaultExecutor } from "./default.js";
 import { resolveSessionId } from "../utils/sessionManager.js";
-import { isMuseSparkModel } from "../providers/models/helpers.js";
+import { modelTargetFormat } from "../providers/models/schema.js";
+import { getProviderModels } from "../config/providerModels.js";
 import {
   normalizeResponsesInput,
   clampResponsesCallId,
@@ -45,8 +46,11 @@ function baseModelId(model) {
   return String(model || "").replace(/\([^()]+\)\s*$/, "").trim();
 }
 
+// Responses-only per the provider registry (grok-4.6, gpt-5.6-luna, muse-spark, …).
+// Reading the registry keeps this in sync with config — never hardcode model ids here.
 function isResponsesModel(model) {
-  return isMuseSparkModel(baseModelId(model));
+  const entry = getProviderModels("opencode-go").find((m) => m.id === baseModelId(model));
+  return modelTargetFormat(entry) === "openai-responses";
 }
 
 // Flatten Chat Completions tool declarations into the Responses flat shape and

tests/unit/opencode-go-models.test.js

@@ -1,5 +1,5 @@
 import { describe, expect, it } from "vitest";
-import { PROVIDER_MODELS, getModelSupportedFormats } from "../../open-sse/config/providerModels.js";
+import { PROVIDER_MODELS, getModelSupportedFormats, getModelTargetFormat } from "../../open-sse/config/providerModels.js";
 import { PROVIDERS } from "../../open-sse/config/providers.js";
 import { resolveTransport } from "../../open-sse/services/provider.js";
 
@@ -37,6 +37,18 @@ describe("OpenCode Go model catalog", () => {
   });
 });
 
+describe("OpenCode Go thinking-suffix model lookup", () => {
+  it("preserves Responses routing for gpt-5.6-luna thinking variants", () => {
+    expect(getModelSupportedFormats("opencode-go", "gpt-5.6-luna(high)")).toEqual(["openai-responses"]);
+    expect(getModelTargetFormat("opencode-go", "gpt-5.6-luna(high)")).toBe("openai-responses");
+  });
+
+  it("preserves Responses routing for grok-4.6 thinking variants", () => {
+    expect(getModelSupportedFormats("opencode-go", "grok-4.6(high)")).toEqual(["openai-responses"]);
+    expect(getModelTargetFormat("opencode-go", "grok-4.6(high)")).toBe("openai-responses");
+  });
+});
+
 describe("OpenCode Go per-model supportedFormats", () => {
   it("declares [openai, claude] for MiniMax + Qwen models", () => {
     for (const m of CLAUDE_CAPABLE) {

tests/unit/opencode-go-muse-spark-responses.test.js

@@ -48,6 +48,22 @@ describe("ocg/muse-spark-1.3-contributor catalog", () => {
 });
 
 describe("OpenCodeGoExecutor routing + sanitization", () => {
+  it("routes gpt-5.6-luna to /responses", () => {
+    const ex = new OpenCodeGoExecutor();
+    expect(ex.buildUrl("gpt-5.6-luna")).toBe("https://opencode.ai/zen/go/v1/responses");
+    expect(ex.buildUrl("gpt-5.6-luna(high)", true, 0, {
+      runtimeTransport: { baseUrl: "https://opencode.ai/zen/go/v1/chat/completions" },
+    })).toBe("https://opencode.ai/zen/go/v1/responses");
+  });
+
+  it("routes every responses-only registry model (grok-4.6) to /responses", () => {
+    const ex = new OpenCodeGoExecutor();
+    expect(ex.buildUrl("grok-4.6")).toBe("https://opencode.ai/zen/go/v1/responses");
+    expect(ex.buildUrl("grok-4.6(high)", true, 0, {
+      runtimeTransport: { baseUrl: "https://opencode.ai/zen/go/v1/chat/completions" },
+    })).toBe("https://opencode.ai/zen/go/v1/responses");
+  });
+
   it("is wired for opencode-go and routes muse-spark to /responses", () => {
     expect(getExecutor("opencode-go")).toBeInstanceOf(OpenCodeGoExecutor);
     const ex = new OpenCodeGoExecutor();