diff --git a/docs-site/src/content/docs/reference/configuration/providers.md b/docs-site/src/content/docs/reference/configuration/providers.md
index efaef7729..62203e285 100644
--- a/docs-site/src/content/docs/reference/configuration/providers.md
+++ b/docs-site/src/content/docs/reference/configuration/providers.md
@@ -94,7 +94,7 @@ differing backup and rewrites known legacy namespaced selected ids to bare ids.
 | `modelReasoningEfforts?` | `Record<string, string[]>` | Per-model labels. An empty list hides effort control. As with `reasoningEfforts`, each configured `google`-adapter ladder asserts `thinkingLevel` capability; direct and Vertex non-image requests use the flat Gemini path, while Cloud Code Assist sends it under its request envelope. |
 | `modelSupportsReasoningSummaries?` | `Record<string, boolean>` | Set a model to `false` to stop advertising summaries and strip summary-delivery fields. |
 | `modelReasoningSummaryDelivery?` | `Record<string, "sequential" \| "sequential_cutoff" \| "concurrent" \| "concurrent_cutoff">` | Per-model Responses delivery enum; rewrites an existing delivery field. |
-| `modelAdapters?` | `Record<string, string>` | Per-model `openai-chat` or `openai-responses` wire override for mixed-wire gateways. Explicit entries beat registry defaults; DeepSeek's preset can select native Responses for `deepseek-v4-flash`, and GitHub Copilot declares Responses-only defaults for its GPT-5 family (`gpt-5.3-codex`, `gpt-5.4`, `gpt-5.4-mini`, `gpt-5.5`, `gpt-5.6-luna`, `gpt-5.6-sol`, `gpt-5.6-terra`) because those models reject `/chat/completions` for agent traffic. Models without a built-in default (for example `gpt-5.4-nano`) can be opted in here. Single-wire upstream pins and canonical ChatGPT forward reject overrides. |
+| `modelAdapters?` | `Record<string, string>` | Per-model `openai-chat` or `openai-responses` wire override for mixed-wire gateways. Explicit entries beat registry defaults. The OpenCode Go preset selects Responses for `gpt-5.6-luna` while leaving sibling models on their documented wires; DeepSeek can select native Responses for `deepseek-v4-flash`; and GitHub Copilot declares Responses-only defaults for its GPT-5 family (`gpt-5.3-codex`, `gpt-5.4`, `gpt-5.4-mini`, `gpt-5.5`, `gpt-5.6-luna`, `gpt-5.6-sol`, `gpt-5.6-terra`) because those models reject `/chat/completions` for agent traffic. Models without a built-in default (for example `gpt-5.4-nano`) can be opted in here. Single-wire upstream pins and canonical ChatGPT forward reject overrides. |
 | `modelPreferHostedTools?` | `Record<string,string[]>` | Exact-model opt-in for non-forward Responses gateways that reserve a hosted-tool namespace. Currently accepts only `["image_generation"]`; a matching model must use the `openai-responses` wire and support that hosted tool. It removes colliding client `image_gen` declarations and rewrites their selectors to preserve caller tool choice. For OpenAI API virtual `-pro` models, the selected public ID is matched first and the resolved base wire-model ID is a fallback. `modelAdapters` resolves the public ID first, then the base ID; the second resolution determines the final wire. Other models retain normal alias behavior. |
 | `reasoningEffortMap?` | `Record<string, string>` | Provider-wide wire aliases for reasoning labels. |
 | `modelReasoningEffortMap?` | `Record<string, Record<string, string>>` | Per-model wire aliases for reasoning labels. |
diff --git a/src/providers/registry.ts b/src/providers/registry.ts
index 54c623027..b94483259 100644
--- a/src/providers/registry.ts
+++ b/src/providers/registry.ts
@@ -1177,6 +1177,15 @@ export const PROVIDER_REGISTRY: readonly ProviderRegistryEntry[] = [
     id: "opencode-go", label: "opencode go", adapter: "openai-chat", baseUrl: "https://opencode.ai/zen/go/v1",
     authKind: "key", featured: true, dashboardUrl: "https://opencode.ai/auth", defaultModel: "kimi-k2.7-code",
     jawcodeBundle: "opencode-go", note: "GLM, DeepSeek, Kimi, Qwen, MiMo…",
+    /* [Decision Log]
+    - 목적과 의도: Route GPT 5.6 Luna to the Responses endpoint that OpenCode Go documents for that exact model.
+    - 기존 구현 및 제약 조건: The provider is mixed-wire but its provider-wide `openai-chat` adapter sent Luna to `/chat/completions`; explicit user `modelAdapters` entries must remain authoritative.
+    - 검토한 주요 대안: Change the whole provider to Responses; infer the wire from model-family names; add one registry-only exact-model default.
+    - 선택한 방식: Declare only `gpt-5.6-luna` as `openai-responses` through the existing registry default mechanism.
+    - 다른 대안 대신 이 방식을 선택한 이유: OpenCode Go documents sibling models on Chat or Anthropic endpoints, and an exact registry default preserves both those routes and explicit opt-out precedence.
+    - 장점, 단점 및 영향: Luna reaches `/responses` from every inbound surface without changing siblings; a future upstream endpoint change requires an evidence-backed registry update.
+    */
+    modelWireDefaults: { "gpt-5.6-luna": "openai-responses" },
     modelContextWindows: { "kimi-k3": KIMI_K3_STANDARD_CONTEXT_WINDOW },
     modelInputModalities: { "kimi-k3": ["text", "image"] },
     modelReasoningEfforts: {
diff --git a/structure/04_transports-and-sidecars.md b/structure/04_transports-and-sidecars.md
index e3b052d72..6c88a61d0 100644
--- a/structure/04_transports-and-sidecars.md
+++ b/structure/04_transports-and-sidecars.md
@@ -33,6 +33,29 @@ within their route; neither route falls through to the other. See
 and before the `/v1/*` guard. Unknown `/v1/*` paths return JSON 404 errors instead of falling through
 to GUI static serving.
 
+### Mixed-wire provider defaults
+
+Registry `modelWireDefaults` select an evidence-backed upstream protocol for an exact model without
+changing the provider-wide adapter. Explicit, allowed `modelAdapters` configuration always wins,
+including an entry that opts the model back into the provider-wide wire. Defaults are applied only
+while the configured provider still matches the registry transport, so reusing a preset name for a
+different custom destination does not inherit its upstream assumptions.
+
+OpenCode Go documents `gpt-5.6-luna` on `/zen/go/v1/responses` while sibling models use its Chat or
+Anthropic endpoints. The built-in preset therefore selects `openai-responses` only for Luna and
+keeps the provider-wide `openai-chat` default for other non-pinned models. This endpoint correction
+does not set `modelResponsesUpstreamStreaming`: client `stream: true` remains real upstream
+streaming until a current-runtime reproduction justifies a separate bounded-JSON compatibility
+policy.
+
+[Decision Log]
+- 목적과 의도: Match OpenCode Go's model-specific Luna endpoint without changing sibling model behavior.
+- 기존 구현 및 제약 조건: The preset had one Chat default even though the upstream publishes a mixed Chat, Responses, and Anthropic matrix; operators must retain explicit override precedence.
+- 검토한 주요 대안: Move the whole preset to Responses; infer from the model name; declare one exact registry default; also force bounded JSON from an older conditional terminal report.
+- 선택한 방식: Use one exact Luna wire default and leave upstream streaming unchanged.
+- 다른 대안 대신 이 방식을 선택한 이유: The endpoint mismatch is reproducible from current code and upstream documentation, whereas a current-dev live canary has not established the separate terminal-delivery policy.
+- 장점, 단점 및 영향: Luna reaches its documented endpoint across inbound surfaces and explicit opt-out still works; any future stream workaround remains a separately reviewed compatibility decision.
+
 ### Passthrough SSE stream shapes (#314)
 
 Native passthrough SSE has TWO shapes, selected per request in
diff --git a/tests/opencode-go-luna-wire.test.ts b/tests/opencode-go-luna-wire.test.ts
new file mode 100644
index 000000000..72e383abd
--- /dev/null
+++ b/tests/opencode-go-luna-wire.test.ts
@@ -0,0 +1,85 @@
+/**
+ * OpenCode Go is a mixed-wire provider. Its endpoint matrix assigns GPT 5.6 Luna
+ * to Responses while its provider-wide default and most sibling models use Chat.
+ * These tests protect both the exact-model correction and the explicit override
+ * boundary that lets operators opt out if the upstream changes.
+ */
+import { afterEach, describe, expect, test } from "bun:test";
+import { providerConfigSeed } from "../src/providers/derive";
+import { getProviderRegistryEntry } from "../src/providers/registry";
+import { resolveWireProtocolOverride } from "../src/server/adapter-resolve";
+import { handleResponses } from "../src/server/responses/core";
+import type { OcxConfig, OcxProviderConfig } from "../src/types";
+
+const MODEL = "gpt-5.6-luna";
+
+function opencodeGo(overrides: Partial<OcxProviderConfig> = {}): OcxProviderConfig {
+  const entry = getProviderRegistryEntry("opencode-go");
+  if (!entry) throw new Error("missing opencode-go registry fixture");
+  return { ...providerConfigSeed(entry), apiKey: "test-key", ...overrides };
+}
+
+describe("OpenCode Go GPT 5.6 Luna wire selection (#1482)", () => {
+  test("uses Responses from every inbound surface", () => {
+    for (const inbound of ["responses", "chat", "anthropic"] as const) {
+      expect(resolveWireProtocolOverride("opencode-go", MODEL, opencodeGo(), inbound).adapter)
+        .toBe("openai-responses");
+    }
+  });
+
+  test("an explicit Chat override wins from every inbound surface", () => {
+    const provider = opencodeGo({ modelAdapters: { [MODEL]: "openai-chat" } });
+    for (const inbound of ["responses", "chat", "anthropic"] as const) {
+      expect(resolveWireProtocolOverride("opencode-go", MODEL, provider, inbound).adapter)
+        .toBe("openai-chat");
+    }
+  });
+
+  test("other OpenCode Go models keep their existing wire", () => {
+    for (const inbound of ["responses", "chat", "anthropic"] as const) {
+      expect(resolveWireProtocolOverride("opencode-go", "glm-5.2", opencodeGo(), inbound).adapter)
+        .toBe("openai-chat");
+    }
+  });
+});
+
+describe("OpenCode Go Luna Responses route (#1482)", () => {
+  const originalFetch = globalThis.fetch;
+  afterEach(() => { globalThis.fetch = originalFetch; });
+
+  test("handleResponses sends Luna to the documented /responses endpoint", async () => {
+    const requests: Array<{ url: string; body: Record<string, unknown> }> = [];
+    globalThis.fetch = (async (input: RequestInfo | URL, init?: RequestInit) => {
+      requests.push({
+        url: String(input),
+        body: JSON.parse(String(init?.body ?? "{}")) as Record<string, unknown>,
+      });
+      return Response.json({
+        id: "resp_opencode_go_luna",
+        object: "response",
+        status: "completed",
+        output: [],
+      });
+    }) as typeof fetch;
+
+    const config = {
+      providers: { "opencode-go": opencodeGo() },
+    } as unknown as OcxConfig;
+    const response = await handleResponses(
+      new Request("http://localhost/v1/responses", {
+        method: "POST",
+        headers: { "content-type": "application/json" },
+        body: JSON.stringify({ model: `opencode-go/${MODEL}`, input: "ping", stream: true }),
+      }),
+      config,
+      { model: "", provider: "" },
+      { inboundWire: "responses" },
+    );
+
+    expect(response.status).toBe(200);
+    expect(requests).toHaveLength(1);
+    expect(requests[0]?.url).toBe("https://opencode.ai/zen/go/v1/responses");
+    // The endpoint fix does not silently impose the separate bounded-JSON policy.
+    expect(requests[0]?.body.stream).toBe(true);
+  });
+});