feat(providers): expose gpt-4o on built-in GitHub Copilot (gh) provider

CHANGELOG.md

@@ -40,6 +40,7 @@ _In development — bullets added per PR; finalized at release._
 - **feat(cluster): opt-in memory + Bifrost cluster profiles** — adds opt-in cluster profiles that wire the memory subsystem and the Bifrost Go sidecar into a clustered deployment (follow-up to #3932). ([#4433](https://github.com/diegosouzapw/OmniRoute/pull/4433) — thanks @KooshaPari)
 - **feat(models): opt-in low-noise `/v1/models` catalog mode** — a new opt-in mode trims the `/v1/models` response to a quieter, lower-noise catalog for clients that choke on or don't need the full provider/model list. ([#4427](https://github.com/diegosouzapw/OmniRoute/pull/4427) — thanks @Rahulsharma0810)
 - **feat(ui): expose a `targetFormat` selector in the custom-models form** — the custom-models form now lets you pick the upstream target format explicitly, so a custom model can be pinned to the right wire format instead of relying on inference. ([#4475](https://github.com/diegosouzapw/OmniRoute/pull/4475) — thanks @adivekar-utexas)
+- **feat(providers): expose `gpt-4o` on the built-in GitHub Copilot (`gh`) provider** — GitHub Copilot still serves the original `gpt-4o` chat model via its `/chat/completions` endpoint, but the OmniRoute registry only shipped the GPT-5.x family, so clients that explicitly request `gpt-4o` against `gh` got an unknown-model error. `gpt-4o` is now registered under the `github` provider next to the GPT-5.x lineup (chat/completions, 128k context — no `openai-responses` targetFormat). Ported from [9router#98](https://github.com/decolua/9router/pull/98). (thanks @I3eka)
 
 ### 🐛 Fixed
 

open-sse/config/providers/registry/github/index.ts

@@ -25,6 +25,9 @@ export const githubProvider: RegistryEntry = {
   defaultContextLength: 128000,
   headers: getGitHubCopilotChatHeaders(),
   models: [
+    // 9router#98 — Copilot still serves GPT-4o via chat/completions; keep it
+    // alongside the GPT-5.x family so apps that hard-code `gpt-4o` resolve here.
+    { id: "gpt-4o", name: "GPT-4o", contextLength: 128000 },
     { id: "gpt-5-mini", name: "GPT-5 Mini", targetFormat: "openai-responses" },
     { id: "gpt-5.3-codex", name: "GPT-5.3 Codex", targetFormat: "openai-responses" },
     { id: "gpt-5.4-mini", name: "GPT-5.4 Mini", targetFormat: "openai-responses" },

tests/unit/provider-registry-github-copilot-gpt-4o.test.ts

@@ -0,0 +1,45 @@
+/**
+ * Port of 9router PR #98 — add GPT-4o to GitHub Copilot (`github`/alias `gh`).
+ *
+ * Copilot still serves the original `gpt-4o` chat model via its chat/completions
+ * endpoint. The OmniRoute registry only ships the GPT-5.x family, so apps that
+ * explicitly request `gpt-4o` against the `gh` alias get an "unknown model"
+ * error. Adding the entry restores parity with the upstream Copilot catalog
+ * without disturbing the GPT-5.x / Claude / Gemini lineups already curated.
+ *
+ * GPT-4o is a chat/completions model — it must NOT use `openai-responses`.
+ */
+import test from "node:test";
+import assert from "node:assert/strict";
+
+const { REGISTRY } = await import("../../open-sse/config/providerRegistry.ts");
+const { getModelsByProviderId } = await import("../../open-sse/config/providerModels.ts");
+
+type ModelEntry = { id: string; name?: string; targetFormat?: string; [k: string]: unknown };
+
+function githubModel(id: string): ModelEntry | undefined {
+  const provider = (REGISTRY as Record<string, { models?: ModelEntry[] }>)["github"];
+  return provider?.models?.find((m) => m.id === id);
+}
+
+test("9router#98 github/gpt-4o is registered under the gh provider", () => {
+  const model = githubModel("gpt-4o");
+  assert.ok(model, "gpt-4o must be registered under the github (gh) provider");
+  assert.equal(typeof model?.name, "string");
+});
+
+test("9router#98 github/gpt-4o routes via chat/completions (no openai-responses)", () => {
+  const model = githubModel("gpt-4o");
+  assert.ok(model);
+  assert.notEqual(
+    model.targetFormat,
+    "openai-responses",
+    "GPT-4o on GitHub Copilot is a chat/completions model — Responses API would reject it"
+  );
+});
+
+test("9router#98 getModelsByProviderId(github) exposes gpt-4o", () => {
+  const models = getModelsByProviderId("github") as ModelEntry[];
+  const gpt4o = models.find((m) => m.id === "gpt-4o");
+  assert.ok(gpt4o, "gpt-4o resolvable via getModelsByProviderId(github)");
+});