feat(agents): simplify GPT detection to name-based check, add hephaestus providers (venice uses gpt-5.3-codex)

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/agents/types.test.ts

@@ -2,11 +2,17 @@ import { describe, test, expect } from "bun:test";
 import { isGptModel, isGeminiModel } from "./types";
 
 describe("isGptModel", () => {
-  test("standard openai provider models", () => {
+  test("standard openai provider gpt models", () => {
     expect(isGptModel("openai/gpt-5.2")).toBe(true);
     expect(isGptModel("openai/gpt-4o")).toBe(true);
-    expect(isGptModel("openai/o1")).toBe(true);
-    expect(isGptModel("openai/o3-mini")).toBe(true);
+  });
+
+  test("o-series models are not gpt by name", () => {
+    expect(isGptModel("openai/o1")).toBe(false);
+    expect(isGptModel("openai/o3-mini")).toBe(false);
+    expect(isGptModel("litellm/o1")).toBe(false);
+    expect(isGptModel("litellm/o3-mini")).toBe(false);
+    expect(isGptModel("litellm/o4-mini")).toBe(false);
   });
 
   test("github copilot gpt models", () => {
@@ -17,9 +23,6 @@ describe("isGptModel", () => {
   test("litellm proxied gpt models", () => {
     expect(isGptModel("litellm/gpt-5.2")).toBe(true);
     expect(isGptModel("litellm/gpt-4o")).toBe(true);
-    expect(isGptModel("litellm/o1")).toBe(true);
-    expect(isGptModel("litellm/o3-mini")).toBe(true);
-    expect(isGptModel("litellm/o4-mini")).toBe(true);
   });
 
   test("other proxied gpt models", () => {
@@ -27,6 +30,11 @@ describe("isGptModel", () => {
     expect(isGptModel("custom-provider/gpt-5.2")).toBe(true);
   });
 
+  test("venice provider gpt models", () => {
+    expect(isGptModel("venice/gpt-5.2")).toBe(true);
+    expect(isGptModel("venice/gpt-4o")).toBe(true);
+  });
+
   test("gpt4 prefix without hyphen (legacy naming)", () => {
     expect(isGptModel("litellm/gpt4o")).toBe(true);
     expect(isGptModel("ollama/gpt4")).toBe(true);

src/agents/types.ts

@@ -70,14 +70,9 @@ function extractModelName(model: string): string {
   return model.includes("/") ? model.split("/").pop() ?? model : model
 }
 
-const GPT_MODEL_PREFIXES = ["gpt-", "gpt4", "o1", "o3", "o4"]
-
 export function isGptModel(model: string): boolean {
-  if (model.startsWith("openai/") || model.startsWith("github-copilot/gpt-"))
-    return true
-
   const modelName = extractModelName(model).toLowerCase()
-  return GPT_MODEL_PREFIXES.some((prefix) => modelName.startsWith(prefix))
+  return modelName.includes("gpt")
 }
 
 const GEMINI_PROVIDERS = ["google/", "google-vertex/"]

src/agents/utils.test.ts

@@ -589,8 +589,8 @@ describe("createBuiltinAgents with requiresProvider gating (hephaestus)", () =>
     }
   })
 
-  test("hephaestus is NOT created when only github-copilot is connected (gpt-5.3-codex unavailable via github-copilot)", async () => {
-    // #given - github-copilot provider has models available, but no cache
+  test("hephaestus IS created when github-copilot is connected with a GPT model", async () => {
+    // #given - github-copilot provider has gpt-5.3-codex available
     const fetchSpy = spyOn(shared, "fetchAvailableModels").mockResolvedValue(
       new Set(["github-copilot/gpt-5.3-codex"])
     )
@@ -600,8 +600,8 @@ describe("createBuiltinAgents with requiresProvider gating (hephaestus)", () =>
       // #when
       const agents = await createBuiltinAgents([], {}, undefined, TEST_DEFAULT_MODEL, undefined, undefined, [], {})
 
-      // #then - hephaestus requires openai/opencode, github-copilot alone is insufficient
-      expect(agents.hephaestus).toBeUndefined()
+      // #then - github-copilot is now a valid provider for hephaestus
+      expect(agents.hephaestus).toBeDefined()
     } finally {
       fetchSpy.mockRestore()
       cacheSpy.mockRestore()

src/shared/model-requirements.test.ts

@@ -168,14 +168,14 @@ describe("AGENT_MODEL_REQUIREMENTS", () => {
     expect(primary.providers[0]).toBe("opencode")
   })
 
-  test("hephaestus requires openai/opencode provider (not github-copilot since gpt-5.3-codex unavailable there)", () => {
+  test("hephaestus supports openai, github-copilot, venice, and opencode providers", () => {
     // #given - hephaestus agent requirement
     const hephaestus = AGENT_MODEL_REQUIREMENTS["hephaestus"]
 
     // #when - accessing hephaestus requirement
-    // #then - requiresProvider is set to openai and opencode only (github-copilot removed)
+    // #then - requiresProvider includes openai, github-copilot, venice, and opencode
     expect(hephaestus).toBeDefined()
-    expect(hephaestus.requiresProvider).toEqual(["openai", "opencode"])
+    expect(hephaestus.requiresProvider).toEqual(["openai", "github-copilot", "venice", "opencode"])
     expect(hephaestus.requiresModel).toBeUndefined()
   })
 

src/shared/model-requirements.ts

@@ -24,9 +24,10 @@ export const AGENT_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
   },
   hephaestus: {
     fallbackChain: [
-      { providers: ["openai", "opencode"], model: "gpt-5.3-codex", variant: "medium" },
+      { providers: ["openai", "venice", "opencode"], model: "gpt-5.3-codex", variant: "medium" },
+      { providers: ["github-copilot"], model: "gpt-5.2", variant: "medium" },
     ],
-    requiresProvider: ["openai", "opencode"],
+    requiresProvider: ["openai", "github-copilot", "venice", "opencode"],
   },
   oracle: {
     fallbackChain: [