test: add integration tests for Vercel AI Gateway model resolution

src/cli/__snapshots__/model-fallback.test.ts.snap

@@ -4137,3 +4137,405 @@ exports[`generateModelConfig mixed provider scenarios uses all providers with is
   },
 }
 `;
+
+exports[`generateModelConfig Vercel AI Gateway provider uses vercel/ model strings when only Vercel AI Gateway is available 1`] = `
+{
+  "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-openagent/dev/assets/oh-my-opencode.schema.json",
+  "agents": {
+    "atlas": {
+      "fallback_models": [
+        {
+          "model": "vercel/openai/gpt-5.4",
+          "variant": "medium",
+        },
+      ],
+      "model": "vercel/anthropic/claude-sonnet-4.6",
+    },
+    "explore": {
+      "model": "vercel/anthropic/claude-haiku-4.5",
+    },
+    "hephaestus": {
+      "model": "vercel/openai/gpt-5.4",
+      "variant": "medium",
+    },
+    "librarian": {
+      "model": "vercel/anthropic/claude-haiku-4.5",
+    },
+    "metis": {
+      "fallback_models": [
+        {
+          "model": "vercel/openai/gpt-5.4",
+          "variant": "high",
+        },
+      ],
+      "model": "vercel/anthropic/claude-opus-4.6",
+      "variant": "max",
+    },
+    "momus": {
+      "fallback_models": [
+        {
+          "model": "vercel/anthropic/claude-opus-4.6",
+          "variant": "max",
+        },
+        {
+          "model": "vercel/google/gemini-3.1-pro-preview",
+          "variant": "high",
+        },
+      ],
+      "model": "vercel/openai/gpt-5.4",
+      "variant": "xhigh",
+    },
+    "multimodal-looker": {
+      "fallback_models": [
+        {
+          "model": "vercel/openai/gpt-5-nano",
+        },
+      ],
+      "model": "vercel/openai/gpt-5.4",
+      "variant": "medium",
+    },
+    "oracle": {
+      "fallback_models": [
+        {
+          "model": "vercel/google/gemini-3.1-pro-preview",
+          "variant": "high",
+        },
+        {
+          "model": "vercel/anthropic/claude-opus-4.6",
+          "variant": "max",
+        },
+      ],
+      "model": "vercel/openai/gpt-5.4",
+      "variant": "high",
+    },
+    "prometheus": {
+      "fallback_models": [
+        {
+          "model": "vercel/openai/gpt-5.4",
+          "variant": "high",
+        },
+        {
+          "model": "vercel/google/gemini-3.1-pro-preview",
+        },
+      ],
+      "model": "vercel/anthropic/claude-opus-4.6",
+      "variant": "max",
+    },
+    "sisyphus": {
+      "fallback_models": [
+        {
+          "model": "vercel/openai/gpt-5.4",
+          "variant": "medium",
+        },
+      ],
+      "model": "vercel/anthropic/claude-opus-4.6",
+      "variant": "max",
+    },
+    "sisyphus-junior": {
+      "fallback_models": [
+        {
+          "model": "vercel/openai/gpt-5.4",
+          "variant": "medium",
+        },
+      ],
+      "model": "vercel/anthropic/claude-sonnet-4.6",
+    },
+  },
+  "categories": {
+    "artistry": {
+      "fallback_models": [
+        {
+          "model": "vercel/anthropic/claude-opus-4.6",
+          "variant": "max",
+        },
+        {
+          "model": "vercel/openai/gpt-5.4",
+        },
+      ],
+      "model": "vercel/google/gemini-3.1-pro-preview",
+      "variant": "high",
+    },
+    "deep": {
+      "fallback_models": [
+        {
+          "model": "vercel/anthropic/claude-opus-4.6",
+          "variant": "max",
+        },
+        {
+          "model": "vercel/google/gemini-3.1-pro-preview",
+          "variant": "high",
+        },
+      ],
+      "model": "vercel/openai/gpt-5.4",
+      "variant": "medium",
+    },
+    "quick": {
+      "fallback_models": [
+        {
+          "model": "vercel/anthropic/claude-haiku-4.5",
+        },
+        {
+          "model": "vercel/google/gemini-3-flash-preview",
+        },
+      ],
+      "model": "vercel/openai/gpt-5.4-mini",
+    },
+    "ultrabrain": {
+      "fallback_models": [
+        {
+          "model": "vercel/google/gemini-3.1-pro-preview",
+          "variant": "high",
+        },
+        {
+          "model": "vercel/anthropic/claude-opus-4.6",
+          "variant": "max",
+        },
+      ],
+      "model": "vercel/openai/gpt-5.4",
+      "variant": "xhigh",
+    },
+    "unspecified-high": {
+      "fallback_models": [
+        {
+          "model": "vercel/openai/gpt-5.3-codex",
+          "variant": "medium",
+        },
+        {
+          "model": "vercel/google/gemini-3-flash-preview",
+        },
+      ],
+      "model": "vercel/anthropic/claude-sonnet-4.6",
+    },
+    "unspecified-low": {
+      "fallback_models": [
+        {
+          "model": "vercel/openai/gpt-5.3-codex",
+          "variant": "medium",
+        },
+        {
+          "model": "vercel/google/gemini-3-flash-preview",
+        },
+      ],
+      "model": "vercel/anthropic/claude-sonnet-4.6",
+    },
+    "visual-engineering": {
+      "fallback_models": [
+        {
+          "model": "vercel/anthropic/claude-opus-4.6",
+          "variant": "max",
+        },
+      ],
+      "model": "vercel/google/gemini-3.1-pro-preview",
+      "variant": "high",
+    },
+    "writing": {
+      "fallback_models": [
+        {
+          "model": "vercel/anthropic/claude-sonnet-4.6",
+        },
+      ],
+      "model": "vercel/google/gemini-3-flash-preview",
+    },
+  },
+}
+`;
+
+exports[`generateModelConfig Vercel AI Gateway provider uses vercel/ model strings with isMax20 flag 1`] = `
+{
+  "$schema": "https://raw.githubusercontent.com/code-yeongyu/oh-my-openagent/dev/assets/oh-my-opencode.schema.json",
+  "agents": {
+    "atlas": {
+      "fallback_models": [
+        {
+          "model": "vercel/openai/gpt-5.4",
+          "variant": "medium",
+        },
+      ],
+      "model": "vercel/anthropic/claude-sonnet-4.6",
+    },
+    "explore": {
+      "model": "vercel/anthropic/claude-haiku-4.5",
+    },
+    "hephaestus": {
+      "model": "vercel/openai/gpt-5.4",
+      "variant": "medium",
+    },
+    "librarian": {
+      "model": "vercel/anthropic/claude-haiku-4.5",
+    },
+    "metis": {
+      "fallback_models": [
+        {
+          "model": "vercel/openai/gpt-5.4",
+          "variant": "high",
+        },
+      ],
+      "model": "vercel/anthropic/claude-opus-4.6",
+      "variant": "max",
+    },
+    "momus": {
+      "fallback_models": [
+        {
+          "model": "vercel/anthropic/claude-opus-4.6",
+          "variant": "max",
+        },
+        {
+          "model": "vercel/google/gemini-3.1-pro-preview",
+          "variant": "high",
+        },
+      ],
+      "model": "vercel/openai/gpt-5.4",
+      "variant": "xhigh",
+    },
+    "multimodal-looker": {
+      "fallback_models": [
+        {
+          "model": "vercel/openai/gpt-5-nano",
+        },
+      ],
+      "model": "vercel/openai/gpt-5.4",
+      "variant": "medium",
+    },
+    "oracle": {
+      "fallback_models": [
+        {
+          "model": "vercel/google/gemini-3.1-pro-preview",
+          "variant": "high",
+        },
+        {
+          "model": "vercel/anthropic/claude-opus-4.6",
+          "variant": "max",
+        },
+      ],
+      "model": "vercel/openai/gpt-5.4",
+      "variant": "high",
+    },
+    "prometheus": {
+      "fallback_models": [
+        {
+          "model": "vercel/openai/gpt-5.4",
+          "variant": "high",
+        },
+        {
+          "model": "vercel/google/gemini-3.1-pro-preview",
+        },
+      ],
+      "model": "vercel/anthropic/claude-opus-4.6",
+      "variant": "max",
+    },
+    "sisyphus": {
+      "fallback_models": [
+        {
+          "model": "vercel/openai/gpt-5.4",
+          "variant": "medium",
+        },
+      ],
+      "model": "vercel/anthropic/claude-opus-4.6",
+      "variant": "max",
+    },
+    "sisyphus-junior": {
+      "fallback_models": [
+        {
+          "model": "vercel/openai/gpt-5.4",
+          "variant": "medium",
+        },
+      ],
+      "model": "vercel/anthropic/claude-sonnet-4.6",
+    },
+  },
+  "categories": {
+    "artistry": {
+      "fallback_models": [
+        {
+          "model": "vercel/anthropic/claude-opus-4.6",
+          "variant": "max",
+        },
+        {
+          "model": "vercel/openai/gpt-5.4",
+        },
+      ],
+      "model": "vercel/google/gemini-3.1-pro-preview",
+      "variant": "high",
+    },
+    "deep": {
+      "fallback_models": [
+        {
+          "model": "vercel/anthropic/claude-opus-4.6",
+          "variant": "max",
+        },
+        {
+          "model": "vercel/google/gemini-3.1-pro-preview",
+          "variant": "high",
+        },
+      ],
+      "model": "vercel/openai/gpt-5.4",
+      "variant": "medium",
+    },
+    "quick": {
+      "fallback_models": [
+        {
+          "model": "vercel/anthropic/claude-haiku-4.5",
+        },
+        {
+          "model": "vercel/google/gemini-3-flash-preview",
+        },
+      ],
+      "model": "vercel/openai/gpt-5.4-mini",
+    },
+    "ultrabrain": {
+      "fallback_models": [
+        {
+          "model": "vercel/google/gemini-3.1-pro-preview",
+          "variant": "high",
+        },
+        {
+          "model": "vercel/anthropic/claude-opus-4.6",
+          "variant": "max",
+        },
+      ],
+      "model": "vercel/openai/gpt-5.4",
+      "variant": "xhigh",
+    },
+    "unspecified-high": {
+      "fallback_models": [
+        {
+          "model": "vercel/openai/gpt-5.4",
+          "variant": "high",
+        },
+      ],
+      "model": "vercel/anthropic/claude-opus-4.6",
+      "variant": "max",
+    },
+    "unspecified-low": {
+      "fallback_models": [
+        {
+          "model": "vercel/openai/gpt-5.3-codex",
+          "variant": "medium",
+        },
+        {
+          "model": "vercel/google/gemini-3-flash-preview",
+        },
+      ],
+      "model": "vercel/anthropic/claude-sonnet-4.6",
+    },
+    "visual-engineering": {
+      "fallback_models": [
+        {
+          "model": "vercel/anthropic/claude-opus-4.6",
+          "variant": "max",
+        },
+      ],
+      "model": "vercel/google/gemini-3.1-pro-preview",
+      "variant": "high",
+    },
+    "writing": {
+      "fallback_models": [
+        {
+          "model": "vercel/anthropic/claude-sonnet-4.6",
+        },
+      ],
+      "model": "vercel/google/gemini-3-flash-preview",
+    },
+  },
+}
+`;

src/cli/model-fallback.test.ts

@@ -16,6 +16,7 @@ function createConfig(overrides: Partial<InstallConfig> = {}): InstallConfig {
     hasZaiCodingPlan: false,
     hasKimiForCoding: false,
     hasOpencodeGo: false,
+    hasVercelAiGateway: false,
     ...overrides,
   }
 }
@@ -607,6 +608,74 @@ describe("generateModelConfig", () => {
     })
   })
 
+  describe("Vercel AI Gateway provider", () => {
+    test("uses vercel/ model strings when only Vercel AI Gateway is available", () => {
+      // #given only Vercel AI Gateway is available
+      const config = createConfig({ hasVercelAiGateway: true })
+
+      // #when generateModelConfig is called
+      const result = generateModelConfig(config)
+
+      // #then should use vercel/<sub-provider>/<model> format
+      expect(result).toMatchSnapshot()
+    })
+
+    test("uses vercel/ model strings with isMax20 flag", () => {
+      // #given Vercel AI Gateway is available with Max 20 plan
+      const config = createConfig({ hasVercelAiGateway: true, isMax20: true })
+
+      // #when generateModelConfig is called
+      const result = generateModelConfig(config)
+
+      // #then should use higher capability models via gateway
+      expect(result).toMatchSnapshot()
+    })
+
+    test("explore uses vercel/anthropic/claude-haiku-4.5 when only gateway available", () => {
+      // #given only Vercel AI Gateway is available
+      const config = createConfig({ hasVercelAiGateway: true })
+
+      // #when generateModelConfig is called
+      const result = generateModelConfig(config)
+
+      // #then explore should use gateway-routed claude-haiku
+      expect(result.agents?.explore?.model).toBe("vercel/anthropic/claude-haiku-4.5")
+    })
+
+    test("librarian uses vercel/anthropic/claude-haiku-4.5 when only gateway available", () => {
+      // #given only Vercel AI Gateway is available
+      const config = createConfig({ hasVercelAiGateway: true })
+
+      // #when generateModelConfig is called
+      const result = generateModelConfig(config)
+
+      // #then librarian should use gateway-routed claude-haiku
+      expect(result.agents?.librarian?.model).toBe("vercel/anthropic/claude-haiku-4.5")
+    })
+
+    test("Hephaestus is created when only Vercel AI Gateway is available", () => {
+      // #given only Vercel AI Gateway is available
+      const config = createConfig({ hasVercelAiGateway: true })
+
+      // #when generateModelConfig is called
+      const result = generateModelConfig(config)
+
+      // #then hephaestus should be created with gateway-routed gpt-5.4
+      expect(result.agents?.hephaestus?.model).toBe("vercel/openai/gpt-5.4")
+    })
+
+    test("native providers take priority over gateway", () => {
+      // #given Claude and Vercel AI Gateway are both available
+      const config = createConfig({ hasClaude: true, hasVercelAiGateway: true })
+
+      // #when generateModelConfig is called
+      const result = generateModelConfig(config)
+
+      // #then should prefer native anthropic over gateway
+      expect(result.agents?.sisyphus?.model).toBe("anthropic/claude-opus-4.6")
+    })
+  })
+
   describe("schema URL", () => {
     test("always includes correct schema URL", () => {
       // #given any config