diff --git a/docs/guide/installation.md b/docs/guide/installation.md
index c6619e20..eac4c6c6 100644
--- a/docs/guide/installation.md
+++ b/docs/guide/installation.md
@@ -41,19 +41,23 @@ Ask the user these questions to determine CLI options:
      - **not max20** → `--claude=yes`
    - If **no** → `--claude=no`
 
-2. **Will you integrate Gemini models?**
+2. **Do you have an OpenAI/ChatGPT Plus Subscription?**
+   - If **yes** → `--openai=yes` (GPT-5.2 for Oracle agent)
+   - If **no** → `--openai=no` (default)
+
+3. **Will you integrate Gemini models?**
    - If **yes** → `--gemini=yes`
    - If **no** → `--gemini=no`
 
-3. **Do you have a GitHub Copilot Subscription?**
+4. **Do you have a GitHub Copilot Subscription?**
    - If **yes** → `--copilot=yes`
    - If **no** → `--copilot=no`
 
-4. **Do you have access to OpenCode Zen (opencode/ models)?**
+5. **Do you have access to OpenCode Zen (opencode/ models)?**
    - If **yes** → `--opencode-zen=yes`
    - If **no** → `--opencode-zen=no` (default)
 
-5. **Do you have a Z.ai Coding Plan subscription?**
+6. **Do you have a Z.ai Coding Plan subscription?**
    - If **yes** → `--zai-coding-plan=yes`
    - If **no** → `--zai-coding-plan=no` (default)
 
@@ -80,12 +84,13 @@ Spawn a subagent to handle installation and report back - to save context.
 Based on user's answers, run the CLI installer with appropriate flags:
 
 ```bash
-bunx oh-my-opencode install --no-tui --claude=<yes|no|max20> --gemini=<yes|no> --copilot=<yes|no> [--opencode-zen=<yes|no>] [--zai-coding-plan=<yes|no>]
+bunx oh-my-opencode install --no-tui --claude=<yes|no|max20> --gemini=<yes|no> --copilot=<yes|no> [--openai=<yes|no>] [--opencode-zen=<yes|no>] [--zai-coding-plan=<yes|no>]
 ```
 
 **Examples:**
-- User has all native subscriptions: `bunx oh-my-opencode install --no-tui --claude=max20 --gemini=yes --copilot=no`
+- User has all native subscriptions: `bunx oh-my-opencode install --no-tui --claude=max20 --openai=yes --gemini=yes --copilot=no`
 - User has only Claude: `bunx oh-my-opencode install --no-tui --claude=yes --gemini=no --copilot=no`
+- User has Claude + OpenAI: `bunx oh-my-opencode install --no-tui --claude=yes --openai=yes --gemini=no --copilot=no`
 - User has only GitHub Copilot: `bunx oh-my-opencode install --no-tui --claude=no --gemini=no --copilot=yes`
 - User has Z.ai for Librarian: `bunx oh-my-opencode install --no-tui --claude=yes --gemini=no --copilot=no --zai-coding-plan=yes`
 - User has only OpenCode Zen: `bunx oh-my-opencode install --no-tui --claude=no --gemini=no --copilot=no --opencode-zen=yes`
diff --git a/src/cli/config-manager.test.ts b/src/cli/config-manager.test.ts
index a20cb809..504742ed 100644
--- a/src/cli/config-manager.test.ts
+++ b/src/cli/config-manager.test.ts
@@ -201,11 +201,12 @@ describe("config-manager ANTIGRAVITY_PROVIDER_CONFIG", () => {
 })
 
 describe("generateOmoConfig - model fallback system", () => {
-  test("generates native models when Claude available", () => {
-    // #given user has Claude subscription
+  test("generates native sonnet models when Claude standard subscription", () => {
+    // #given user has Claude standard subscription (not max20)
     const config: InstallConfig = {
       hasClaude: true,
       isMax20: false,
+      hasOpenAI: false,
       hasGemini: false,
       hasCopilot: false,
       hasOpencodeZen: false,
@@ -215,17 +216,37 @@ describe("generateOmoConfig - model fallback system", () => {
     // #when generating config
     const result = generateOmoConfig(config)
 
-    // #then should use native anthropic models
+    // #then should use native anthropic sonnet (cost-efficient for standard plan)
     expect(result.$schema).toBe("https://raw.githubusercontent.com/code-yeongyu/oh-my-opencode/master/assets/oh-my-opencode.schema.json")
     expect(result.agents).toBeDefined()
+    expect((result.agents as Record<string, { model: string }>).Sisyphus.model).toBe("anthropic/claude-sonnet-4-5")
+  })
+
+  test("generates native opus models when Claude max20 subscription", () => {
+    // #given user has Claude max20 subscription
+    const config: InstallConfig = {
+      hasClaude: true,
+      isMax20: true,
+      hasOpenAI: false,
+      hasGemini: false,
+      hasCopilot: false,
+      hasOpencodeZen: false,
+      hasZaiCodingPlan: false,
+    }
+
+    // #when generating config
+    const result = generateOmoConfig(config)
+
+    // #then should use native anthropic opus (max power for max20 plan)
     expect((result.agents as Record<string, { model: string }>).Sisyphus.model).toBe("anthropic/claude-opus-4-5")
   })
 
-  test("uses github-copilot fallback when only copilot available", () => {
-    // #given user has only copilot
+  test("uses github-copilot sonnet fallback when only copilot available", () => {
+    // #given user has only copilot (no max plan)
     const config: InstallConfig = {
       hasClaude: false,
       isMax20: false,
+      hasOpenAI: false,
       hasGemini: false,
       hasCopilot: true,
       hasOpencodeZen: false,
@@ -235,8 +256,8 @@ describe("generateOmoConfig - model fallback system", () => {
     // #when generating config
     const result = generateOmoConfig(config)
 
-    // #then should use github-copilot models
-    expect((result.agents as Record<string, { model: string }>).Sisyphus.model).toBe("github-copilot/claude-opus-4.5")
+    // #then should use github-copilot sonnet models
+    expect((result.agents as Record<string, { model: string }>).Sisyphus.model).toBe("github-copilot/claude-sonnet-4.5")
   })
 
   test("uses ultimate fallback when no providers configured", () => {
@@ -244,6 +265,7 @@ describe("generateOmoConfig - model fallback system", () => {
     const config: InstallConfig = {
       hasClaude: false,
       isMax20: false,
+      hasOpenAI: false,
       hasGemini: false,
       hasCopilot: false,
       hasOpencodeZen: false,
@@ -259,10 +281,11 @@ describe("generateOmoConfig - model fallback system", () => {
   })
 
   test("uses zai-coding-plan/glm-4.7 for librarian when Z.ai available", () => {
-    // #given user has Z.ai and Claude
+    // #given user has Z.ai and Claude max20
     const config: InstallConfig = {
       hasClaude: true,
-      isMax20: false,
+      isMax20: true,
+      hasOpenAI: false,
       hasGemini: false,
       hasCopilot: false,
       hasOpencodeZen: false,
@@ -274,7 +297,68 @@ describe("generateOmoConfig - model fallback system", () => {
 
     // #then librarian should use zai-coding-plan/glm-4.7
     expect((result.agents as Record<string, { model: string }>).librarian.model).toBe("zai-coding-plan/glm-4.7")
-    // #then other agents should use native
+    // #then other agents should use native opus (max20 plan)
     expect((result.agents as Record<string, { model: string }>).Sisyphus.model).toBe("anthropic/claude-opus-4-5")
   })
+
+  test("uses native OpenAI models when only ChatGPT available", () => {
+    // #given user has only ChatGPT subscription
+    const config: InstallConfig = {
+      hasClaude: false,
+      isMax20: false,
+      hasOpenAI: true,
+      hasGemini: false,
+      hasCopilot: false,
+      hasOpencodeZen: false,
+      hasZaiCodingPlan: false,
+    }
+
+    // #when generating config
+    const result = generateOmoConfig(config)
+
+    // #then Sisyphus should use native OpenAI (fallback within native tier)
+    expect((result.agents as Record<string, { model: string }>).Sisyphus.model).toBe("openai/gpt-5.2")
+    // #then Oracle should use native OpenAI (primary for ultrabrain)
+    expect((result.agents as Record<string, { model: string }>).oracle.model).toBe("openai/gpt-5.2-codex")
+    // #then multimodal-looker should use native OpenAI (fallback within native tier)
+    expect((result.agents as Record<string, { model: string }>)["multimodal-looker"].model).toBe("openai/gpt-5.2")
+  })
+
+  test("uses haiku for explore when Claude max20", () => {
+    // #given user has Claude max20
+    const config: InstallConfig = {
+      hasClaude: true,
+      isMax20: true,
+      hasOpenAI: false,
+      hasGemini: false,
+      hasCopilot: false,
+      hasOpencodeZen: false,
+      hasZaiCodingPlan: false,
+    }
+
+    // #when generating config
+    const result = generateOmoConfig(config)
+
+    // #then explore should use haiku (max20 plan uses Claude quota)
+    expect((result.agents as Record<string, { model: string }>).explore.model).toBe("anthropic/claude-haiku-4-5")
+  })
+
+  test("uses grok-code for explore when not max20", () => {
+    // #given user has Claude but not max20
+    const config: InstallConfig = {
+      hasClaude: true,
+      isMax20: false,
+      hasOpenAI: false,
+      hasGemini: false,
+      hasCopilot: false,
+      hasOpencodeZen: false,
+      hasZaiCodingPlan: false,
+    }
+
+    // #when generating config
+    const result = generateOmoConfig(config)
+
+    // #then explore should use grok-code (preserve Claude quota)
+    expect((result.agents as Record<string, { model: string }>).explore.model).toBe("opencode/grok-code")
+  })
 })
diff --git a/src/cli/config-manager.ts b/src/cli/config-manager.ts
index 8a9c2e5c..1bfb4e26 100644
--- a/src/cli/config-manager.ts
+++ b/src/cli/config-manager.ts
@@ -575,11 +575,36 @@ export function addProviderConfig(config: InstallConfig): ConfigMergeResult {
   }
 }
 
+function detectProvidersFromOmoConfig(): { hasOpenAI: boolean; hasOpencodeZen: boolean; hasZaiCodingPlan: boolean } {
+  const omoConfigPath = getOmoConfig()
+  if (!existsSync(omoConfigPath)) {
+    return { hasOpenAI: true, hasOpencodeZen: true, hasZaiCodingPlan: false }
+  }
+
+  try {
+    const content = readFileSync(omoConfigPath, "utf-8")
+    const omoConfig = parseJsonc<Record<string, unknown>>(content)
+    if (!omoConfig || typeof omoConfig !== "object") {
+      return { hasOpenAI: true, hasOpencodeZen: true, hasZaiCodingPlan: false }
+    }
+
+    const configStr = JSON.stringify(omoConfig)
+    const hasOpenAI = configStr.includes('"openai/')
+    const hasOpencodeZen = configStr.includes('"opencode/')
+    const hasZaiCodingPlan = configStr.includes('"zai-coding-plan/')
+
+    return { hasOpenAI, hasOpencodeZen, hasZaiCodingPlan }
+  } catch {
+    return { hasOpenAI: true, hasOpencodeZen: true, hasZaiCodingPlan: false }
+  }
+}
+
 export function detectCurrentConfig(): DetectedConfig {
   const result: DetectedConfig = {
     isInstalled: false,
     hasClaude: true,
     isMax20: true,
+    hasOpenAI: true,
     hasGemini: false,
     hasCopilot: false,
     hasOpencodeZen: true,
@@ -607,5 +632,10 @@ export function detectCurrentConfig(): DetectedConfig {
   // Gemini auth plugin detection still works via plugin presence
   result.hasGemini = plugins.some((p) => p.startsWith("opencode-antigravity-auth"))
 
+  const { hasOpenAI, hasOpencodeZen, hasZaiCodingPlan } = detectProvidersFromOmoConfig()
+  result.hasOpenAI = hasOpenAI
+  result.hasOpencodeZen = hasOpencodeZen
+  result.hasZaiCodingPlan = hasZaiCodingPlan
+
   return result
 }
diff --git a/src/cli/index.ts b/src/cli/index.ts
index c554875a..7b415d89 100644
--- a/src/cli/index.ts
+++ b/src/cli/index.ts
@@ -24,6 +24,7 @@ program
   .description("Install and configure oh-my-opencode with interactive setup")
   .option("--no-tui", "Run in non-interactive mode (requires all options)")
   .option("--claude <value>", "Claude subscription: no, yes, max20")
+  .option("--openai <value>", "OpenAI/ChatGPT subscription: no, yes (default: no)")
   .option("--gemini <value>", "Gemini integration: no, yes")
   .option("--copilot <value>", "GitHub Copilot subscription: no, yes")
   .option("--opencode-zen <value>", "OpenCode Zen access: no, yes (default: no)")
@@ -32,11 +33,12 @@ program
   .addHelpText("after", `
 Examples:
   $ bunx oh-my-opencode install
-  $ bunx oh-my-opencode install --no-tui --claude=max20 --gemini=yes --copilot=no
+  $ bunx oh-my-opencode install --no-tui --claude=max20 --openai=yes --gemini=yes --copilot=no
   $ bunx oh-my-opencode install --no-tui --claude=no --gemini=no --copilot=yes --opencode-zen=yes
 
 Model Providers (Priority: Native > Copilot > OpenCode Zen > Z.ai):
   Claude        Native anthropic/ models (Opus, Sonnet, Haiku)
+  OpenAI        Native openai/ models (GPT-5.2 for Oracle)
   Gemini        Native google/ models (Gemini 3 Pro, Flash)
   Copilot       github-copilot/ models (fallback)
   OpenCode Zen  opencode/ models (opencode/claude-opus-4-5, etc.)
@@ -46,6 +48,7 @@ Model Providers (Priority: Native > Copilot > OpenCode Zen > Z.ai):
     const args: InstallArgs = {
       tui: options.tui !== false,
       claude: options.claude,
+      openai: options.openai,
       gemini: options.gemini,
       copilot: options.copilot,
       opencodeZen: options.opencodeZen,
diff --git a/src/cli/install.ts b/src/cli/install.ts
index 8087ff69..30f13ecf 100644
--- a/src/cli/install.ts
+++ b/src/cli/install.ts
@@ -10,6 +10,7 @@ import {
   addProviderConfig,
   detectCurrentConfig,
 } from "./config-manager"
+import { shouldShowChatGPTOnlyWarning } from "./model-fallback"
 import packageJson from "../../package.json" with { type: "json" }
 
 const VERSION = packageJson.version
@@ -39,6 +40,7 @@ function formatConfigSummary(config: InstallConfig): string {
 
   const claudeDetail = config.hasClaude ? (config.isMax20 ? "max20" : "standard") : undefined
   lines.push(formatProvider("Claude", config.hasClaude, claudeDetail))
+  lines.push(formatProvider("OpenAI/ChatGPT", config.hasOpenAI, "GPT-5.2 for Oracle"))
   lines.push(formatProvider("Gemini", config.hasGemini))
   lines.push(formatProvider("GitHub Copilot", config.hasCopilot, "fallback"))
   lines.push(formatProvider("OpenCode Zen", config.hasOpencodeZen, "opencode/ models"))
@@ -127,6 +129,10 @@ function validateNonTuiArgs(args: InstallArgs): { valid: boolean; errors: string
     errors.push(`Invalid --copilot value: ${args.copilot} (expected: no, yes)`)
   }
 
+  if (args.openai !== undefined && !["no", "yes"].includes(args.openai)) {
+    errors.push(`Invalid --openai value: ${args.openai} (expected: no, yes)`)
+  }
+
   if (args.opencodeZen !== undefined && !["no", "yes"].includes(args.opencodeZen)) {
     errors.push(`Invalid --opencode-zen value: ${args.opencodeZen} (expected: no, yes)`)
   }
@@ -142,6 +148,7 @@ function argsToConfig(args: InstallArgs): InstallConfig {
   return {
     hasClaude: args.claude !== "no",
     isMax20: args.claude === "max20",
+    hasOpenAI: args.openai === "yes",
     hasGemini: args.gemini === "yes",
     hasCopilot: args.copilot === "yes",
     hasOpencodeZen: args.opencodeZen === "yes",
@@ -149,7 +156,7 @@ function argsToConfig(args: InstallArgs): InstallConfig {
   }
 }
 
-function detectedToInitialValues(detected: DetectedConfig): { claude: ClaudeSubscription; gemini: BooleanArg; copilot: BooleanArg; opencodeZen: BooleanArg; zaiCodingPlan: BooleanArg } {
+function detectedToInitialValues(detected: DetectedConfig): { claude: ClaudeSubscription; openai: BooleanArg; gemini: BooleanArg; copilot: BooleanArg; opencodeZen: BooleanArg; zaiCodingPlan: BooleanArg } {
   let claude: ClaudeSubscription = "no"
   if (detected.hasClaude) {
     claude = detected.isMax20 ? "max20" : "yes"
@@ -157,6 +164,7 @@ function detectedToInitialValues(detected: DetectedConfig): { claude: ClaudeSubs
 
   return {
     claude,
+    openai: detected.hasOpenAI ? "yes" : "no",
     gemini: detected.hasGemini ? "yes" : "no",
     copilot: detected.hasCopilot ? "yes" : "no",
     opencodeZen: detected.hasOpencodeZen ? "yes" : "no",
@@ -182,6 +190,20 @@ async function runTuiMode(detected: DetectedConfig): Promise<InstallConfig | nul
     return null
   }
 
+  const openai = await p.select({
+    message: "Do you have an OpenAI/ChatGPT Plus subscription?",
+    options: [
+      { value: "no" as const, label: "No", hint: "Oracle will use fallback models" },
+      { value: "yes" as const, label: "Yes", hint: "GPT-5.2 for Oracle (high-IQ debugging)" },
+    ],
+    initialValue: initial.openai,
+  })
+
+  if (p.isCancel(openai)) {
+    p.cancel("Installation cancelled.")
+    return null
+  }
+
   const gemini = await p.select({
     message: "Will you integrate Google Gemini?",
     options: [
@@ -241,6 +263,7 @@ async function runTuiMode(detected: DetectedConfig): Promise<InstallConfig | nul
   return {
     hasClaude: claude !== "no",
     isMax20: claude === "max20",
+    hasOpenAI: openai === "yes",
     hasGemini: gemini === "yes",
     hasCopilot: copilot === "yes",
     hasOpencodeZen: opencodeZen === "yes",
@@ -326,7 +349,21 @@ async function runNonTuiInstall(args: InstallArgs): Promise<number> {
 
   printBox(formatConfigSummary(config), isUpdate ? "Updated Configuration" : "Installation Complete")
 
-  if (!config.hasClaude && !config.hasGemini && !config.hasCopilot) {
+  if (!config.hasClaude) {
+    console.log()
+    console.log(color.bgRed(color.white(color.bold(" ⚠️  CRITICAL WARNING "))))
+    console.log()
+    console.log(color.red(color.bold("  Sisyphus agent is STRONGLY optimized for Claude Opus 4.5.")))
+    console.log(color.red("  Without Claude, you may experience significantly degraded performance:"))
+    console.log(color.dim("    • Reduced orchestration quality"))
+    console.log(color.dim("    • Weaker tool selection and delegation"))
+    console.log(color.dim("    • Less reliable task completion"))
+    console.log()
+    console.log(color.yellow("  Consider subscribing to Claude Pro/Max for the best experience."))
+    console.log()
+  }
+
+  if (!config.hasClaude && !config.hasOpenAI && !config.hasGemini && !config.hasCopilot && !config.hasOpencodeZen) {
     printWarning("No model providers configured. Using opencode/glm-4.7-free as fallback.")
   }
 
@@ -431,7 +468,21 @@ export async function install(args: InstallArgs): Promise<number> {
   }
   s.stop(`Config written to ${color.cyan(omoResult.configPath)}`)
 
-  if (!config.hasClaude && !config.hasGemini && !config.hasCopilot) {
+  if (!config.hasClaude) {
+    console.log()
+    console.log(color.bgRed(color.white(color.bold(" ⚠️  CRITICAL WARNING "))))
+    console.log()
+    console.log(color.red(color.bold("  Sisyphus agent is STRONGLY optimized for Claude Opus 4.5.")))
+    console.log(color.red("  Without Claude, you may experience significantly degraded performance:"))
+    console.log(color.dim("    • Reduced orchestration quality"))
+    console.log(color.dim("    • Weaker tool selection and delegation"))
+    console.log(color.dim("    • Less reliable task completion"))
+    console.log()
+    console.log(color.yellow("  Consider subscribing to Claude Pro/Max for the best experience."))
+    console.log()
+  }
+
+  if (!config.hasClaude && !config.hasOpenAI && !config.hasGemini && !config.hasCopilot && !config.hasOpencodeZen) {
     p.log.warn("No model providers configured. Using opencode/glm-4.7-free as fallback.")
   }
 
diff --git a/src/cli/model-fallback.ts b/src/cli/model-fallback.ts
index 0453a9dc..206a7276 100644
--- a/src/cli/model-fallback.ts
+++ b/src/cli/model-fallback.ts
@@ -1,15 +1,15 @@
 import type { InstallConfig } from "./types"
 
-type ProviderTier = "native" | "github-copilot" | "opencode" | "zai-coding-plan"
+type NativeProvider = "claude" | "openai" | "gemini"
 
 type ModelCapability =
-  | "opus-level"
-  | "sonnet-level"
-  | "haiku-level"
-  | "reasoning"
-  | "codex"
-  | "visual"
-  | "fast"
+  | "unspecified-high"
+  | "unspecified-low"
+  | "quick"
+  | "ultrabrain"
+  | "visual-engineering"
+  | "artistry"
+  | "writing"
   | "glm"
 
 interface ProviderAvailability {
@@ -18,79 +18,127 @@ interface ProviderAvailability {
     openai: boolean
     gemini: boolean
   }
+  opencodeZen: boolean
   copilot: boolean
-  opencode: boolean
   zai: boolean
+  isMaxPlan: boolean
+}
+
+interface AgentConfig {
+  model: string
+  variant?: string
+}
+
+interface CategoryConfig {
+  model: string
+  variant?: string
 }
 
 export interface GeneratedOmoConfig {
   $schema: string
-  agents?: Record<string, { model: string }>
-  categories?: Record<string, { model: string }>
+  agents?: Record<string, AgentConfig>
+  categories?: Record<string, CategoryConfig>
   [key: string]: unknown
 }
 
-const MODEL_CATALOG: Record<ProviderTier, Partial<Record<ModelCapability, string>>> = {
-  native: {
-    "opus-level": "anthropic/claude-opus-4-5",
-    "sonnet-level": "anthropic/claude-sonnet-4-5",
-    "haiku-level": "anthropic/claude-haiku-4-5",
-    reasoning: "openai/gpt-5.2",
-    codex: "openai/gpt-5.2-codex",
-    visual: "google/gemini-3-pro-preview",
-    fast: "google/gemini-3-flash-preview",
-  },
-  "github-copilot": {
-    "opus-level": "github-copilot/claude-opus-4.5",
-    "sonnet-level": "github-copilot/claude-sonnet-4.5",
-    "haiku-level": "github-copilot/claude-haiku-4.5",
-    reasoning: "github-copilot/gpt-5.2",
-    codex: "github-copilot/gpt-5.2-codex",
-    visual: "github-copilot/gemini-3-pro-preview",
-    fast: "github-copilot/grok-code-fast-1",
-  },
-  opencode: {
-    "opus-level": "opencode/claude-opus-4-5",
-    "sonnet-level": "opencode/claude-sonnet-4-5",
-    "haiku-level": "opencode/claude-haiku-4-5",
-    reasoning: "opencode/gpt-5.2",
-    codex: "opencode/gpt-5.2-codex",
-    visual: "opencode/gemini-3-pro",
-    fast: "opencode/grok-code",
-    glm: "opencode/glm-4.7-free",
-  },
-  "zai-coding-plan": {
-    "opus-level": "zai-coding-plan/glm-4.7",
-    "sonnet-level": "zai-coding-plan/glm-4.7",
-    "haiku-level": "zai-coding-plan/glm-4.7-flash",
-    reasoning: "zai-coding-plan/glm-4.7",
-    codex: "zai-coding-plan/glm-4.7",
-    visual: "zai-coding-plan/glm-4.7",
-    fast: "zai-coding-plan/glm-4.7-flash",
-    glm: "zai-coding-plan/glm-4.7",
-  },
+interface NativeFallbackEntry {
+  provider: NativeProvider
+  model: string
 }
 
-const AGENT_REQUIREMENTS: Record<string, ModelCapability> = {
-  Sisyphus: "opus-level",
-  oracle: "reasoning",
-  librarian: "glm",
-  explore: "fast",
-  "multimodal-looker": "visual",
-  "Prometheus (Planner)": "opus-level",
-  "Metis (Plan Consultant)": "sonnet-level",
-  "Momus (Plan Reviewer)": "sonnet-level",
-  Atlas: "opus-level",
+const NATIVE_FALLBACK_CHAINS: Record<ModelCapability, NativeFallbackEntry[]> = {
+  "unspecified-high": [
+    { provider: "claude", model: "anthropic/claude-opus-4-5" },
+    { provider: "openai", model: "openai/gpt-5.2" },
+    { provider: "gemini", model: "google/gemini-3-pro-preview" },
+  ],
+  "unspecified-low": [
+    { provider: "claude", model: "anthropic/claude-sonnet-4-5" },
+    { provider: "openai", model: "openai/gpt-5.2" },
+    { provider: "gemini", model: "google/gemini-3-flash-preview" },
+  ],
+  quick: [
+    { provider: "claude", model: "anthropic/claude-haiku-4-5" },
+    { provider: "openai", model: "openai/gpt-5.1-codex-mini" },
+    { provider: "gemini", model: "google/gemini-3-flash-preview" },
+  ],
+  ultrabrain: [
+    { provider: "openai", model: "openai/gpt-5.2-codex" },
+    { provider: "claude", model: "anthropic/claude-opus-4-5" },
+    { provider: "gemini", model: "google/gemini-3-pro-preview" },
+  ],
+  "visual-engineering": [
+    { provider: "gemini", model: "google/gemini-3-pro-preview" },
+    { provider: "openai", model: "openai/gpt-5.2" },
+    { provider: "claude", model: "anthropic/claude-sonnet-4-5" },
+  ],
+  artistry: [
+    { provider: "gemini", model: "google/gemini-3-pro-preview" },
+    { provider: "openai", model: "openai/gpt-5.2" },
+    { provider: "claude", model: "anthropic/claude-opus-4-5" },
+  ],
+  writing: [
+    { provider: "gemini", model: "google/gemini-3-flash-preview" },
+    { provider: "openai", model: "openai/gpt-5.2" },
+    { provider: "claude", model: "anthropic/claude-sonnet-4-5" },
+  ],
+  glm: [],
 }
 
-const CATEGORY_REQUIREMENTS: Record<string, ModelCapability> = {
-  "visual-engineering": "visual",
-  ultrabrain: "codex",
-  artistry: "visual",
-  quick: "haiku-level",
-  "unspecified-low": "sonnet-level",
-  "unspecified-high": "opus-level",
-  writing: "fast",
+const OPENCODE_ZEN_MODELS: Record<ModelCapability, string> = {
+  "unspecified-high": "opencode/claude-opus-4-5",
+  "unspecified-low": "opencode/claude-sonnet-4-5",
+  quick: "opencode/claude-haiku-4-5",
+  ultrabrain: "opencode/gpt-5.2-codex",
+  "visual-engineering": "opencode/gemini-3-pro",
+  artistry: "opencode/gemini-3-pro",
+  writing: "opencode/gemini-3-flash",
+  glm: "opencode/glm-4.7-free",
+}
+
+const GITHUB_COPILOT_MODELS: Record<ModelCapability, string> = {
+  "unspecified-high": "github-copilot/claude-opus-4.5",
+  "unspecified-low": "github-copilot/claude-sonnet-4.5",
+  quick: "github-copilot/claude-haiku-4.5",
+  ultrabrain: "github-copilot/gpt-5.2-codex",
+  "visual-engineering": "github-copilot/gemini-3-pro-preview",
+  artistry: "github-copilot/gemini-3-pro-preview",
+  writing: "github-copilot/gemini-3-flash-preview",
+  glm: "github-copilot/gpt-5.2",
+}
+
+const ZAI_MODEL = "zai-coding-plan/glm-4.7"
+
+interface AgentRequirement {
+  capability: ModelCapability
+  variant?: string
+}
+
+const AGENT_REQUIREMENTS: Record<string, AgentRequirement> = {
+  Sisyphus: { capability: "unspecified-high" },
+  oracle: { capability: "ultrabrain", variant: "high" },
+  librarian: { capability: "glm" },
+  explore: { capability: "quick" },
+  "multimodal-looker": { capability: "visual-engineering" },
+  "Prometheus (Planner)": { capability: "unspecified-high" },
+  "Metis (Plan Consultant)": { capability: "unspecified-high" },
+  "Momus (Plan Reviewer)": { capability: "ultrabrain", variant: "medium" },
+  Atlas: { capability: "unspecified-high" },
+}
+
+interface CategoryRequirement {
+  capability: ModelCapability
+  variant?: string
+}
+
+const CATEGORY_REQUIREMENTS: Record<string, CategoryRequirement> = {
+  "visual-engineering": { capability: "visual-engineering" },
+  ultrabrain: { capability: "ultrabrain" },
+  artistry: { capability: "artistry", variant: "max" },
+  quick: { capability: "quick" },
+  "unspecified-low": { capability: "unspecified-low" },
+  "unspecified-high": { capability: "unspecified-high" },
+  writing: { capability: "writing" },
 }
 
 const ULTIMATE_FALLBACK = "opencode/glm-4.7-free"
@@ -100,73 +148,51 @@ function toProviderAvailability(config: InstallConfig): ProviderAvailability {
   return {
     native: {
       claude: config.hasClaude,
-      openai: config.hasClaude,
+      openai: config.hasOpenAI,
       gemini: config.hasGemini,
     },
+    opencodeZen: config.hasOpencodeZen,
     copilot: config.hasCopilot,
-    opencode: config.hasOpencodeZen,
     zai: config.hasZaiCodingPlan,
+    isMaxPlan: config.isMax20,
   }
 }
 
-function getProviderPriority(avail: ProviderAvailability): ProviderTier[] {
-  const tiers: ProviderTier[] = []
-
-  if (avail.native.claude || avail.native.openai || avail.native.gemini) {
-    tiers.push("native")
-  }
-  if (avail.copilot) tiers.push("github-copilot")
-  if (avail.opencode) tiers.push("opencode")
-  if (avail.zai) tiers.push("zai-coding-plan")
-
-  return tiers
-}
-
-function hasCapability(
-  tier: ProviderTier,
-  capability: ModelCapability,
-  avail: ProviderAvailability
-): boolean {
-  if (tier === "native") {
-    switch (capability) {
-      case "opus-level":
-      case "sonnet-level":
-      case "haiku-level":
-        return avail.native.claude
-      case "reasoning":
-      case "codex":
-        return avail.native.openai || avail.native.claude
-      case "visual":
-      case "fast":
-        return avail.native.gemini
-      case "glm":
-        return false
-    }
-  }
-  return true
-}
-
 function resolveModel(capability: ModelCapability, avail: ProviderAvailability): string {
-  const tiers = getProviderPriority(avail)
-
-  for (const tier of tiers) {
-    if (hasCapability(tier, capability, avail)) {
-      const model = MODEL_CATALOG[tier][capability]
-      if (model) return model
+  const nativeChain = NATIVE_FALLBACK_CHAINS[capability]
+  for (const entry of nativeChain) {
+    if (avail.native[entry.provider]) {
+      return entry.model
     }
   }
 
+  if (avail.opencodeZen) {
+    return OPENCODE_ZEN_MODELS[capability]
+  }
+
+  if (avail.copilot) {
+    return GITHUB_COPILOT_MODELS[capability]
+  }
+
+  if (avail.zai) {
+    return ZAI_MODEL
+  }
+
   return ULTIMATE_FALLBACK
 }
 
+function resolveClaudeCapability(avail: ProviderAvailability): ModelCapability {
+  return avail.isMaxPlan ? "unspecified-high" : "unspecified-low"
+}
+
 export function generateModelConfig(config: InstallConfig): GeneratedOmoConfig {
   const avail = toProviderAvailability(config)
   const hasAnyProvider =
     avail.native.claude ||
     avail.native.openai ||
     avail.native.gemini ||
+    avail.opencodeZen ||
     avail.copilot ||
-    avail.opencode ||
     avail.zai
 
   if (!hasAnyProvider) {
@@ -181,19 +207,31 @@ export function generateModelConfig(config: InstallConfig): GeneratedOmoConfig {
     }
   }
 
-  const agents: Record<string, { model: string }> = {}
-  const categories: Record<string, { model: string }> = {}
+  const agents: Record<string, AgentConfig> = {}
+  const categories: Record<string, CategoryConfig> = {}
 
-  for (const [role, capability] of Object.entries(AGENT_REQUIREMENTS)) {
+  const claudeCapability = resolveClaudeCapability(avail)
+
+  for (const [role, req] of Object.entries(AGENT_REQUIREMENTS)) {
     if (role === "librarian" && avail.zai) {
-      agents[role] = { model: "zai-coding-plan/glm-4.7" }
+      agents[role] = { model: ZAI_MODEL }
+    } else if (role === "explore") {
+      if (avail.native.claude && avail.isMaxPlan) {
+        agents[role] = { model: "anthropic/claude-haiku-4-5" }
+      } else {
+        agents[role] = { model: "opencode/grok-code" }
+      }
     } else {
-      agents[role] = { model: resolveModel(capability, avail) }
+      const capability = req.capability === "unspecified-high" ? claudeCapability : req.capability
+      const model = resolveModel(capability, avail)
+      agents[role] = req.variant ? { model, variant: req.variant } : { model }
     }
   }
 
-  for (const [cat, capability] of Object.entries(CATEGORY_REQUIREMENTS)) {
-    categories[cat] = { model: resolveModel(capability, avail) }
+  for (const [cat, req] of Object.entries(CATEGORY_REQUIREMENTS)) {
+    const capability = req.capability === "unspecified-high" ? claudeCapability : req.capability
+    const model = resolveModel(capability, avail)
+    categories[cat] = req.variant ? { model, variant: req.variant } : { model }
   }
 
   return {
@@ -202,3 +240,7 @@ export function generateModelConfig(config: InstallConfig): GeneratedOmoConfig {
     categories,
   }
 }
+
+export function shouldShowChatGPTOnlyWarning(config: InstallConfig): boolean {
+  return !config.hasClaude && !config.hasGemini && config.hasOpenAI
+}
diff --git a/src/cli/types.ts b/src/cli/types.ts
index 521b2f48..6825075a 100644
--- a/src/cli/types.ts
+++ b/src/cli/types.ts
@@ -4,6 +4,7 @@ export type BooleanArg = "no" | "yes"
 export interface InstallArgs {
   tui: boolean
   claude?: ClaudeSubscription
+  openai?: BooleanArg
   gemini?: BooleanArg
   copilot?: BooleanArg
   opencodeZen?: BooleanArg
@@ -14,6 +15,7 @@ export interface InstallArgs {
 export interface InstallConfig {
   hasClaude: boolean
   isMax20: boolean
+  hasOpenAI: boolean
   hasGemini: boolean
   hasCopilot: boolean
   hasOpencodeZen: boolean
@@ -30,6 +32,7 @@ export interface DetectedConfig {
   isInstalled: boolean
   hasClaude: boolean
   isMax20: boolean
+  hasOpenAI: boolean
   hasGemini: boolean
   hasCopilot: boolean
   hasOpencodeZen: boolean