fix(model-availability): honor connected providers for fallback

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

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

src/agents/utils.test.ts

@@ -228,11 +228,12 @@ describe("createBuiltinAgents without systemDefaultModel", () => {
 })
 
 describe("createBuiltinAgents with requiresModel gating", () => {
-  test("hephaestus is not created when gpt-5.2-codex is unavailable", async () => {
+  test("hephaestus is not created when gpt-5.2-codex is unavailable and provider not connected", async () => {
     // #given
     const fetchSpy = spyOn(shared, "fetchAvailableModels").mockResolvedValue(
       new Set(["anthropic/claude-opus-4-5"])
     )
+    const cacheSpy = spyOn(connectedProvidersCache, "readConnectedProvidersCache").mockReturnValue([])
 
     try {
       // #when
@@ -242,6 +243,7 @@ describe("createBuiltinAgents with requiresModel gating", () => {
       expect(agents.hephaestus).toBeUndefined()
     } finally {
       fetchSpy.mockRestore()
+      cacheSpy.mockRestore()
     }
   })
 
@@ -355,11 +357,12 @@ describe("createBuiltinAgents with requiresAnyModel gating (sisyphus)", () => {
     }
   })
 
-  test("sisyphus is not created when no fallback model is available (unrelated model only)", async () => {
+  test("sisyphus is not created when no fallback model is available and provider not connected", async () => {
     // #given - only openai/gpt-5.2 available, not in sisyphus fallback chain
     const fetchSpy = spyOn(shared, "fetchAvailableModels").mockResolvedValue(
       new Set(["openai/gpt-5.2"])
     )
+    const cacheSpy = spyOn(connectedProvidersCache, "readConnectedProvidersCache").mockReturnValue([])
 
     try {
       // #when
@@ -369,6 +372,7 @@ describe("createBuiltinAgents with requiresAnyModel gating (sisyphus)", () => {
       expect(agents.sisyphus).toBeUndefined()
     } finally {
       fetchSpy.mockRestore()
+      cacheSpy.mockRestore()
     }
   })
 })

src/agents/utils.ts

@@ -395,7 +395,7 @@ export async function createBuiltinAgents(
       !hephaestusRequirement?.requiresModel ||
       hasHephaestusExplicitConfig ||
       isFirstRunNoCache ||
-      (availableModels.size > 0 && isModelAvailable(hephaestusRequirement.requiresModel, availableModels))
+      isAnyFallbackModelAvailable(hephaestusRequirement.fallbackChain, availableModels)
 
     if (hasRequiredModel) {
       let hephaestusResolution = applyModelResolution({

src/shared/agent-tool-restrictions.ts

@@ -22,6 +22,7 @@ const AGENT_RESTRICTIONS: Record<string, Record<string, boolean>> = {
     edit: false,
     task: false,
     delegate_task: false,
+    call_omo_agent: false,
   },
 
   metis: {

src/shared/model-availability.ts

@@ -2,7 +2,7 @@ import { existsSync, readFileSync } from "fs"
 import { join } from "path"
 import { log } from "./logger"
 import { getOpenCodeCacheDir } from "./data-path"
-import { readProviderModelsCache, hasProviderModelsCache } from "./connected-providers-cache"
+import { readProviderModelsCache, hasProviderModelsCache, readConnectedProvidersCache } from "./connected-providers-cache"
 
 /**
  * Fuzzy match a target model name against available models
@@ -278,19 +278,35 @@ export function isAnyFallbackModelAvailable(
 	fallbackChain: Array<{ providers: string[]; model: string }>,
 	availableModels: Set<string>,
 ): boolean {
-	if (availableModels.size === 0) {
-		return false
-	}
-
-	for (const entry of fallbackChain) {
-		const hasAvailableProvider = entry.providers.some((provider) => {
-			return fuzzyMatchModel(entry.model, availableModels, [provider]) !== null
-		})
-		if (hasAvailableProvider) {
-			return true
+	// If we have models, check them first
+	if (availableModels.size > 0) {
+		for (const entry of fallbackChain) {
+			const hasAvailableProvider = entry.providers.some((provider) => {
+				return fuzzyMatchModel(entry.model, availableModels, [provider]) !== null
+			})
+			if (hasAvailableProvider) {
+				return true
+			}
 		}
 	}
-	log("[isAnyFallbackModelAvailable] no model available in chain", { chainLength: fallbackChain.length })
+
+	// Fallback: check if any provider in the chain is connected
+	// This handles race conditions where availableModels is empty or incomplete
+	// but we know the provider is connected.
+	const connectedProviders = readConnectedProvidersCache()
+	if (connectedProviders) {
+		const connectedSet = new Set(connectedProviders)
+		for (const entry of fallbackChain) {
+			if (entry.providers.some((p) => connectedSet.has(p))) {
+				log("[isAnyFallbackModelAvailable] model not in available set, but provider is connected", {
+					model: entry.model,
+					availableCount: availableModels.size,
+				})
+				return true
+			}
+		}
+	}
+
 	return false
 }