Fix provider registry refresh race

Author: zzj3720

docs/issue-36-provider-registry-plan.md

@@ -0,0 +1,29 @@
+# Issue 36 Provider Registry Race Plan
+
+## Goal
+
+Prevent Gemini requests from failing with `api("google-generative-ai")` when the first user message and background title generation overlap.
+
+## Current State
+
+`BridgeAIProviderRegistry.registerProviders()` refreshes providers by unregistering the entire `bridge-ai` source and then registering each provider again. The unregister/register sequence contains multiple async actor calls. If another request starts between the clear and the Gemini registration, `APIRegistry` can temporarily have no provider for `google-generative-ai`.
+
+## Proposed Changes
+
+- Add a regression test that keeps probing the Gemini provider while concurrent provider refreshes run.
+- Change `registerProviders()` so normal refreshes overwrite current provider registrations in place instead of clearing the whole source first.
+- Explicitly unregister only optional providers that are no longer valid, such as Azure OpenAI Responses without a valid endpoint.
+
+## If We Do Not Change It
+
+Users can keep seeing intermittent provider-not-found failures and may need to retry messages even with a valid Gemini API key.
+
+## Expected Behavior After Change
+
+Provider settings still refresh, but stable providers such as Gemini remain available throughout concurrent refreshes and background title generation.
+
+## Acceptance Criteria
+
+- A regression test covers concurrent provider refreshes while Gemini remains resolvable.
+- Existing macOS unit tests pass.
+- Manual validation confirms the registry no longer exposes an empty Gemini provider window; full GUI validation is reported separately if environment-limited.

macos/OpenBridge/Agent/BridgeAIProviderRegistry.swift

@@ -3,9 +3,9 @@ import KWWKAI
 
 enum BridgeAIProviderRegistry {
     private static let sourceId = "bridge-ai"
+    private static let azureOpenAIResponsesAPI = "azure-openai-responses"
 
     static func registerProviders() async {
-        await APIRegistry.shared.unregisterSource(sourceId)
         var settings = await BridgeAIProviderSecretStore.readSettings()
         let anthropicConfig = settings[.anthropic]
         if anthropicConfig.authMethod == .oauth {
@@ -24,6 +24,8 @@ enum BridgeAIProviderRegistry {
                 endpoint: azureEndpoint,
                 apiKey: nil
             ), sourceId: sourceId)
+        } else {
+            await APIRegistry.shared.unregister(api: azureOpenAIResponsesAPI)
         }
         var openAIConfig = settings[.openAI]
         if openAIConfig.oauthAccountID == nil {

macos/OpenBridgeUnitTests/Suites/BridgeAIProviderRegistryTests.swift

@@ -0,0 +1,63 @@
+import Foundation
+import KWWKAI
+@testable import OpenBridge
+import Testing
+
+private actor ProviderAvailabilityProbe {
+    private(set) var missingCount = 0
+
+    func recordMissingProvider() {
+        missingCount += 1
+    }
+}
+
+struct BridgeAIProviderRegistryTests {
+    @Test
+    func `concurrent provider refreshes keep Gemini registered`() async throws {
+        let storeDirectory = FileManager.default.temporaryDirectory
+            .appendingPathComponent(UUID().uuidString, isDirectory: true)
+        let storeURL = storeDirectory.appendingPathComponent("secrets.json", isDirectory: false)
+        BridgeAIProviderSecretStore.setStoreURLForTesting(storeURL)
+        defer {
+            BridgeAIProviderSecretStore.setStoreURLForTesting(nil)
+            try? FileManager.default.removeItem(at: storeDirectory)
+        }
+
+        var settings = BridgeAIProviderSettings(selectedModelProvider: "google", selectedModelID: "gemini-2.5-flash")
+        var geminiConfig = settings[.googleGemini]
+        geminiConfig.isEnabled = true
+        geminiConfig.authMethod = .apiKey
+        settings[.googleGemini] = geminiConfig
+        try await BridgeAIProviderSecretStore.saveSecret("test-key", for: .googleGemini, kind: .apiKey)
+        try await BridgeAIProviderSecretStore.saveSettings(settings)
+
+        await BridgeAIProviderRegistry.registerProviders()
+        let initiallyRegistered = await APIRegistry.shared.provider(for: "google-generative-ai")
+        #expect(initiallyRegistered != nil)
+
+        let probe = ProviderAvailabilityProbe()
+        await withTaskGroup(of: Void.self) { group in
+            for _ in 0 ..< 40 {
+                group.addTask {
+                    await BridgeAIProviderRegistry.registerProviders()
+                }
+            }
+
+            for _ in 0 ..< 4 {
+                group.addTask {
+                    for _ in 0 ..< 1000 {
+                        let provider = await APIRegistry.shared.provider(for: "google-generative-ai")
+                        if provider == nil {
+                            await probe.recordMissingProvider()
+                            return
+                        }
+                        await Task.yield()
+                    }
+                }
+            }
+        }
+
+        let missingCount = await probe.missingCount
+        #expect(missingCount == 0)
+    }
+}