fix(client): resolve hostContext.theme stuck on "light" when dark mode toggled

[mdodell]

Fixes #1982

hostContext.theme and style variables always resolved to "light" even after toggling dark mode in Settings. The global themeMode preference was baked into buildDefaultWorkspaceHostContext, but loadWorkspaceHostContext silently skipped updates when the store was dirty or had a saved config — so the stale value always won.

Removes theme from the default workspace host context so the resolution chain falls through to themeMode directly. The playground theme toggle now updates the global preference instead of patching draftHostContext.

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[chelojimenez]

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[coderabbitai]

Walkthrough

Theme is removed from workspace host-context and client-config builders; buildDefaultWorkspaceHostContext/buildDefaultWorkspaceClientConfig no longer accept or set a theme field. WorkspaceClientConfigSync stops reading theme from the preferences store. HostContextHeader refactors toggle logic to compute a local newTheme and pass it to patchHostContext. Chat/App renderer logic now resolves theme from the host-theme provider (chatboxHostTheme ?? themeMode) instead of draft host context. Tests were updated to reflect that host-context drafts no longer contain theme and theme resolution uses the host-theme provider.

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[Genmin]

Nice fix. I think there is still one saved-config path worth covering before merge: if a workspace already has a saved/draft host context with theme: "light", removing theme from the default host context does not clear that saved value. In the playground, both MCPAppsRenderer and PlaygroundMain still prefer extractHostTheme(draftHostContext) over the shared themeMode, so Settings dark mode can still send/render light for that saved workspace case.

A focused regression would be: set themeMode = "dark", isPlaygroundActive = true, and draftHostContext = { theme: "light" }; assert the MCP Apps bridge hostContext has theme: "dark" and dark SEP variables. The corresponding runtime fix is to resolve MCP Apps/playground rendering theme from the active chat/global preference (chatboxHostTheme ?? themeMode) rather than from draftHostContext.theme, while keeping the other host-context fields unchanged.

[coderabbitai]

🧹 Nitpick comments (1)

mcpjam-inspector/client/src/components/chat-v2/thread/mcp-apps/__tests__/mcp-apps-renderer.test.tsx (1)

384-413: ⚡ Quick win

Strengthen this regression test with dark-token verification.

Lines 399 and 409 assert theme: "dark", but the bug contract also requires dark SEP variables. Please assert hostContext.styles.variables reflects dark-mode tokens in both initialize and update paths.

Proposed test augmentation

+import { getHostStyleOrDefault } from "@/lib/host-styles";
...
   it("resolves theme from host context provider, ignoring draftHostContext.theme", async () => {
     Object.assign(mockPlaygroundStoreState, {
       isPlaygroundActive: true,
     });
     mockPreferencesState.themeMode = "dark";
+    const expectedDarkVariables =
+      getHostStyleOrDefault(mockPreferencesState.hostStyle).resolveStyleVariables(
+        "dark",
+      );
     mockHostContextStoreState.draftHostContext = {
       theme: "light",
     };
...
     expect(appBridgeArgsRef.current?.options?.hostContext?.theme).toBe("dark");
+    expect(
+      appBridgeArgsRef.current?.options?.hostContext?.styles?.variables,
+    ).toMatchObject(expectedDarkVariables);
...
       expect(mockBridge.setHostContext).toHaveBeenLastCalledWith(
         expect.objectContaining({
           theme: "dark",
+          styles: expect.objectContaining({
+            variables: expect.objectContaining(expectedDarkVariables),
+          }),
         }),
       );

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In
`@mcpjam-inspector/client/src/components/chat-v2/thread/mcp-apps/__tests__/mcp-apps-renderer.test.tsx`
around lines 384 - 413, The test currently asserts the theme is "dark" but must
also verify dark-mode SEP variables are present; update the MCPAppsRenderer test
to additionally assert that
appBridgeArgsRef.current?.options?.hostContext?.styles?.variables contains the
expected dark-mode tokens right after render/initialization, and also that
mockBridge.setHostContext was last called with an object whose
hostContext.styles.variables reflect the same dark tokens after triggerReady();
reference the MCPAppsRenderer component, appBridgeArgsRef, mockBridge.connect,
mockBridge.setHostContext, and triggerReady to locate where to add these two
assertions (one for the initial appBridgeArgsRef snapshot and one inside the
expect(mockBridge.setHostContext).toHaveBeenLastCalledWith(...)).

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In
`@mcpjam-inspector/client/src/components/chat-v2/thread/mcp-apps/__tests__/mcp-apps-renderer.test.tsx`:
- Around line 384-413: The test currently asserts the theme is "dark" but must
also verify dark-mode SEP variables are present; update the MCPAppsRenderer test
to additionally assert that
appBridgeArgsRef.current?.options?.hostContext?.styles?.variables contains the
expected dark-mode tokens right after render/initialization, and also that
mockBridge.setHostContext was last called with an object whose
hostContext.styles.variables reflect the same dark tokens after triggerReady();
reference the MCPAppsRenderer component, appBridgeArgsRef, mockBridge.connect,
mockBridge.setHostContext, and triggerReady to locate where to add these two
assertions (one for the initial appBridgeArgsRef snapshot and one inside the
expect(mockBridge.setHostContext).toHaveBeenLastCalledWith(...)).

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

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Run ID: 3911cc3f-f32a-45ac-aba8-465514c7b7e9

📥 Commits

Reviewing files that changed from the base of the PR and between 419b473 and 09fa9e4.

📒 Files selected for processing (5)

• mcpjam-inspector/client/src/components/chat-v2/thread/mcp-apps/__tests__/mcp-apps-renderer.test.tsx
• mcpjam-inspector/client/src/components/chat-v2/thread/mcp-apps/mcp-apps-renderer.tsx
• mcpjam-inspector/client/src/components/shared/HostContextHeader.tsx
• mcpjam-inspector/client/src/components/shared/__tests__/HostContextHeader.test.tsx
• mcpjam-inspector/client/src/components/ui-playground/PlaygroundMain.tsx

✅ Files skipped from review due to trivial changes (3)

• mcpjam-inspector/client/src/components/shared/tests/HostContextHeader.test.tsx
• mcpjam-inspector/client/src/components/ui-playground/PlaygroundMain.tsx
• mcpjam-inspector/client/src/components/shared/HostContextHeader.tsx