Keep hidden harness defaults in sync

Signed-off-by: kenny lopez <klopez4212@gmail.com>

desktop/src/features/agents/AGENTS.md

@@ -91,7 +91,9 @@ with a TypeScript lookup table or an id comparison in a component.
    from new choices while the raw Rust catalog remains authoritative for
    installation, capabilities, and existing agent configuration. Turning a
    runtime off must not uninstall it, stop it, or invalidate an existing
-   agent that already uses it.
+   agent that already uses it. If the disabled runtime was the saved global
+   default, consumers immediately ignore that preference and the defaults
+   editor persists its visible fallback on the next save.
 10. **The defaults modal is progressively disclosed.** An unset global config
    starts on the Buzz Agent-first deployment fallback and carries that visible
    harness into the next saved edit. The `progressive-defaults` disclosure

desktop/src/features/agents/lib/runtimeVisibilityPreference.test.mjs

@@ -4,6 +4,7 @@ import test from "node:test";
 import {
   ACP_RUNTIME_VISIBILITY_STORAGE_KEY,
   filterEnabledAcpRuntimes,
+  maskDisabledAcpRuntimePreference,
   nextDisabledAcpRuntimeIds,
   parseDisabledAcpRuntimeIds,
   readDisabledAcpRuntimeIds,
@@ -51,3 +52,18 @@ test("stored runtime visibility is read from the versioned device key", () => {
 
   assert.deepEqual(readDisabledAcpRuntimeIds(storage), ["claude"]);
 });
+
+test("a disabled saved runtime is removed from the effective preference", () => {
+  const config = {
+    env_vars: {},
+    provider: null,
+    model: null,
+    preferred_runtime: "Goose",
+  };
+
+  assert.deepEqual(maskDisabledAcpRuntimePreference(config, ["goose"]), {
+    ...config,
+    preferred_runtime: null,
+  });
+  assert.equal(maskDisabledAcpRuntimePreference(config, ["claude"]), config);
+});

desktop/src/features/agents/lib/runtimeVisibilityPreference.ts

@@ -95,6 +95,28 @@ export function filterEnabledAcpRuntimes<T extends { id: string }>(
   );
 }
 
+/**
+ * Prevent a disabled runtime from remaining the effective global preference.
+ *
+ * The persisted config is left untouched until the user next saves defaults;
+ * consumers immediately fall back through the normal runtime selection path.
+ */
+export function maskDisabledAcpRuntimePreference<
+  T extends { preferred_runtime: string | null },
+>(config: T, disabledRuntimeIds: readonly string[]): T {
+  const preferredRuntime = config.preferred_runtime;
+  if (
+    !preferredRuntime ||
+    !disabledRuntimeIds
+      .map(normalizeRuntimeId)
+      .includes(normalizeRuntimeId(preferredRuntime))
+  ) {
+    return config;
+  }
+
+  return { ...config, preferred_runtime: null };
+}
+
 function getDisabledRuntimeIdsSnapshot(): readonly string[] {
   const storage = getLocalStorage();
   if (!storage) return EMPTY_DISABLED_RUNTIME_IDS;

desktop/src/features/agents/ui/AgentDefaultsEditor.tsx

@@ -27,6 +27,7 @@ import {
 import {
   formatRuntimeOptionLabel,
   getDefaultPersonaRuntime,
+  reconcilePreferredRuntimeFallback,
   PERSONA_FIELD_CONTROL_CLASS,
   PERSONA_FIELD_SHELL_CLASS,
   resetConfigForHarnessChange,
@@ -154,16 +155,14 @@ export function AgentDefaultsEditor({
       sortedRuntimes[0]
     );
   }, [config.preferred_runtime, sortedRuntimes]);
-  const renderedConfig = React.useMemo(
-    () =>
-      config.preferred_runtime || !selectedRuntime
-        ? config
-        : { ...config, preferred_runtime: selectedRuntime.id },
-    [config, selectedRuntime],
-  );
   const { data: runtimeFileConfig } = useRuntimeFileConfigQuery(
     selectedRuntime?.id ?? "",
   );
+  const effectiveConfig = React.useMemo(
+    () =>
+      reconcilePreferredRuntimeFallback(config, selectedRuntime?.id ?? null),
+    [config, selectedRuntime],
+  );
   const harnessOptions = React.useMemo(
     () =>
       sortedRuntimes.map((runtime) => ({
@@ -187,7 +186,7 @@ export function AgentDefaultsEditor({
   }
 
   function handleHarnessChange(runtimeId: string) {
-    handleConfigChange(resetConfigForHarnessChange(config, runtimeId));
+    handleConfigChange(resetConfigForHarnessChange(effectiveConfig, runtimeId));
     setConfigIsValid(false);
     setIsCustomModelEditing(false);
     setIsCustomProvider(false);
@@ -196,7 +195,11 @@ export function AgentDefaultsEditor({
   async function handleSave() {
     // Snapshot the config being submitted so we can detect edits that arrive
     // during the IPC round-trip and avoid clobbering the user's newer input.
-    const submittedConfig = config;
+    const draftAtSubmit = configRef.current;
+    const submittedConfig = reconcilePreferredRuntimeFallback(
+      draftAtSubmit,
+      selectedRuntime?.id ?? null,
+    );
     onSavingChange?.(true);
     setSaveState("saving");
     setSaveError(null);
@@ -206,7 +209,7 @@ export function AgentDefaultsEditor({
       // IPC window. If the user edited, keep their newer value and leave dirty=true
       // so they can save again. setDirty(false) runs inside the updater so both
       // state updates batch into the same render (React 18 automatic batching).
-      const savedCurrentDraft = configRef.current === submittedConfig;
+      const savedCurrentDraft = configRef.current === draftAtSubmit;
       setConfig((current) => {
         if (!savedCurrentDraft) {
           // Mid-flight edit detected — do not overwrite newer user input.
@@ -242,7 +245,7 @@ export function AgentDefaultsEditor({
     <AgentConfigFields
       bakedEnv={bakedEnv}
       selectedRuntime={selectedRuntime}
-      config={renderedConfig}
+      config={effectiveConfig}
       disclosure={flatLayout ? "progressive-defaults" : "full"}
       isCustomModelEditing={isCustomModelEditing}
       isCustomProvider={isCustomProvider}

desktop/src/features/agents/ui/agentConfigOptions.test.mjs

@@ -5,6 +5,7 @@ import {
   getDefaultPersonaRuntime,
   getPersonaModelOptions,
   getPersonaProviderOptions,
+  reconcilePreferredRuntimeFallback,
   resetConfigForHarnessChange,
   runtimeSupportsLlmProviderSelection,
 } from "./agentConfigOptions.tsx";
@@ -189,6 +190,23 @@ test("resetConfigForHarnessChange does not carry relay mesh to Goose", () => {
   assert.equal(resetConfigForHarnessChange(config, "goose").provider, null);
 });
 
+test("reconcilePreferredRuntimeFallback updates a hidden saved default", () => {
+  const config = {
+    env_vars: { BUZZ_AGENT_THINKING_EFFORT: "high", SHARED: "kept" },
+    provider: "anthropic",
+    model: "claude-opus",
+    preferred_runtime: "goose",
+  };
+
+  assert.deepEqual(reconcilePreferredRuntimeFallback(config, "buzz-agent"), {
+    env_vars: { SHARED: "kept" },
+    provider: "anthropic",
+    model: null,
+    preferred_runtime: "buzz-agent",
+  });
+  assert.equal(reconcilePreferredRuntimeFallback(config, "goose"), config);
+});
+
 // ── getPersonaModelOptions — codex/claude do not use global provider ──────────
 //
 // The discovery call in AgentDefinitionDialog passes

desktop/src/features/agents/ui/agentConfigOptions.tsx

@@ -198,6 +198,25 @@ export function resetConfigForHarnessChange(
   };
 }
 
+/**
+ * Align a stale or hidden saved preference with the fallback shown by a
+ * runtime selector, clearing values that are not portable across harnesses.
+ */
+export function reconcilePreferredRuntimeFallback(
+  config: GlobalAgentConfig,
+  fallbackRuntimeId: string | null,
+): GlobalAgentConfig {
+  if (
+    !config.preferred_runtime ||
+    !fallbackRuntimeId ||
+    config.preferred_runtime === fallbackRuntimeId
+  ) {
+    return config;
+  }
+
+  return resetConfigForHarnessChange(config, fallbackRuntimeId);
+}
+
 function effectiveModelProviderForOptions(
   runtimeId: string,
   providerId: string | null | undefined,

desktop/src/features/agents/useGlobalAgentConfig.ts

@@ -9,8 +9,14 @@
  * On fetch error the query falls back to EMPTY_CONFIG (safe — the absence of
  * a global config is never an error state for callers).
  */
+import * as React from "react";
+
 import { useQuery } from "@tanstack/react-query";
 
+import {
+  maskDisabledAcpRuntimePreference,
+  useDisabledAcpRuntimeIds,
+} from "@/features/agents/lib/runtimeVisibilityPreference";
 import { getGlobalAgentConfig } from "@/shared/api/tauriGlobalAgentConfig";
 import type { GlobalAgentConfig } from "@/shared/api/types";
 
@@ -27,6 +33,7 @@ export function useGlobalAgentConfig(): {
   globalConfig: GlobalAgentConfig;
   isLoading: boolean;
 } {
+  const disabledRuntimeIds = useDisabledAcpRuntimeIds();
   const { data, isPending } = useQuery({
     queryKey: globalAgentConfigQueryKey,
     queryFn: getGlobalAgentConfig,
@@ -36,9 +43,17 @@ export function useGlobalAgentConfig(): {
     // Never show a stale empty flash while a background refetch runs.
     placeholderData: EMPTY_CONFIG,
   });
+  const globalConfig = React.useMemo(
+    () =>
+      maskDisabledAcpRuntimePreference(
+        data ?? EMPTY_CONFIG,
+        disabledRuntimeIds,
+      ),
+    [data, disabledRuntimeIds],
+  );
 
   return {
-    globalConfig: data ?? EMPTY_CONFIG,
+    globalConfig,
     isLoading: isPending,
   };
 }

desktop/tests/e2e/doctor-states.spec.ts

@@ -240,6 +240,12 @@ test.describe("Doctor panel state screenshots", () => {
         CLAUDE_AVAILABLE_LOGGED_IN,
         BUZZ_AGENT_AVAILABLE,
       ],
+      globalAgentConfig: {
+        env_vars: {},
+        provider: "anthropic",
+        model: "claude-opus",
+        preferred_runtime: "goose",
+      },
     });
 
     await page.goto("/", { waitUntil: "domcontentloaded" });
@@ -251,6 +257,27 @@ test.describe("Doctor panel state screenshots", () => {
     await gooseToggle.click();
     await expect(gooseToggle).not.toBeChecked();
 
+    const defaultHarness = page.getByTestId("global-agent-default-harness");
+    await expect(defaultHarness).toHaveText("Buzz Agent");
+    const provider = page.getByTestId("global-agent-provider");
+    await provider.click();
+    await page.getByTestId("global-agent-provider-option-openai").click();
+    await page.getByRole("button", { name: "Save defaults" }).click();
+    const savedConfig = await page.evaluate(async () =>
+      (
+        window as typeof window & {
+          __BUZZ_E2E_INVOKE_MOCK_COMMAND__?: (
+            command: string,
+            payload: unknown,
+          ) => Promise<unknown>;
+        }
+      ).__BUZZ_E2E_INVOKE_MOCK_COMMAND__?.("get_global_agent_config", null),
+    );
+    expect(savedConfig).toMatchObject({
+      provider: "openai",
+      preferred_runtime: "buzz-agent",
+    });
+
     await page.getByRole("button", { name: "Back to app" }).click();
     await page.getByTestId("open-agents-view").click();
     await page.getByTestId("new-agent-card").click();