Fix hidden agent harness fallbacks

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

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

@@ -8,9 +8,10 @@ import {
 } from "./resolvePersonaRuntime.ts";
 
 function makeRuntime(id, label = `${id} label`) {
-  return { id, label, command: id, avatarUrl: "" };
+  return { id, label, command: id, avatarUrl: "", availability: "available" };
 }
 
+const buzzAgent = makeRuntime("buzz-agent", "Buzz Agent");
 const goose = makeRuntime("goose", "Goose");
 const claude = makeRuntime("claude", "Claude");
 const runtimes = [goose, claude];
@@ -42,6 +43,17 @@ test("resolvePersonaRuntime — hidden defaults are skipped for runtime-less per
   });
 });
 
+test("resolvePersonaRuntime — hidden defaults preserve product fallback order", () => {
+  const result = resolvePersonaRuntime(
+    null,
+    [goose, claude, buzzAgent],
+    goose,
+    false,
+    ["goose"],
+  );
+  assert.equal(result.runtime, buzzAgent);
+});
+
 test("resolvePersonaRuntime — explicitly pinned hidden runtimes remain available", () => {
   const result = resolvePersonaRuntime("goose", runtimes, claude, false, [
     "goose",

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

@@ -149,11 +149,7 @@ function resolveVisibleDefaultRuntime(
     runtimes,
     disabledRuntimeIds,
   );
-  return (
-    visibleRuntimes.find((runtime) => runtime.id === defaultRuntime.id) ??
-    visibleRuntimes[0] ??
-    null
-  );
+  return getDefaultPersonaRuntime(visibleRuntimes, defaultRuntime.id);
 }
 
 /**

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

@@ -35,11 +35,11 @@ import {
 import {
   AUTO_MODEL_DROPDOWN_VALUE,
   AUTO_PROVIDER_DROPDOWN_VALUE,
-  BLOCK_BUILD_HIDDEN_PROVIDER_IDS,
   CUSTOM_PROVIDER_DROPDOWN_VALUE,
   computeLocalModeGate,
   formatRuntimeOptionLabel,
   getDefaultPersonaRuntime,
+  getPersonaHiddenProviderIds,
   getPersonaModelOptions,
   getPersonaProviderOptions,
   getRuntimePersonaModelOptions,
@@ -528,17 +528,12 @@ export function AgentDefinitionDialog({
     modelFieldVisible,
     provider: effectiveProvider,
   });
-  // On internal Block builds, BUZZ_AGENT_PROVIDER is baked in and a boot
-  // migration rewrites any persisted Databricks v1 values → v2. Hide the v1
-  // option there so it is not offered for new selections. OSS builds have no
-  // baked provider, so v1 remains visible.
-  const hideProviderIds = React.useMemo(
-    () =>
-      (bakedEnvKeys ?? []).includes("BUZZ_AGENT_PROVIDER")
-        ? BLOCK_BUILD_HIDDEN_PROVIDER_IDS
-        : new Set<string>(),
-    [bakedEnvKeys],
-  );
+  const hideProviderIds = getPersonaHiddenProviderIds({
+    bakedEnvKeys: bakedEnvKeys ?? [],
+    selectableRuntimes,
+    currentRuntimeId: runtime,
+    preserveCurrentRuntime: !isCreateMode,
+  });
   const providerOptions = getPersonaProviderOptions(
     trimmedProvider,
     runtime,

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

@@ -27,12 +27,13 @@ import { setManagedAgentAutoRestart } from "@/shared/api/tauriManagedAgents";
 import { EditAgentAdvancedFields } from "./EditAgentAdvancedFields";
 import {
   AUTO_PROVIDER_DROPDOWN_VALUE,
-  BLOCK_BUILD_HIDDEN_PROVIDER_IDS,
   CUSTOM_PROVIDER_DROPDOWN_VALUE,
   formatRuntimeOptionLabel,
   getDefaultLlmModelLabel,
   getDefaultPersonaRuntime,
+  getPersonaHiddenProviderIds,
   getPersonaProviderOptions,
+  getProviderApiKeyEnvVar,
   isMissingRequiredDropdownField,
   NO_RUNTIME_DROPDOWN_VALUE,
   PERSONA_FIELD_CONTROL_CLASS,
@@ -75,7 +76,6 @@ import {
   getBakedModelInheritLabel,
   getBakedProviderInheritLabel,
 } from "./bakedEnvHelpers";
-import { getProviderApiKeyEnvVar } from "./agentConfigOptions";
 import { useAgentDialogDefaults } from "./useAgentDialogDefaults";
 import { AgentAiDefaultsNotice } from "./AgentAiDefaults";
 import { AgentDefaultsDialog } from "./AgentDefaultsDialog";
@@ -790,13 +790,12 @@ export function AgentInstanceEditDialog({
 
   // Provider field derived state
   const trimmedProvider = provider.trim();
-  const hideProviderIds = React.useMemo(
-    () =>
-      (bakedEnvKeys ?? []).includes("BUZZ_AGENT_PROVIDER")
-        ? BLOCK_BUILD_HIDDEN_PROVIDER_IDS
-        : new Set<string>(),
-    [bakedEnvKeys],
-  );
+  const hideProviderIds = getPersonaHiddenProviderIds({
+    bakedEnvKeys: bakedEnvKeys ?? [],
+    selectableRuntimes,
+    currentRuntimeId: selectedRuntimeId,
+    preserveCurrentRuntime: true,
+  });
   const providerOptions = getPersonaProviderOptions(
     trimmedProvider,
     selectedRuntime?.id ?? "",

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

@@ -3,6 +3,7 @@ import test from "node:test";
 
 import {
   getDefaultPersonaRuntime,
+  getPersonaHiddenProviderIds,
   getPersonaModelOptions,
   getPersonaProviderOptions,
   reconcilePreferredRuntimeFallback,
@@ -75,6 +76,32 @@ test("getPersonaProviderOptions appends (current) tail for an unknown saved prov
   assert.equal(tail?.label, "my-custom-llm (current)");
 });
 
+test("hidden Buzz Agent suppresses shared compute for new selections", () => {
+  const hidden = getPersonaHiddenProviderIds({
+    bakedEnvKeys: [],
+    selectableRuntimes: [makeRuntime("goose")],
+    currentRuntimeId: "goose",
+    preserveCurrentRuntime: false,
+  });
+  const ids = getPersonaProviderOptions("", "goose", "", hidden).map(
+    (option) => option.id,
+  );
+  assert.ok(!ids.includes("relay-mesh"));
+});
+
+test("an existing hidden Buzz Agent keeps its shared compute provider", () => {
+  const hidden = getPersonaHiddenProviderIds({
+    bakedEnvKeys: [],
+    selectableRuntimes: [makeRuntime("goose")],
+    currentRuntimeId: "buzz-agent",
+    preserveCurrentRuntime: true,
+  });
+  const ids = getPersonaProviderOptions("", "buzz-agent", "", hidden).map(
+    (option) => option.id,
+  );
+  assert.ok(ids.includes("relay-mesh"));
+});
+
 // ── getDefaultPersonaRuntime — buzz-agent first ───────────────────────────────
 
 test("getDefaultPersonaRuntime honors an available global preference", () => {

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

@@ -14,15 +14,34 @@ export { getDefaultPersonaRuntime } from "../lib/resolvePersonaRuntime";
  * offering it for new selections would create a regression path.
  * OSS builds pass an empty `Set` so v1 remains visible.
  *
- * All three dialog sites that show a provider picker import this constant —
- * `AgentDefinitionDialog`, `AgentInstanceEditDialog`, and
- * `AgentDefaultsSettingsCard` — making it the single source of truth for
- * which provider ids to suppress on Block builds.
+ * Provider pickers consume this directly or through
+ * `getPersonaHiddenProviderIds`, keeping one source of truth for Block builds.
  */
 export const BLOCK_BUILD_HIDDEN_PROVIDER_IDS: ReadonlySet<string> = new Set([
   "databricks",
 ]);
 
+export function getPersonaHiddenProviderIds({
+  bakedEnvKeys,
+  selectableRuntimes,
+  currentRuntimeId,
+  preserveCurrentRuntime,
+}: {
+  bakedEnvKeys: readonly string[];
+  selectableRuntimes: readonly Pick<AcpRuntimeCatalogEntry, "id">[];
+  currentRuntimeId: string;
+  preserveCurrentRuntime: boolean;
+}): ReadonlySet<string> {
+  const hidden = bakedEnvKeys.includes("BUZZ_AGENT_PROVIDER")
+    ? new Set(BLOCK_BUILD_HIDDEN_PROVIDER_IDS)
+    : new Set<string>();
+  const buzzAgentSelectable =
+    selectableRuntimes.some((runtime) => runtime.id === "buzz-agent") ||
+    (preserveCurrentRuntime && currentRuntimeId.trim() === "buzz-agent");
+  if (!buzzAgentSelectable) hidden.add("relay-mesh");
+  return hidden;
+}
+
 export const PERSONA_FIELD_SHELL_CLASS =
   "rounded-xl border border-input bg-muted/40 transition-colors duration-150 ease-out hover:border-muted-foreground/40 focus-within:border-muted-foreground/50";
 export const PERSONA_FIELD_CONTROL_CLASS =