fix(desktop): correct provider and model handling in agent config dialogs

desktop/playwright.config.ts

@@ -93,6 +93,7 @@ export default defineConfig({
         "**/global-agent-config-screenshots.spec.ts",
         "**/doctor-states.spec.ts",
         "**/agent-lifecycle-feedback.spec.ts",
+        "**/agent-provider-dropdowns.spec.ts",
       ],
       use: {
         ...devices["Desktop Chrome"],

desktop/scripts/check-file-sizes.mjs

@@ -403,7 +403,14 @@ const overrides = new Map([
   // +23 rebase onto #1667: behavioral quad fields (respond_to/parallelism/toolsets)
   // plumbed through AgentInstanceEditDialog from PersonaAdvancedFields.
   // +2 provider-aware effort: model/provider props threaded to BuzzAgentModelTuningFields.
-  ["src/features/agents/ui/AgentInstanceEditDialog.tsx", 1165],
+  // +15 provider/model dropdown fixes: useBakedBuildEnvKeysQuery + hideProviderIds
+  // for Databricks v1 gate; prospectiveRuntimeId default fallback for builtins.
+  ["src/features/agents/ui/AgentInstanceEditDialog.tsx", 1180],
+  // AgentDefinitionDialog grew past 1000 with the following load-bearing fixes:
+  // isRuntimeAutoSeededRef tracking for edit-mode seeding (Fizz shows models);
+  // runtimeSupportsLlmProviderSelection guard on discovery provider (codex fix);
+  // hideProviderIds computation for Databricks v1 gate. Queued to split.
+  ["src/features/agents/ui/AgentDefinitionDialog.tsx", 1035],
 ]);
 
 await runFileSizeCheck({

desktop/src/features/agents/hooks.ts

@@ -57,7 +57,6 @@ import type {
 } from "@/shared/api/types";
 import type {
   AttachManagedAgentToChannelInput,
-  AttachManagedAgentToChannelResult,
   CreateChannelManagedAgentInput,
   CreateChannelManagedAgentsResult,
   CreateChannelManagedAgentResult,
@@ -84,10 +83,6 @@ export const acpRuntimesQueryKey = ["acp-runtimes"] as const;
 export const managedAgentPrereqsQueryKey = ["managed-agent-prereqs"] as const;
 export const backendProvidersQueryKey = ["backend-providers"] as const;
 
-export type EnsureGooseInChannelResult = AttachManagedAgentToChannelResult & {
-  created: boolean;
-};
-
 async function invalidateAgentQueries(
   queryClient: ReturnType<typeof useQueryClient>,
   channelId: string | null,
@@ -590,39 +585,6 @@ export function useCreateChannelManagedAgentsMutation(
   });
 }
 
-export function useEnsureGooseInChannelMutation(channelId: string | null) {
-  const queryClient = useQueryClient();
-
-  return useMutation({
-    mutationFn: async (): Promise<EnsureGooseInChannelResult> => {
-      if (!channelId) {
-        throw new Error("No channel selected.");
-      }
-
-      const attached = await ensureChannelAgentPresetInChannel(channelId, {
-        runtime: {
-          id: "goose",
-          label: "Goose",
-          command: "goose",
-          defaultArgs: ["acp"],
-          mcpCommand: null,
-        },
-        role: "bot",
-      });
-
-      return {
-        agent: attached.agent,
-        membershipAdded: attached.membershipAdded,
-        started: attached.started,
-        created: attached.created,
-      };
-    },
-    onSettled: () => {
-      invalidateAgentQueriesInBackground(queryClient, channelId);
-    },
-  });
-}
-
 export function useExportPersonaJsonMutation() {
   return useMutation({
     mutationFn: (id: string) => exportPersonaToJson(id),

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

@@ -42,6 +42,14 @@ const claudeRuntime = {
   mcpCommand: null,
 };
 
+const buzzAgentRuntime = {
+  ...gooseRuntime,
+  id: "buzz-agent",
+  label: "Buzz Agent",
+  command: "buzz-agent-cmd",
+  mcpCommand: null,
+};
+
 function persona(overrides = {}) {
   return {
     id: "p-1",
@@ -346,3 +354,40 @@ test("row 6: unfetched query refetches instead of resolving empty", async () =>
     "an unfetched query must fetch, not spuriously report no runtimes",
   );
 });
+
+// ── item-13 regression: buzz-agent-first default runtime ─────────────────────
+//
+// Before this fix, resolveStartRuntimeForDefinition used runtimes[0] (catalog
+// order: goose, claude, codex, buzz-agent), so an installed goose would beat
+// the bundled buzz-agent sidecar as the default for runtime-less personas.
+// The fix applies the preference order: buzz-agent → goose → first available.
+
+test("item-13: goose+buzz-agent both available — persona with no runtime resolves buzz-agent", () => {
+  const { runtime, warnings } = resolveStartRuntimeForDefinition(
+    persona({ runtime: undefined }),
+    [gooseRuntime, claudeRuntime, buzzAgentRuntime],
+  );
+  assert.equal(
+    runtime.id,
+    "buzz-agent",
+    "buzz-agent must win over catalog-first goose for runtime-less personas",
+  );
+  assert.deepEqual(warnings, []);
+});
+
+test("item-13: goose-only available — persona with no runtime resolves goose", () => {
+  const { runtime, warnings } = resolveStartRuntimeForDefinition(
+    persona({ runtime: undefined }),
+    [gooseRuntime, claudeRuntime],
+  );
+  assert.equal(runtime.id, "goose");
+  assert.deepEqual(warnings, []);
+});
+
+test("item-13: no runtimes available — refuses with actionable error", () => {
+  assert.throws(
+    () => resolveStartRuntimeForDefinition(persona({ runtime: undefined }), []),
+    /No available runtime/,
+    "empty runtime list must throw, not silently return null",
+  );
+});

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

@@ -7,6 +7,7 @@ import type {
 import type { MeshAgentPresetPatch } from "@/features/mesh-compute/applyMeshAgentPreset";
 import type { MeshServeTarget } from "@/shared/api/tauriMesh";
 import {
+  getDefaultPersonaRuntime,
   resolvePersonaRuntime,
   type ResolvePersonaRuntimeResult,
 } from "./resolvePersonaRuntime";
@@ -47,7 +48,10 @@ export function resolveStartRuntimeForDefinition(
   persona: AgentPersona,
   runtimes: readonly AcpRuntime[],
 ): { runtime: AcpRuntime; warnings: string[] } {
-  const defaultRuntime = runtimes[0] ?? null;
+  // Use the buzz-agent-first preference (buzz-agent → goose → first available)
+  // so a freshly installed goose never beats the bundled buzz-agent sidecar
+  // for runtime-less personas (item 13 regression guard).
+  const defaultRuntime = getDefaultPersonaRuntime(runtimes);
   const { runtime, warnings, isOverridden }: ResolvePersonaRuntimeResult =
     resolvePersonaRuntime(persona.runtime, runtimes, defaultRuntime);
 

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

@@ -1,4 +1,28 @@
-import type { AcpRuntime } from "@/shared/api/types";
+import type { AcpRuntime, AcpRuntimeCatalogEntry } from "@/shared/api/types";
+
+/**
+ * Select the best default runtime from a catalog, using the same preference
+ * order as the UI picker: buzz-agent first (bundled sidecar), then goose,
+ * then the first available entry, then null when nothing is available.
+ *
+ * Generic so that passing AcpRuntime[] (the already-filtered start-path
+ * list) returns AcpRuntime | null while passing AcpRuntimeCatalogEntry[]
+ * (the full catalog) returns AcpRuntimeCatalogEntry | null.  Both call sites
+ * share one preference-order implementation.
+ */
+export function getDefaultPersonaRuntime<T extends AcpRuntimeCatalogEntry>(
+  runtimes: readonly T[],
+): T | null {
+  const available = runtimes.filter(
+    (runtime) => runtime.availability === "available",
+  );
+  return (
+    available.find((runtime) => runtime.id === "buzz-agent") ??
+    available.find((runtime) => runtime.id === "goose") ??
+    available[0] ??
+    null
+  );
+}
 
 /**
  * Result of resolving a persona's preferred runtime against the set of

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

@@ -12,6 +12,7 @@ import {
 } from "@/features/agents/lib/teamPersonas";
 import {
   collectRuntimeWarnings,
+  getDefaultPersonaRuntime,
   resolvePersonaRuntime,
 } from "@/features/agents/lib/resolvePersonaRuntime";
 import { useChannelsQuery } from "@/features/channels/hooks";
@@ -65,8 +66,10 @@ export function AddTeamToChannelDialog({
     [channelsQuery.data],
   );
 
-  const providers = providersQuery.data ?? [];
-  const defaultProvider = providers[0] ?? null;
+  const runtimes = providersQuery.data ?? [];
+  // Use the buzz-agent-first preference so the team-deploy fallback mirrors the
+  // single-agent start path (buzz-agent → goose → first available).
+  const defaultProvider = getDefaultPersonaRuntime(runtimes);
 
   const teamPersonaResolution = React.useMemo(
     () =>
@@ -80,8 +83,8 @@ export function AddTeamToChannelDialog({
   // This dialog has no runtime selector, so the fallback is always
   // `defaultProvider` (the first available runtime).
   const runtimeWarnings = React.useMemo(
-    () => collectRuntimeWarnings(resolved, providers, defaultProvider),
-    [resolved, providers, defaultProvider],
+    () => collectRuntimeWarnings(resolved, runtimes, defaultProvider),
+    [resolved, runtimes, defaultProvider],
   );
 
   function reset() {
@@ -122,7 +125,7 @@ export function AddTeamToChannelDialog({
       const inputs = resolved.map((persona) => {
         const { runtime: personaRuntime } = resolvePersonaRuntime(
           persona.runtime,
-          providers,
+          runtimes,
           defaultProvider,
         );
         const runtimeToUse = personaRuntime ?? defaultProvider;