diff --git a/desktop/src/features/agents/channelAgents.ts b/desktop/src/features/agents/channelAgents.ts
index 70a431a1e..ebb2f7a7e 100644
--- a/desktop/src/features/agents/channelAgents.ts
+++ b/desktop/src/features/agents/channelAgents.ts
@@ -61,10 +61,9 @@ export type CreateChannelManagedAgentInput = {
   /** Team this instance is deployed from; prevents cross-team reuse. */
   teamId?: string | null;
   /**
-   * True when `runtime` is a runtime the user deliberately picked to override
-   * the persona (a deploy-dialog runtime selector), as opposed to a
-   * missing-runtime fallback. Forwarded to the backend so a persona-backed
-   * create only pins the harness for a deliberate override.
+   * Pins `runtime` when the persona has no harness or the selection matches
+   * its harness. A fallback away from an unavailable configured harness stays
+   * unpinned so the persona remains authoritative.
    */
   harnessOverride?: boolean;
   /** Preferred model ID from the persona. Passed to createManagedAgent. */
diff --git a/desktop/src/features/channel-templates/useApplyTemplate.ts b/desktop/src/features/channel-templates/useApplyTemplate.ts
index 474767acf..dbb91ce67 100644
--- a/desktop/src/features/channel-templates/useApplyTemplate.ts
+++ b/desktop/src/features/channel-templates/useApplyTemplate.ts
@@ -9,6 +9,7 @@ import {
   usePersonasQuery,
   useTeamsQuery,
 } from "@/features/agents/hooks";
+import { shouldPinSelectedRuntimeForDefinition } from "@/features/agents/lib/instanceInputForDefinition";
 import { resolvePersonaRuntime } from "@/features/agents/lib/resolvePersonaRuntime";
 import { resolveTeamPersonas } from "@/features/agents/lib/teamPersonas";
 import { useLastRuntime } from "@/features/agents/lib/useLastRuntime";
@@ -86,8 +87,9 @@ export function useApplyTemplate() {
       if (!persona) continue;
       if (seenPersonaIds.has(persona.id)) continue;
       seenPersonaIds.add(persona.id);
+      const requestedRuntimeId = entry.runtime ?? persona.runtime;
       const resolved = resolvePersonaRuntime(
-        entry.runtime ?? persona.runtime,
+        requestedRuntimeId,
         runtimes,
         defaultProvider,
       );
@@ -96,6 +98,10 @@ export function useApplyTemplate() {
         runtime: resolved.runtime,
         name: persona.displayName,
         personaId: persona.id,
+        harnessOverride: shouldPinSelectedRuntimeForDefinition(
+          requestedRuntimeId,
+          resolved.runtime.id,
+        ),
         systemPrompt: persona.systemPrompt,
         avatarUrl: persona.avatarUrl ?? undefined,
         model: entry.model ?? persona.model ?? undefined,
@@ -112,8 +118,9 @@ export function useApplyTemplate() {
       for (const persona of resolvedPersonas) {
         if (seenPersonaIds.has(persona.id)) continue;
         seenPersonaIds.add(persona.id);
+        const requestedRuntimeId = teamEntry.runtime ?? persona.runtime;
         const resolved = resolvePersonaRuntime(
-          teamEntry.runtime ?? persona.runtime,
+          requestedRuntimeId,
           runtimes,
           defaultProvider,
         );
@@ -122,6 +129,10 @@ export function useApplyTemplate() {
           runtime: resolved.runtime,
           name: persona.displayName,
           personaId: persona.id,
+          harnessOverride: shouldPinSelectedRuntimeForDefinition(
+            requestedRuntimeId,
+            resolved.runtime.id,
+          ),
           systemPrompt: persona.systemPrompt,
           avatarUrl: persona.avatarUrl ?? undefined,
           model: teamEntry.model ?? persona.model ?? undefined,
diff --git a/desktop/src/features/channels/ui/AddChannelBotDialog.tsx b/desktop/src/features/channels/ui/AddChannelBotDialog.tsx
index 2c5a7515c..63bf6f438 100644
--- a/desktop/src/features/channels/ui/AddChannelBotDialog.tsx
+++ b/desktop/src/features/channels/ui/AddChannelBotDialog.tsx
@@ -12,6 +12,7 @@ import {
   canResolveAllPersonaRuntimes,
   resolvePersonaRuntime,
 } from "@/features/agents/lib/resolvePersonaRuntime";
+import { shouldPinSelectedRuntimeForDefinition } from "@/features/agents/lib/instanceInputForDefinition";
 import { getUsableTeams } from "@/features/agents/lib/teamPersonas";
 import { AddChannelBotPersonasSection } from "@/features/channels/ui/AddChannelBotPersonasSection";
 import { AddChannelBotTeamsSection } from "@/features/channels/ui/AddChannelBotTeamsSection";
@@ -159,7 +160,10 @@ export function AddChannelBotDialog({
           runtime: resolved.runtime,
           name: persona.displayName,
           personaId: persona.id,
-          harnessOverride: false,
+          harnessOverride: shouldPinSelectedRuntimeForDefinition(
+            persona.runtime,
+            resolved.runtime.id,
+          ),
           systemPrompt: persona.systemPrompt,
           avatarUrl: persona.avatarUrl ?? undefined,
           model: persona.model ?? undefined,