diff --git a/desktop/src-tauri/src/commands/agents.rs b/desktop/src-tauri/src/commands/agents.rs
index ef2654851d..fc31acb9f1 100644
--- a/desktop/src-tauri/src/commands/agents.rs
+++ b/desktop/src-tauri/src/commands/agents.rs
@@ -13,7 +13,7 @@ use crate::{
         DiscoverManagedAgentPrereqsRequest, ManagedAgentLogResponse, ManagedAgentPrereqsInfo,
         ManagedAgentSummary, MintManagedAgentTokenRequest, MintManagedAgentTokenResponse,
         RelayAgentInfo, DEFAULT_ACP_COMMAND, DEFAULT_AGENT_ARG, DEFAULT_AGENT_COMMAND,
-        DEFAULT_AGENT_TURN_TIMEOUT_SECONDS, DEFAULT_MCP_COMMAND,
+        DEFAULT_AGENT_PARALLELISM, DEFAULT_AGENT_TURN_TIMEOUT_SECONDS, DEFAULT_MCP_COMMAND,
     },
     relay::{
         build_authed_request, managed_agent_owner_pubkey, relay_ws_url, send_json_request,
@@ -94,6 +94,11 @@ pub async fn create_managed_agent(
     if name.is_empty() {
         return Err("agent name is required".to_string());
     }
+    if let Some(parallelism) = input.parallelism {
+        if !(1..=32).contains(&parallelism) {
+            return Err("parallelism must be between 1 and 32".to_string());
+        }
+    }
 
     let owner_pubkey = if input.mint_token {
         Some(managed_agent_owner_pubkey(&state).await?)
@@ -209,6 +214,16 @@ pub async fn create_managed_agent(
                     .turn_timeout_seconds
                     .filter(|seconds| *seconds > 0)
                     .unwrap_or(DEFAULT_AGENT_TURN_TIMEOUT_SECONDS),
+                parallelism: input
+                    .parallelism
+                    .filter(|count| (1..=32).contains(count))
+                    .unwrap_or(DEFAULT_AGENT_PARALLELISM),
+                system_prompt: input
+                    .system_prompt
+                    .as_deref()
+                    .map(str::trim)
+                    .filter(|value| !value.is_empty())
+                    .map(str::to_string),
                 created_at: now_iso(),
                 updated_at: now_iso(),
                 last_started_at: None,
diff --git a/desktop/src-tauri/src/managed_agents/runtime.rs b/desktop/src-tauri/src/managed_agents/runtime.rs
index b0e27381a5..66bef77bca 100644
--- a/desktop/src-tauri/src/managed_agents/runtime.rs
+++ b/desktop/src-tauri/src/managed_agents/runtime.rs
@@ -88,6 +88,8 @@ pub fn build_managed_agent_summary(
         agent_args: record.agent_args.clone(),
         mcp_command: record.mcp_command.clone(),
         turn_timeout_seconds: record.turn_timeout_seconds,
+        parallelism: record.parallelism,
+        system_prompt: record.system_prompt.clone(),
         has_api_token: record.api_token.is_some(),
         status,
         pid,
@@ -167,10 +169,16 @@ pub fn start_managed_agent_process(
         "SPROUT_ACP_TURN_TIMEOUT",
         record.turn_timeout_seconds.to_string(),
     );
+    command.env("SPROUT_ACP_AGENTS", record.parallelism.to_string());
     command.env(
         "GOOSE_MODE",
         std::env::var("GOOSE_MODE").unwrap_or_else(|_| "auto".to_string()),
     );
+    if let Some(system_prompt) = &record.system_prompt {
+        command.env("SPROUT_ACP_SYSTEM_PROMPT", system_prompt);
+    } else {
+        command.env_remove("SPROUT_ACP_SYSTEM_PROMPT");
+    }
     command.env_remove("SPROUT_ACP_PRIVATE_KEY");
     command.env_remove("SPROUT_ACP_API_TOKEN");
 
diff --git a/desktop/src-tauri/src/managed_agents/types.rs b/desktop/src-tauri/src/managed_agents/types.rs
index 374b60ae1d..d7dea01b19 100644
--- a/desktop/src-tauri/src/managed_agents/types.rs
+++ b/desktop/src-tauri/src/managed_agents/types.rs
@@ -24,6 +24,9 @@ pub struct ManagedAgentRecord {
     pub agent_args: Vec<String>,
     pub mcp_command: String,
     pub turn_timeout_seconds: u64,
+    #[serde(default = "default_agent_parallelism")]
+    pub parallelism: u32,
+    pub system_prompt: Option<String>,
     pub created_at: String,
     pub updated_at: String,
     pub last_started_at: Option<String>,
@@ -48,6 +51,8 @@ pub struct ManagedAgentSummary {
     pub agent_args: Vec<String>,
     pub mcp_command: String,
     pub turn_timeout_seconds: u64,
+    pub parallelism: u32,
+    pub system_prompt: Option<String>,
     pub has_api_token: bool,
     pub status: String,
     pub pid: Option<u32>,
@@ -71,6 +76,8 @@ pub struct CreateManagedAgentRequest {
     pub agent_args: Vec<String>,
     pub mcp_command: Option<String>,
     pub turn_timeout_seconds: Option<u64>,
+    pub parallelism: Option<u32>,
+    pub system_prompt: Option<String>,
     #[serde(default)]
     pub mint_token: bool,
     #[serde(default)]
@@ -155,3 +162,8 @@ pub const DEFAULT_AGENT_COMMAND: &str = "goose";
 pub const DEFAULT_MCP_COMMAND: &str = "sprout-mcp-server";
 pub const DEFAULT_AGENT_ARG: &str = "acp";
 pub const DEFAULT_AGENT_TURN_TIMEOUT_SECONDS: u64 = 300;
+pub const DEFAULT_AGENT_PARALLELISM: u32 = 1;
+
+fn default_agent_parallelism() -> u32 {
+    DEFAULT_AGENT_PARALLELISM
+}
diff --git a/desktop/src/features/agents/ui/CreateAgentDialog.tsx b/desktop/src/features/agents/ui/CreateAgentDialog.tsx
index 763c04fb8c..1f6bd00a5e 100644
--- a/desktop/src/features/agents/ui/CreateAgentDialog.tsx
+++ b/desktop/src/features/agents/ui/CreateAgentDialog.tsx
@@ -53,6 +53,8 @@ export function CreateAgentDialog({
     () => new Set<TokenScope>(DEFAULT_MANAGED_AGENT_SCOPES),
   );
   const [turnTimeoutSeconds, setTurnTimeoutSeconds] = React.useState("300");
+  const [parallelism, setParallelism] = React.useState("1");
+  const [systemPrompt, setSystemPrompt] = React.useState("");
   const [selectedProviderId, setSelectedProviderId] =
     React.useState<string>("custom");
   const [hasSyncedProviderSelection, setHasSyncedProviderSelection] =
@@ -133,6 +135,8 @@ export function CreateAgentDialog({
     setAgentArgs("acp");
     setMcpCommand("sprout-mcp-server");
     setTurnTimeoutSeconds("300");
+    setParallelism("1");
+    setSystemPrompt("");
     setSelectedProviderId("custom");
     setHasSyncedProviderSelection(false);
     setShowAdvanced(false);
@@ -202,6 +206,11 @@ export function CreateAgentDialog({
           Number.parseInt(turnTimeoutSeconds, 10) > 0
             ? Number.parseInt(turnTimeoutSeconds, 10)
             : undefined,
+        parallelism:
+          Number.parseInt(parallelism, 10) > 0
+            ? Number.parseInt(parallelism, 10)
+            : undefined,
+        systemPrompt: systemPrompt.trim() || undefined,
         mintToken,
         tokenName: tokenName.trim() || undefined,
         tokenScopes: [...selectedScopes],
@@ -280,7 +289,8 @@ export function CreateAgentDialog({
                     Advanced setup
                   </p>
                   <p className="text-sm text-muted-foreground">
-                    Relay overrides, raw commands, timeout, and doctor guidance.
+                    Relay overrides, raw commands, timeout, parallelism, prompt
+                    override, and doctor guidance.
                   </p>
                 </div>
                 <span className="shrink-0 self-center text-muted-foreground">
@@ -298,14 +308,18 @@ export function CreateAgentDialog({
                       agentArgs={agentArgs}
                       agentCommand={agentCommand}
                       mcpCommand={mcpCommand}
+                      onParallelismChange={setParallelism}
                       onAcpCommandChange={setAcpCommand}
                       onAgentArgsChange={setAgentArgs}
                       onAgentCommandChange={setAgentCommand}
                       onMcpCommandChange={setMcpCommand}
                       onRelayUrlChange={setRelayUrl}
+                      onSystemPromptChange={setSystemPrompt}
                       onTurnTimeoutChange={setTurnTimeoutSeconds}
+                      parallelism={parallelism}
                       relayUrl={relayUrl}
                       selectedProviderId={selectedProviderId}
+                      systemPrompt={systemPrompt}
                       turnTimeoutSeconds={turnTimeoutSeconds}
                     />
 
diff --git a/desktop/src/features/agents/ui/CreateAgentDialogSections.tsx b/desktop/src/features/agents/ui/CreateAgentDialogSections.tsx
index c787983877..3c17705695 100644
--- a/desktop/src/features/agents/ui/CreateAgentDialogSections.tsx
+++ b/desktop/src/features/agents/ui/CreateAgentDialogSections.tsx
@@ -6,6 +6,7 @@ import type {
 import { MANAGED_AGENT_SCOPE_OPTIONS } from "@/features/tokens/lib/scopeOptions";
 import { cn } from "@/shared/lib/cn";
 import { Input } from "@/shared/ui/input";
+import { Textarea } from "@/shared/ui/textarea";
 import { describeResolvedCommand } from "./agentUi";
 
 export function CreateAgentBasicsFields({
@@ -98,28 +99,36 @@ export function CreateAgentRuntimeFields({
   agentArgs,
   agentCommand,
   mcpCommand,
+  parallelism,
   relayUrl,
   selectedProviderId,
+  systemPrompt,
   turnTimeoutSeconds,
   onAcpCommandChange,
   onAgentArgsChange,
   onAgentCommandChange,
   onMcpCommandChange,
+  onParallelismChange,
   onRelayUrlChange,
+  onSystemPromptChange,
   onTurnTimeoutChange,
 }: {
   acpCommand: string;
   agentArgs: string;
   agentCommand: string;
   mcpCommand: string;
+  parallelism: string;
   relayUrl: string;
   selectedProviderId: string;
+  systemPrompt: string;
   turnTimeoutSeconds: string;
   onAcpCommandChange: (value: string) => void;
   onAgentArgsChange: (value: string) => void;
   onAgentCommandChange: (value: string) => void;
   onMcpCommandChange: (value: string) => void;
+  onParallelismChange: (value: string) => void;
   onRelayUrlChange: (value: string) => void;
+  onSystemPromptChange: (value: string) => void;
   onTurnTimeoutChange: (value: string) => void;
 }) {
   return (
@@ -165,7 +174,7 @@ export function CreateAgentRuntimeFields({
         </div>
       ) : null}
 
-      <div className="grid gap-4 md:grid-cols-[1.5fr,1.2fr,0.8fr]">
+      <div className="grid gap-4 md:grid-cols-[1.5fr,1.2fr,0.8fr,0.8fr]">
         <div className="space-y-1.5">
           <label className="text-sm font-medium" htmlFor="agent-runtime-args">
             Agent runtime args
@@ -199,9 +208,48 @@ export function CreateAgentRuntimeFields({
           <Input
             id="agent-timeout"
             onChange={(event) => onTurnTimeoutChange(event.target.value)}
+            placeholder="300"
             value={turnTimeoutSeconds}
           />
         </div>
+
+        <div className="space-y-1.5">
+          <label className="text-sm font-medium" htmlFor="agent-parallelism">
+            Parallelism
+          </label>
+          <Input
+            data-testid="agent-parallelism-input"
+            id="agent-parallelism"
+            inputMode="numeric"
+            max="32"
+            min="1"
+            onChange={(event) => onParallelismChange(event.target.value)}
+            placeholder="1"
+            step="1"
+            type="number"
+            value={parallelism}
+          />
+          <p className="text-xs text-muted-foreground">
+            Number of ACP worker subprocesses. `sprout-acp` allows 1-32.
+          </p>
+        </div>
+      </div>
+
+      <div className="space-y-1.5">
+        <label className="text-sm font-medium" htmlFor="agent-system-prompt">
+          System prompt override
+        </label>
+        <Textarea
+          data-testid="agent-system-prompt-input"
+          id="agent-system-prompt"
+          onChange={(event) => onSystemPromptChange(event.target.value)}
+          placeholder="Leave blank to send no ACP system prompt"
+          value={systemPrompt}
+        />
+        <p className="text-xs text-muted-foreground">
+          Blank means no override. `sprout-acp` will not add a `[System]`
+          prompt.
+        </p>
       </div>
     </>
   );
diff --git a/desktop/src/features/agents/ui/ManagedAgentLogPanel.tsx b/desktop/src/features/agents/ui/ManagedAgentLogPanel.tsx
index fcccb5cf22..605ac88351 100644
--- a/desktop/src/features/agents/ui/ManagedAgentLogPanel.tsx
+++ b/desktop/src/features/agents/ui/ManagedAgentLogPanel.tsx
@@ -54,7 +54,10 @@ export function ManagedAgentLogPanel({
             <span>{selectedAgent.name}</span>
             <span>{selectedAgent.status}</span>
           </div>
-          <pre className="max-h-[22rem] overflow-auto whitespace-pre-wrap px-4 py-4">
+          <pre
+            className="max-h-[22rem] overflow-auto whitespace-pre-wrap px-4 py-4"
+            data-testid="managed-agent-log-content"
+          >
             {logContent?.trim() ? logContent : "No log output yet."}
           </pre>
         </div>
diff --git a/desktop/src/features/messages/lib/formatTimelineMessages.ts b/desktop/src/features/messages/lib/formatTimelineMessages.ts
index 96b5d7781a..f641cb843e 100644
--- a/desktop/src/features/messages/lib/formatTimelineMessages.ts
+++ b/desktop/src/features/messages/lib/formatTimelineMessages.ts
@@ -239,10 +239,6 @@ export function formatTimelineMessages(
     const authorPubkey =
       authorPubkeyByEventId.get(event.id) ?? getEffectiveAuthorPubkey(event);
     const thread = getThreadReference(event.tags);
-    const parentEvent = thread.parentId
-      ? eventsById.get(thread.parentId)
-      : undefined;
-
     return {
       id: event.id,
       createdAt: event.created_at,
@@ -262,8 +258,6 @@ export function formatTimelineMessages(
       parentId: thread.parentId,
       rootId: thread.rootId,
       depth: getDepth(event),
-      replyToAuthor: parentEvent ? getAuthorLabel(parentEvent) : null,
-      replyToSnippet: parentEvent?.content ?? null,
       accent: currentPubkey === authorPubkey,
       pending: event.pending,
       kind: event.kind,
diff --git a/desktop/src/features/messages/types.ts b/desktop/src/features/messages/types.ts
index 7bfad3f995..db962d6379 100644
--- a/desktop/src/features/messages/types.ts
+++ b/desktop/src/features/messages/types.ts
@@ -16,8 +16,6 @@ export type TimelineMessage = {
   parentId?: string | null;
   rootId?: string | null;
   depth: number;
-  replyToAuthor?: string | null;
-  replyToSnippet?: string | null;
   accent?: boolean;
   pending?: boolean;
   highlighted?: boolean;
diff --git a/desktop/src/features/messages/ui/MessageRow.tsx b/desktop/src/features/messages/ui/MessageRow.tsx
index 3c2b3edb90..ecfc135a8e 100644
--- a/desktop/src/features/messages/ui/MessageRow.tsx
+++ b/desktop/src/features/messages/ui/MessageRow.tsx
@@ -37,7 +37,6 @@ export function MessageRow({
   >(null);
   const [reactionPending, setReactionPending] = React.useState(false);
   const visibleDepth = Math.min(message.depth, 6);
-  const compressedDepth = Math.max(message.depth - visibleDepth, 0);
   const indentPx = visibleDepth * 28;
   const initials = message.author
     .split(" ")
@@ -190,25 +189,6 @@ export function MessageRow({
         )}
 
         <div className="min-w-0 flex-1 space-y-0">
-          {message.parentId ? (
-            <div className="mb-1 flex min-w-0 flex-wrap items-center gap-2 text-[11px] font-medium uppercase tracking-[0.16em] text-muted-foreground">
-              <span className="rounded-full bg-muted px-2 py-0.5 text-[10px]">
-                Reply
-              </span>
-              <span className="truncate normal-case tracking-normal">
-                {message.replyToAuthor
-                  ? `to ${message.replyToAuthor}`
-                  : "to an earlier message"}
-              </span>
-              {compressedDepth > 0 ? (
-                <span className="rounded-full bg-muted px-2 py-0.5 text-[10px]">
-                  +{compressedDepth} more level
-                  {compressedDepth === 1 ? "" : "s"}
-                </span>
-              ) : null}
-            </div>
-          ) : null}
-
           <div className="flex min-w-0 flex-wrap items-center gap-2">
             {message.pubkey ? (
               <UserProfilePopover pubkey={message.pubkey}>
@@ -291,13 +271,6 @@ export function MessageRow({
               {reactionErrorMessage}
             </p>
           ) : null}
-          <div className="mt-2 flex items-center gap-2">
-            {message.replyToSnippet ? (
-              <p className="truncate text-xs text-muted-foreground">
-                {message.replyToSnippet}
-              </p>
-            ) : null}
-          </div>
           {expandedDiffId === message.id ? (
             <React.Suspense
               fallback={
diff --git a/desktop/src/features/sidebar/ui/AppSidebar.tsx b/desktop/src/features/sidebar/ui/AppSidebar.tsx
index 78af23595d..4a4b036058 100644
--- a/desktop/src/features/sidebar/ui/AppSidebar.tsx
+++ b/desktop/src/features/sidebar/ui/AppSidebar.tsx
@@ -443,6 +443,7 @@ export function AppSidebar({
           </SidebarMenuItem>
           <SidebarMenuItem>
             <SidebarMenuButton
+              data-testid="open-agents-view"
               isActive={selectedView === "agents"}
               onClick={onSelectAgents}
               tooltip="Agents"
diff --git a/desktop/src/shared/api/tauri.ts b/desktop/src/shared/api/tauri.ts
index 9a047865cf..928259324e 100644
--- a/desktop/src/shared/api/tauri.ts
+++ b/desktop/src/shared/api/tauri.ts
@@ -214,6 +214,8 @@ type RawManagedAgent = {
   agent_args: string[];
   mcp_command: string;
   turn_timeout_seconds: number;
+  parallelism: number;
+  system_prompt: string | null;
   has_api_token: boolean;
   status: ManagedAgent["status"];
   pid: number | null;
@@ -711,6 +713,8 @@ function fromRawManagedAgent(agent: RawManagedAgent): ManagedAgent {
     agentArgs: agent.agent_args,
     mcpCommand: agent.mcp_command,
     turnTimeoutSeconds: agent.turn_timeout_seconds,
+    parallelism: agent.parallelism,
+    systemPrompt: agent.system_prompt,
     hasApiToken: agent.has_api_token,
     status: agent.status,
     pid: agent.pid,
@@ -804,6 +808,8 @@ export async function createManagedAgent(
         agentArgs: input.agentArgs,
         mcpCommand: input.mcpCommand,
         turnTimeoutSeconds: input.turnTimeoutSeconds,
+        parallelism: input.parallelism,
+        systemPrompt: input.systemPrompt,
         mintToken: input.mintToken,
         tokenScopes: input.tokenScopes,
         tokenName: input.tokenName,
diff --git a/desktop/src/shared/api/types.ts b/desktop/src/shared/api/types.ts
index 0d285524b4..e4b0987152 100644
--- a/desktop/src/shared/api/types.ts
+++ b/desktop/src/shared/api/types.ts
@@ -253,6 +253,8 @@ export type ManagedAgent = {
   agentArgs: string[];
   mcpCommand: string;
   turnTimeoutSeconds: number;
+  parallelism: number;
+  systemPrompt: string | null;
   hasApiToken: boolean;
   status: "running" | "stopped";
   pid: number | null;
@@ -273,6 +275,8 @@ export type CreateManagedAgentInput = {
   agentArgs?: string[];
   mcpCommand?: string;
   turnTimeoutSeconds?: number;
+  parallelism?: number;
+  systemPrompt?: string;
   mintToken?: boolean;
   tokenScopes?: TokenScope[];
   tokenName?: string;
diff --git a/desktop/src/testing/e2eBridge.ts b/desktop/src/testing/e2eBridge.ts
index 299eef0e09..53aa1c44e5 100644
--- a/desktop/src/testing/e2eBridge.ts
+++ b/desktop/src/testing/e2eBridge.ts
@@ -208,6 +208,8 @@ type RawManagedAgent = {
   agent_args: string[];
   mcp_command: string;
   turn_timeout_seconds: number;
+  parallelism: number;
+  system_prompt: string | null;
   has_api_token: boolean;
   status: "running" | "stopped";
   pid: number | null;
@@ -224,6 +226,7 @@ type RawCreateManagedAgentResponse = {
   agent: RawManagedAgent;
   private_key_nsec: string;
   api_token: string | null;
+  profile_sync_error: string | null;
   spawn_error: string | null;
 };
 
@@ -469,6 +472,8 @@ function cloneManagedAgent(agent: MockManagedAgent): RawManagedAgent {
     agent_args: [...agent.agent_args],
     mcp_command: agent.mcp_command,
     turn_timeout_seconds: agent.turn_timeout_seconds,
+    parallelism: agent.parallelism,
+    system_prompt: agent.system_prompt,
     has_api_token: agent.has_api_token,
     status: agent.status,
     pid: agent.pid,
@@ -2030,6 +2035,8 @@ async function handleCreateManagedAgent(args: {
     agentArgs?: string[];
     mcpCommand?: string;
     turnTimeoutSeconds?: number;
+    parallelism?: number;
+    systemPrompt?: string;
     mintToken?: boolean;
     tokenScopes?: string[];
     tokenName?: string;
@@ -2059,6 +2066,8 @@ async function handleCreateManagedAgent(args: {
         : ["acp"],
     mcp_command: args.input.mcpCommand ?? "sprout-mcp-server",
     turn_timeout_seconds: args.input.turnTimeoutSeconds ?? 300,
+    parallelism: args.input.parallelism ?? 1,
+    system_prompt: args.input.systemPrompt?.trim() || null,
     has_api_token: token !== null,
     status: args.input.spawnAfterCreate ? "running" : "stopped",
     pid: args.input.spawnAfterCreate ? 42000 + mockManagedAgents.length : null,
@@ -2072,7 +2081,10 @@ async function handleCreateManagedAgent(args: {
     private_key_nsec: `nsec1mock${pubkey.slice(0, 20)}`,
     api_token: token,
     log_lines: [
-      `sprout-acp starting: relay=${args.input.relayUrl ?? DEFAULT_RELAY_WS_URL} agent_pubkey=${pubkey}`,
+      `sprout-acp starting: relay=${args.input.relayUrl ?? DEFAULT_RELAY_WS_URL} agent_pubkey=${pubkey} parallelism=${args.input.parallelism ?? 1}`,
+      args.input.systemPrompt?.trim()
+        ? `system prompt override configured (${args.input.systemPrompt.trim().length} chars)`
+        : "system prompt override not set",
       args.input.spawnAfterCreate
         ? "connected to relay at ws://localhost:3000"
         : "profile created; harness not started",
@@ -2086,6 +2098,7 @@ async function handleCreateManagedAgent(args: {
     agent: cloneManagedAgent(managedAgent),
     private_key_nsec: managedAgent.private_key_nsec,
     api_token: managedAgent.api_token,
+    profile_sync_error: null,
     spawn_error: null,
   };
 }
diff --git a/desktop/tests/e2e/messaging.spec.ts b/desktop/tests/e2e/messaging.spec.ts
index 4ae57c19ea..fe9cc59330 100644
--- a/desktop/tests/e2e/messaging.spec.ts
+++ b/desktop/tests/e2e/messaging.spec.ts
@@ -214,6 +214,7 @@ test("supports nested replies with visible indentation", async ({ page }) => {
   await page.getByTestId("message-input").fill(firstReply);
   await page.getByTestId("send-message").click();
   await expect(rows.last()).toContainText(firstReply);
+  await expect(rows.last()).not.toContainText("Welcome to #general");
 
   await rows.last().hover();
   await replyButtons.last().click();
@@ -221,6 +222,7 @@ test("supports nested replies with visible indentation", async ({ page }) => {
   await page.getByTestId("message-input").fill(nestedReply);
   await page.getByTestId("send-message").click();
   await expect(rows.last()).toContainText(nestedReply);
+  await expect(rows.last()).not.toContainText(firstReply);
 
   const rootBox = await rows.nth(0).boundingBox();
   const firstReplyBox = await rows.nth(1).boundingBox();
diff --git a/desktop/tests/e2e/smoke.spec.ts b/desktop/tests/e2e/smoke.spec.ts
index d2ff850f9d..e25d9b96b1 100644
--- a/desktop/tests/e2e/smoke.spec.ts
+++ b/desktop/tests/e2e/smoke.spec.ts
@@ -68,6 +68,36 @@ test("creates a new mocked stream", async ({ page }) => {
   await expect(page.getByTestId("chat-title")).toHaveText(channelName);
 });
 
+test("create agent supports parallelism and system prompt overrides", async ({
+  page,
+}) => {
+  const agentName = `Parallel agent ${Date.now()}`;
+
+  await page.goto("/");
+  await page.getByTestId("open-agents-view").click();
+  await page.getByRole("button", { name: "Create agent" }).click();
+
+  await page.getByTestId("agent-name-input").fill(agentName);
+  await page.getByRole("button", { name: "Advanced setup" }).click();
+  await page.getByTestId("agent-parallelism-input").fill("3");
+  await page
+    .getByTestId("agent-system-prompt-input")
+    .fill("You are concise and parallelize independent work.");
+  await page.getByTestId("create-agent-submit").click();
+
+  await expect(
+    page.getByRole("heading", { name: "Agent created" }),
+  ).toBeVisible();
+  await page.getByRole("button", { name: "Done" }).click();
+
+  await expect(page.getByTestId("managed-agent-log-content")).toContainText(
+    "parallelism=3",
+  );
+  await expect(page.getByTestId("managed-agent-log-content")).toContainText(
+    "system prompt override configured",
+  );
+});
+
 test("opens a mocked channel from the home feed", async ({ page }) => {
   const mentionsSection = page.locator("section").filter({
     has: page.getByRole("heading", { name: "@Mentions" }),