feat(web): MS23-P2-008 panel grid responsive layout

apps/web/src/components/mission-control/BargeInInput.tsx

@@ -0,0 +1,147 @@
+"use client";
+
+import { useCallback, useState, type KeyboardEvent } from "react";
+import { Loader2 } from "lucide-react";
+import { useToast } from "@mosaic/ui";
+import { Button } from "@/components/ui/button";
+import { apiPost } from "@/lib/api/client";
+
+const MAX_ROWS = 4;
+const TEXTAREA_MAX_HEIGHT_REM = 6.5;
+
+interface BargeInMutationResponse {
+  message?: string;
+}
+
+export interface BargeInInputProps {
+  sessionId: string;
+  onSent?: () => void;
+}
+
+function getErrorMessage(error: unknown): string {
+  if (error instanceof Error && error.message.trim().length > 0) {
+    return error.message;
+  }
+  return "Failed to send message to the session.";
+}
+
+export function BargeInInput({ sessionId, onSent }: BargeInInputProps): React.JSX.Element {
+  const { showToast } = useToast();
+  const [content, setContent] = useState("");
+  const [pauseBeforeSend, setPauseBeforeSend] = useState(false);
+  const [isSending, setIsSending] = useState(false);
+  const [errorMessage, setErrorMessage] = useState<string | null>(null);
+
+  const handleSend = useCallback(async (): Promise<void> => {
+    const trimmedContent = content.trim();
+    if (!trimmedContent || isSending) {
+      return;
+    }
+
+    const encodedSessionId = encodeURIComponent(sessionId);
+    const baseEndpoint = `/api/mission-control/sessions/${encodedSessionId}`;
+    let didPause = false;
+    let didInject = false;
+
+    setIsSending(true);
+    setErrorMessage(null);
+
+    try {
+      if (pauseBeforeSend) {
+        await apiPost<BargeInMutationResponse>(`${baseEndpoint}/pause`);
+        didPause = true;
+      }
+
+      await apiPost<BargeInMutationResponse>(`${baseEndpoint}/inject`, { content: trimmedContent });
+      didInject = true;
+      setContent("");
+      onSent?.();
+    } catch (error) {
+      const message = getErrorMessage(error);
+      setErrorMessage(message);
+      showToast(message, "error");
+    } finally {
+      if (didPause) {
+        try {
+          await apiPost<BargeInMutationResponse>(`${baseEndpoint}/resume`);
+        } catch (resumeError) {
+          const resumeMessage = getErrorMessage(resumeError);
+          const message = didInject
+            ? `Message sent, but failed to resume session: ${resumeMessage}`
+            : `Failed to resume session: ${resumeMessage}`;
+          setErrorMessage(message);
+          showToast(message, "error");
+        }
+      }
+
+      setIsSending(false);
+    }
+  }, [content, isSending, onSent, pauseBeforeSend, sessionId, showToast]);
+
+  const handleKeyDown = useCallback(
+    (event: KeyboardEvent<HTMLTextAreaElement>): void => {
+      if (event.key === "Enter" && !event.shiftKey) {
+        event.preventDefault();
+        void handleSend();
+      }
+    },
+    [handleSend]
+  );
+
+  const isSendDisabled = isSending || content.trim().length === 0;
+
+  return (
+    <div className="space-y-2">
+      <textarea
+        value={content}
+        onChange={(event) => {
+          setContent(event.target.value);
+        }}
+        onKeyDown={handleKeyDown}
+        disabled={isSending}
+        rows={MAX_ROWS}
+        placeholder="Inject a message into this session..."
+        className="block w-full resize-y rounded-md border border-border bg-background px-3 py-2 text-sm leading-5 text-foreground outline-none placeholder:text-muted-foreground disabled:cursor-not-allowed disabled:opacity-60"
+        style={{ maxHeight: `${String(TEXTAREA_MAX_HEIGHT_REM)}rem` }}
+        aria-label="Inject message"
+      />
+      <div className="flex items-center justify-between gap-3">
+        <label className="flex items-center gap-2 text-sm text-muted-foreground">
+          <input
+            type="checkbox"
+            checked={pauseBeforeSend}
+            onChange={(event) => {
+              setPauseBeforeSend(event.target.checked);
+            }}
+            disabled={isSending}
+            className="h-4 w-4 rounded border-border"
+          />
+          <span>Pause before send</span>
+        </label>
+        <Button
+          type="button"
+          variant="primary"
+          size="sm"
+          disabled={isSendDisabled}
+          onClick={() => {
+            void handleSend();
+          }}
+        >
+          {isSending ? (
+            <span className="flex items-center gap-2">
+              <Loader2 className="h-4 w-4 animate-spin" aria-hidden="true" />
+              Sending...
+            </span>
+          ) : (
+            "Send"
+          )}
+        </Button>
+      </div>
+      {errorMessage ? (
+        <p role="alert" className="text-sm text-red-500">
+          {errorMessage}
+        </p>
+      ) : null}
+    </div>
+  );
+}

apps/web/src/components/mission-control/GlobalAgentRoster.tsx

@@ -4,6 +4,7 @@ import { useMemo, useState } from "react";
 import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
 import type { AgentSession } from "@mosaic/shared";
 import { ChevronRight, Loader2, X } from "lucide-react";
+import { KillAllDialog } from "@/components/mission-control/KillAllDialog";
 import { Badge } from "@/components/ui/badge";
 import type { BadgeVariant } from "@/components/ui/badge";
 import { Button } from "@/components/ui/button";
@@ -36,7 +37,7 @@ interface ProviderSessionGroup {
 
 export interface GlobalAgentRosterProps {
   onSelectSession?: (sessionId: string) => void;
-  selectedSessionId?: string;
+  selectedSessionId?: string | undefined;
 }
 
 function getStatusVariant(status: MissionControlSessionStatus): BadgeVariant {
@@ -87,6 +88,21 @@ async function fetchSessions(): Promise<MissionControlSession[]> {
   return Array.isArray(payload) ? payload : payload.sessions;
 }
 
+function toKillAllSessions(sessions: MissionControlSession[]): AgentSession[] {
+  return sessions
+    .filter(
+      (session): session is MissionControlSession & { status: AgentSession["status"] } =>
+        session.status !== "killed"
+    )
+    .map((session) => ({
+      ...session,
+      createdAt:
+        session.createdAt instanceof Date ? session.createdAt : new Date(session.createdAt),
+      updatedAt:
+        session.updatedAt instanceof Date ? session.updatedAt : new Date(session.updatedAt),
+    }));
+}
+
 export function GlobalAgentRoster({
   onSelectSession,
   selectedSessionId,
@@ -117,6 +133,13 @@ export function GlobalAgentRoster({
     [sessionsQuery.data]
   );
 
+  const killAllSessions = useMemo(
+    () => toKillAllSessions(sessionsQuery.data ?? []),
+    [sessionsQuery.data]
+  );
+
+  const totalSessionCount = sessionsQuery.data?.length ?? 0;
+
   const pendingKillSessionId = killMutation.isPending ? killMutation.variables : undefined;
 
   const toggleProvider = (providerId: string): void => {
@@ -128,14 +151,23 @@ export function GlobalAgentRoster({
 
   const isProviderOpen = (providerId: string): boolean => openProviders[providerId] ?? true;
 
+  const handleKillAllComplete = (): void => {
+    void queryClient.invalidateQueries({ queryKey: SESSIONS_QUERY_KEY });
+  };
+
   return (
     <Card className="flex h-full min-h-0 flex-col">
       <CardHeader className="pb-2">
-        <CardTitle className="flex items-center justify-between text-base">
+        <CardTitle className="flex items-center justify-between gap-2 text-base">
           <span>Agent Roster</span>
-          {sessionsQuery.isFetching && !sessionsQuery.isLoading ? (
+          <div className="flex items-center gap-2">
-            <Loader2 className="h-4 w-4 animate-spin text-muted-foreground" aria-hidden="true" />
+            {totalSessionCount > 0 ? (
-          ) : null}
+              <KillAllDialog sessions={killAllSessions} onComplete={handleKillAllComplete} />
+            ) : null}
+            {sessionsQuery.isFetching && !sessionsQuery.isLoading ? (
+              <Loader2 className="h-4 w-4 animate-spin text-muted-foreground" aria-hidden="true" />
+            ) : null}
+          </div>
         </CardTitle>
       </CardHeader>
       <CardContent className="min-h-0 flex-1 px-3 pb-3">

apps/web/src/components/mission-control/KillAllDialog.tsx

@@ -0,0 +1,224 @@
+"use client";
+
+import { useEffect, useMemo, useRef, useState } from "react";
+import type { AgentSession } from "@mosaic/shared";
+import { Loader2 } from "lucide-react";
+import { Button } from "@/components/ui/button";
+import {
+  Dialog,
+  DialogContent,
+  DialogDescription,
+  DialogFooter,
+  DialogHeader,
+  DialogTitle,
+  DialogTrigger,
+} from "@/components/ui/dialog";
+import { Input } from "@/components/ui/input";
+import { Label } from "@/components/ui/label";
+import { apiPost } from "@/lib/api/client";
+
+const CONFIRM_TEXT = "KILL ALL";
+const AUTO_CLOSE_DELAY_MS = 2_000;
+
+type KillScope = "internal" | "all";
+
+export interface KillAllDialogProps {
+  sessions: AgentSession[];
+  onComplete?: () => void;
+}
+
+export function KillAllDialog({ sessions, onComplete }: KillAllDialogProps): React.JSX.Element {
+  const [open, setOpen] = useState(false);
+  const [scope, setScope] = useState<KillScope>("internal");
+  const [confirmationInput, setConfirmationInput] = useState("");
+  const [isKilling, setIsKilling] = useState(false);
+  const [completedCount, setCompletedCount] = useState(0);
+  const [targetCount, setTargetCount] = useState(0);
+  const [successCount, setSuccessCount] = useState<number | null>(null);
+  const closeTimeoutRef = useRef<ReturnType<typeof setTimeout> | null>(null);
+
+  const internalSessions = useMemo(
+    () => sessions.filter((session) => session.providerType.toLowerCase() === "internal"),
+    [sessions]
+  );
+
+  const scopedSessions = useMemo(
+    () => (scope === "all" ? sessions : internalSessions),
+    [scope, sessions, internalSessions]
+  );
+
+  const hasConfirmation = confirmationInput === CONFIRM_TEXT;
+  const isConfirmDisabled =
+    isKilling || successCount !== null || !hasConfirmation || scopedSessions.length === 0;
+
+  useEffect((): (() => void) => {
+    return (): void => {
+      if (closeTimeoutRef.current !== null) {
+        clearTimeout(closeTimeoutRef.current);
+      }
+    };
+  }, []);
+
+  const resetState = (): void => {
+    setScope("internal");
+    setConfirmationInput("");
+    setIsKilling(false);
+    setCompletedCount(0);
+    setTargetCount(0);
+    setSuccessCount(null);
+  };
+
+  const handleOpenChange = (nextOpen: boolean): void => {
+    if (!nextOpen && isKilling) {
+      return;
+    }
+
+    if (!nextOpen) {
+      if (closeTimeoutRef.current !== null) {
+        clearTimeout(closeTimeoutRef.current);
+      }
+      resetState();
+    }
+
+    setOpen(nextOpen);
+  };
+
+  const handleKillAll = async (): Promise<void> => {
+    if (isConfirmDisabled) {
+      return;
+    }
+
+    const targetSessions = [...scopedSessions];
+    setIsKilling(true);
+    setCompletedCount(0);
+    setTargetCount(targetSessions.length);
+    setSuccessCount(null);
+
+    const killRequests = targetSessions.map(async (session) => {
+      try {
+        await apiPost<{ message: string }>(`/api/mission-control/sessions/${session.id}/kill`, {
+          force: true,
+        });
+        return true;
+      } catch {
+        return false;
+      } finally {
+        setCompletedCount((currentCount) => currentCount + 1);
+      }
+    });
+
+    const results = await Promise.all(killRequests);
+    const successfulKills = results.filter(Boolean).length;
+
+    setIsKilling(false);
+    setSuccessCount(successfulKills);
+    onComplete?.();
+
+    closeTimeoutRef.current = setTimeout(() => {
+      setOpen(false);
+      resetState();
+    }, AUTO_CLOSE_DELAY_MS);
+  };
+
+  return (
+    <Dialog open={open} onOpenChange={handleOpenChange}>
+      <DialogTrigger asChild>
+        <Button variant="danger" size="sm">
+          Kill All
+        </Button>
+      </DialogTrigger>
+      <DialogContent className="sm:max-w-[520px]">
+        <DialogHeader>
+          <DialogTitle>Kill All Agents</DialogTitle>
+          <DialogDescription>
+            This force-kills every selected agent session. This action cannot be undone.
+          </DialogDescription>
+        </DialogHeader>
+
+        <div className="space-y-4 py-2">
+          <fieldset className="space-y-2">
+            <legend className="text-sm font-medium">Scope</legend>
+            <label className="flex cursor-pointer items-center gap-2 text-sm text-foreground">
+              <input
+                type="radio"
+                name="kill-all-scope"
+                checked={scope === "internal"}
+                disabled={isKilling}
+                onChange={() => {
+                  setScope("internal");
+                }}
+              />
+              <span>Internal provider only ({internalSessions.length})</span>
+            </label>
+            <label className="flex cursor-pointer items-center gap-2 text-sm text-foreground">
+              <input
+                type="radio"
+                name="kill-all-scope"
+                checked={scope === "all"}
+                disabled={isKilling}
+                onChange={() => {
+                  setScope("all");
+                }}
+              />
+              <span>All providers ({sessions.length})</span>
+            </label>
+          </fieldset>
+
+          <div className="space-y-2">
+            <Label htmlFor="kill-all-confirmation-input">Type KILL ALL to confirm</Label>
+            <Input
+              id="kill-all-confirmation-input"
+              value={confirmationInput}
+              onChange={(event: React.ChangeEvent<HTMLInputElement>) => {
+                setConfirmationInput(event.target.value);
+              }}
+              placeholder={CONFIRM_TEXT}
+              autoComplete="off"
+              disabled={isKilling}
+            />
+          </div>
+
+          {scopedSessions.length === 0 ? (
+            <p className="text-sm text-red-500">No sessions in the selected scope.</p>
+          ) : null}
+
+          {isKilling ? (
+            <div className="flex items-center gap-2 text-sm text-muted-foreground">
+              <Loader2 className="h-4 w-4 animate-spin" aria-hidden="true" />
+              <span>
+                Killing {completedCount} of {targetCount} agents...
+              </span>
+            </div>
+          ) : successCount !== null ? (
+            <p className="text-sm text-muted-foreground">
+              Killed {successCount} of {targetCount} agents. Closing...
+            </p>
+          ) : null}
+        </div>
+
+        <DialogFooter>
+          <Button
+            type="button"
+            variant="outline"
+            disabled={isKilling}
+            onClick={() => {
+              setOpen(false);
+            }}
+          >
+            Cancel
+          </Button>
+          <Button
+            type="button"
+            variant="danger"
+            disabled={isConfirmDisabled}
+            onClick={() => {
+              void handleKillAll();
+            }}
+          >
+            Kill All Agents
+          </Button>
+        </DialogFooter>
+      </DialogContent>
+    </Dialog>
+  );
+}

apps/web/src/components/mission-control/MissionControlLayout.tsx

@@ -1,21 +1,86 @@
 "use client";
 
-import { useState } from "react";
+import { useCallback, useState } from "react";
 import { AuditLogDrawer } from "@/components/mission-control/AuditLogDrawer";
 import { GlobalAgentRoster } from "@/components/mission-control/GlobalAgentRoster";
-import { MissionControlPanel } from "@/components/mission-control/MissionControlPanel";
+import {
+  MAX_PANEL_COUNT,
+  MIN_PANEL_COUNT,
+  MissionControlPanel,
+  type PanelConfig,
+} from "@/components/mission-control/MissionControlPanel";
 import { Button } from "@/components/ui/button";
-import { useSessions } from "@/hooks/useMissionControl";
 
-const DEFAULT_PANEL_SLOTS = ["panel-1", "panel-2", "panel-3", "panel-4"] as const;
+const INITIAL_PANELS: PanelConfig[] = [{}];
 
 export function MissionControlLayout(): React.JSX.Element {
-  const { sessions } = useSessions();
+  const [panels, setPanels] = useState<PanelConfig[]>(INITIAL_PANELS);
   const [selectedSessionId, setSelectedSessionId] = useState<string>();
 
-  // First panel: selected session (from roster click) or first available session
+  const handleSelectSession = useCallback((sessionId: string): void => {
-  const firstPanelSessionId = selectedSessionId ?? sessions[0]?.id;
+    setSelectedSessionId(sessionId);
-  const panelSessionIds = [firstPanelSessionId, undefined, undefined, undefined] as const;
+
+    setPanels((currentPanels) => {
+      if (currentPanels.some((panel) => panel.sessionId === sessionId)) {
+        return currentPanels;
+      }
+
+      const firstEmptyPanelIndex = currentPanels.findIndex(
+        (panel) => panel.sessionId === undefined
+      );
+      if (firstEmptyPanelIndex >= 0) {
+        return currentPanels.map((panel, index) =>
+          index === firstEmptyPanelIndex ? { ...panel, sessionId } : panel
+        );
+      }
+
+      if (currentPanels.length >= MAX_PANEL_COUNT) {
+        return currentPanels;
+      }
+
+      return [...currentPanels, { sessionId }];
+    });
+  }, []);
+
+  const handleAddPanel = useCallback((): void => {
+    setPanels((currentPanels) => {
+      if (currentPanels.length >= MAX_PANEL_COUNT) {
+        return currentPanels;
+      }
+
+      return [...currentPanels, {}];
+    });
+  }, []);
+
+  const handleRemovePanel = useCallback((panelIndex: number): void => {
+    setPanels((currentPanels) => {
+      if (panelIndex < 0 || panelIndex >= currentPanels.length) {
+        return currentPanels;
+      }
+
+      if (currentPanels.length <= MIN_PANEL_COUNT) {
+        return currentPanels;
+      }
+
+      const nextPanels = currentPanels.filter((_, index) => index !== panelIndex);
+      return nextPanels.length === 0 ? INITIAL_PANELS : nextPanels;
+    });
+  }, []);
+
+  const handleExpandPanel = useCallback((panelIndex: number): void => {
+    setPanels((currentPanels) => {
+      if (panelIndex < 0 || panelIndex >= currentPanels.length) {
+        return currentPanels;
+      }
+
+      const shouldExpand = !currentPanels[panelIndex]?.expanded;
+
+      return currentPanels.map((panel, index) => ({
+        ...panel,
+        expanded: shouldExpand && index === panelIndex,
+      }));
+    });
+  }, []);
 
   return (
     <section className="flex h-full min-h-0 flex-col overflow-hidden" aria-label="Mission Control">
@@ -32,12 +97,17 @@ export function MissionControlLayout(): React.JSX.Element {
       <div className="grid min-h-0 flex-1 gap-4 xl:grid-cols-[280px_minmax(0,1fr)]">
         <aside className="h-full min-h-0">
           <GlobalAgentRoster
-            onSelectSession={setSelectedSessionId}
+            onSelectSession={handleSelectSession}
             {...(selectedSessionId !== undefined ? { selectedSessionId } : {})}
           />
         </aside>
         <main className="h-full min-h-0 overflow-hidden">
-          <MissionControlPanel panels={DEFAULT_PANEL_SLOTS} panelSessionIds={panelSessionIds} />
+          <MissionControlPanel
+            panels={panels}
+            onAddPanel={handleAddPanel}
+            onRemovePanel={handleRemovePanel}
+            onExpandPanel={handleExpandPanel}
+          />
         </main>
       </div>
     </section>

apps/web/src/components/mission-control/MissionControlPanel.tsx

@@ -1,27 +1,107 @@
 "use client";
 
+import { useEffect } from "react";
 import { OrchestratorPanel } from "@/components/mission-control/OrchestratorPanel";
+import { Button } from "@/components/ui/button";
+
+export interface PanelConfig {
+  sessionId?: string;
+  expanded?: boolean;
+}
 
 interface MissionControlPanelProps {
-  panels: readonly string[];
+  panels: PanelConfig[];
-  panelSessionIds?: readonly (string | undefined)[];
+  onAddPanel: () => void;
+  onRemovePanel: (index: number) => void;
+  onExpandPanel: (index: number) => void;
 }
 
+export const MIN_PANEL_COUNT = 1;
+export const MAX_PANEL_COUNT = 6;
+
 export function MissionControlPanel({
   panels,
-  panelSessionIds,
+  onAddPanel,
+  onRemovePanel,
+  onExpandPanel,
 }: MissionControlPanelProps): React.JSX.Element {
+  const expandedPanelIndex = panels.findIndex((panel) => panel.expanded);
+  const expandedPanel = expandedPanelIndex >= 0 ? panels[expandedPanelIndex] : undefined;
+  const canAddPanel = panels.length < MAX_PANEL_COUNT;
+  const canRemovePanel = panels.length > MIN_PANEL_COUNT;
+
+  useEffect(() => {
+    if (expandedPanelIndex < 0) {
+      return;
+    }
+
+    const handleKeyDown = (event: KeyboardEvent): void => {
+      if (event.key === "Escape") {
+        onExpandPanel(expandedPanelIndex);
+      }
+    };
+
+    window.addEventListener("keydown", handleKeyDown);
+
+    return (): void => {
+      window.removeEventListener("keydown", handleKeyDown);
+    };
+  }, [expandedPanelIndex, onExpandPanel]);
+
   return (
-    <div className="grid h-full min-h-0 auto-rows-fr grid-cols-1 gap-4 overflow-y-auto pr-1 md:grid-cols-2">
+    <div className="flex h-full min-h-0 flex-col gap-3">
-      {panels.map((panelId, index) => {
+      <div className="flex items-center justify-between">
-        const sessionId = panelSessionIds?.[index];
+        <h2 className="text-sm font-medium text-muted-foreground">Panels</h2>
-
+        <Button
-        if (sessionId === undefined) {
+          type="button"
-          return <OrchestratorPanel key={panelId} />;
+          variant="outline"
-        }
+          size="icon"
-
+          onClick={onAddPanel}
-        return <OrchestratorPanel key={panelId} sessionId={sessionId} />;
+          disabled={!canAddPanel}
-      })}
+          aria-label="Add panel"
+          title={canAddPanel ? "Add panel" : "Maximum of 6 panels"}
+        >
+          <span aria-hidden="true" className="text-lg leading-none">
+            +
+          </span>
+        </Button>
+      </div>
+      <div className="min-h-0 flex-1">
+        {expandedPanelIndex >= 0 && expandedPanel ? (
+          <div className="h-full min-h-0">
+            <OrchestratorPanel
+              {...(expandedPanel.sessionId !== undefined
+                ? { sessionId: expandedPanel.sessionId }
+                : {})}
+              onClose={() => {
+                onRemovePanel(expandedPanelIndex);
+              }}
+              closeDisabled={!canRemovePanel}
+              onExpand={() => {
+                onExpandPanel(expandedPanelIndex);
+              }}
+              expanded
+            />
+          </div>
+        ) : (
+          <div className="grid h-full min-h-0 auto-rows-fr grid-cols-1 gap-4 overflow-y-auto pr-1 md:grid-cols-2 xl:grid-cols-3">
+            {panels.map((panel, index) => (
+              <OrchestratorPanel
+                key={`panel-${String(index)}`}
+                {...(panel.sessionId !== undefined ? { sessionId: panel.sessionId } : {})}
+                onClose={() => {
+                  onRemovePanel(index);
+                }}
+                closeDisabled={!canRemovePanel}
+                onExpand={() => {
+                  onExpandPanel(index);
+                }}
+                expanded={panel.expanded ?? false}
+              />
+            ))}
+          </div>
+        )}
+      </div>
     </div>
   );
 }

apps/web/src/components/mission-control/OrchestratorPanel.tsx

@@ -1,13 +1,17 @@
 "use client";
 
-import { useEffect, useRef } from "react";
+import { useEffect, useRef, useState } from "react";
 import { formatDistanceToNow } from "date-fns";
+import { BargeInInput } from "@/components/mission-control/BargeInInput";
 import { Badge } from "@/components/ui/badge";
 import type { BadgeVariant } from "@/components/ui/badge";
+import { Button } from "@/components/ui/button";
 import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
+import { PanelControls } from "@/components/mission-control/PanelControls";
 import { ScrollArea } from "@/components/ui/scroll-area";
 import {
   useSessionStream,
+  useSessions,
   type MissionControlConnectionStatus,
   type MissionControlMessageRole,
 } from "@/hooks/useMissionControl";
@@ -33,6 +37,64 @@ const CONNECTION_TEXT: Record<MissionControlConnectionStatus, string> = {
 
 export interface OrchestratorPanelProps {
   sessionId?: string;
+  onClose?: () => void;
+  closeDisabled?: boolean;
+  onExpand?: () => void;
+  expanded?: boolean;
+}
+
+interface PanelHeaderActionsProps {
+  onClose?: () => void;
+  closeDisabled?: boolean;
+  onExpand?: () => void;
+  expanded?: boolean;
+}
+
+function PanelHeaderActions({
+  onClose,
+  closeDisabled = false,
+  onExpand,
+  expanded = false,
+}: PanelHeaderActionsProps): React.JSX.Element | null {
+  if (!onClose && !onExpand) {
+    return null;
+  }
+
+  return (
+    <div className="flex items-center gap-1">
+      {onExpand ? (
+        <Button
+          type="button"
+          variant="ghost"
+          size="icon"
+          className="h-7 w-7"
+          onClick={onExpand}
+          aria-label={expanded ? "Collapse panel" : "Expand panel"}
+          title={expanded ? "Collapse panel" : "Expand panel"}
+        >
+          <span aria-hidden="true" className="text-base leading-none">
+            {expanded ? "↙" : "↗"}
+          </span>
+        </Button>
+      ) : null}
+      {onClose ? (
+        <Button
+          type="button"
+          variant="ghost"
+          size="icon"
+          className="h-7 w-7"
+          onClick={onClose}
+          disabled={closeDisabled}
+          aria-label="Remove panel"
+          title="Remove panel"
+        >
+          <span aria-hidden="true" className="text-base leading-none">
+            ×
+          </span>
+        </Button>
+      ) : null}
+    </div>
+  );
 }
 
 function formatRelativeTimestamp(timestamp: string): string {
@@ -44,19 +106,43 @@ function formatRelativeTimestamp(timestamp: string): string {
   return formatDistanceToNow(parsedDate, { addSuffix: true });
 }
 
-export function OrchestratorPanel({ sessionId }: OrchestratorPanelProps): React.JSX.Element {
+export function OrchestratorPanel({
+  sessionId,
+  onClose,
+  closeDisabled,
+  onExpand,
+  expanded,
+}: OrchestratorPanelProps): React.JSX.Element {
   const { messages, status, error } = useSessionStream(sessionId ?? "");
+  const { sessions } = useSessions();
   const bottomAnchorRef = useRef<HTMLDivElement | null>(null);
+  const [optimisticStatus, setOptimisticStatus] = useState<string | null>(null);
+
+  const selectedSessionStatus = sessions.find((session) => session.id === sessionId)?.status;
+  const controlsStatus = optimisticStatus ?? selectedSessionStatus ?? "unknown";
+  const panelHeaderActionProps = {
+    ...(onClose !== undefined ? { onClose } : {}),
+    ...(closeDisabled !== undefined ? { closeDisabled } : {}),
+    ...(onExpand !== undefined ? { onExpand } : {}),
+    ...(expanded !== undefined ? { expanded } : {}),
+  };
 
   useEffect(() => {
     bottomAnchorRef.current?.scrollIntoView({ block: "end" });
   }, [messages.length]);
 
+  useEffect(() => {
+    setOptimisticStatus(null);
+  }, [sessionId, selectedSessionStatus]);
+
   if (!sessionId) {
     return (
       <Card className="flex h-full min-h-[220px] flex-col">
         <CardHeader>
-          <CardTitle className="text-base">Orchestrator Panel</CardTitle>
+          <div className="flex items-start justify-between gap-2">
+            <CardTitle className="text-base">Orchestrator Panel</CardTitle>
+            <PanelHeaderActions {...panelHeaderActionProps} />
+          </div>
         </CardHeader>
         <CardContent className="flex flex-1 items-center justify-center text-sm text-muted-foreground">
           Select an agent to view its stream
@@ -68,8 +154,11 @@ export function OrchestratorPanel({ sessionId }: OrchestratorPanelProps): React.
   return (
     <Card className="flex h-full min-h-[220px] flex-col">
       <CardHeader className="space-y-2">
-        <div className="flex items-center justify-between gap-2">
+        <div className="flex items-start justify-between gap-2">
           <CardTitle className="text-base">Orchestrator Panel</CardTitle>
+          <PanelHeaderActions {...panelHeaderActionProps} />
+        </div>
+        <div className="flex flex-col gap-2 sm:flex-row sm:items-start sm:justify-between">
           <div className="flex items-center gap-2 text-xs text-muted-foreground">
             <span
               className={`h-2.5 w-2.5 rounded-full ${CONNECTION_DOT_CLASS[status]} ${
@@ -79,39 +168,49 @@ export function OrchestratorPanel({ sessionId }: OrchestratorPanelProps): React.
             />
             <span>{CONNECTION_TEXT[status]}</span>
           </div>
+          <PanelControls
+            sessionId={sessionId}
+            status={controlsStatus}
+            onStatusChange={setOptimisticStatus}
+          />
         </div>
         <p className="truncate text-xs text-muted-foreground">Session: {sessionId}</p>
       </CardHeader>
-      <CardContent className="flex min-h-0 flex-1 p-0">
+      <CardContent className="flex min-h-0 flex-1 flex-col p-0">
-        <ScrollArea className="h-full w-full">
+        <div className="min-h-0 flex-1">
-          <div className="flex min-h-full flex-col gap-3 p-4">
+          <ScrollArea className="h-full w-full">
-            {messages.length === 0 ? (
+            <div className="flex min-h-full flex-col gap-3 p-4">
-              <p className="mt-6 text-center text-sm text-muted-foreground">
+              {messages.length === 0 ? (
-                {error ?? "Waiting for messages..."}
+                <p className="mt-6 text-center text-sm text-muted-foreground">
-              </p>
+                  {error ?? "Waiting for messages..."}
-            ) : (
+                </p>
-              messages.map((message) => (
+              ) : (
-                <article
+                messages.map((message) => (
-                  key={message.id}
+                  <article
-                  className="rounded-lg border border-border/70 bg-card px-3 py-2"
+                    key={message.id}
-                >
+                    className="rounded-lg border border-border/70 bg-card px-3 py-2"
-                  <div className="mb-2 flex items-center justify-between gap-2">
+                  >
-                    <Badge variant={ROLE_BADGE_VARIANT[message.role]} className="uppercase">
+                    <div className="mb-2 flex items-center justify-between gap-2">
-                      {message.role}
+                      <Badge variant={ROLE_BADGE_VARIANT[message.role]} className="uppercase">
-                    </Badge>
+                        {message.role}
-                    <time className="text-xs text-muted-foreground">
+                      </Badge>
-                      {formatRelativeTimestamp(message.timestamp)}
+                      <time className="text-xs text-muted-foreground">
-                    </time>
+                        {formatRelativeTimestamp(message.timestamp)}
-                  </div>
+                      </time>
-                  <p className="whitespace-pre-wrap break-words text-sm text-foreground">
+                    </div>
-                    {message.content}
+                    <p className="whitespace-pre-wrap break-words text-sm text-foreground">
-                  </p>
+                      {message.content}
-                </article>
+                    </p>
-              ))
+                  </article>
-            )}
+                ))
-            <div ref={bottomAnchorRef} />
+              )}
-          </div>
+              <div ref={bottomAnchorRef} />
-        </ScrollArea>
+            </div>
+          </ScrollArea>
+        </div>
+        <div className="border-t border-border/70 p-3">
+          <BargeInInput sessionId={sessionId} />
+        </div>
       </CardContent>
     </Card>
   );

apps/web/src/components/mission-control/PanelControls.tsx

@@ -0,0 +1,259 @@
+"use client";
+
+import { useEffect, useState } from "react";
+import { useMutation, useQueryClient } from "@tanstack/react-query";
+import { Loader2 } from "lucide-react";
+import { Badge } from "@/components/ui/badge";
+import { Button } from "@/components/ui/button";
+import { apiPost } from "@/lib/api/client";
+
+const SESSIONS_QUERY_KEY = ["mission-control", "sessions"] as const;
+
+type PanelAction = "pause" | "resume" | "graceful-kill" | "force-kill";
+type KillConfirmationState = "graceful" | "force" | null;
+
+interface PanelActionResult {
+  nextStatus: string;
+}
+
+export interface PanelControlsProps {
+  sessionId: string;
+  // eslint-disable-next-line @typescript-eslint/no-redundant-type-constituents
+  status: "active" | "paused" | "killed" | string;
+  onStatusChange?: (newStatus: string) => void;
+}
+
+function getErrorMessage(error: unknown): string {
+  if (error instanceof Error && error.message.trim().length > 0) {
+    return error.message;
+  }
+
+  return "Failed to update agent session.";
+}
+
+export function PanelControls({
+  sessionId,
+  status,
+  onStatusChange,
+}: PanelControlsProps): React.JSX.Element {
+  const queryClient = useQueryClient();
+  const [errorMessage, setErrorMessage] = useState<string | null>(null);
+  const [confirmingKill, setConfirmingKill] = useState<KillConfirmationState>(null);
+
+  useEffect(() => {
+    setErrorMessage(null);
+    setConfirmingKill(null);
+  }, [sessionId]);
+
+  const controlMutation = useMutation({
+    mutationFn: async (action: PanelAction): Promise<PanelActionResult> => {
+      switch (action) {
+        case "pause":
+          await apiPost<{ message: string }>(
+            `/api/mission-control/sessions/${encodeURIComponent(sessionId)}/pause`
+          );
+          return { nextStatus: "paused" };
+        case "resume":
+          await apiPost<{ message: string }>(
+            `/api/mission-control/sessions/${encodeURIComponent(sessionId)}/resume`
+          );
+          return { nextStatus: "active" };
+        case "graceful-kill":
+          await apiPost<{ message: string }>(
+            `/api/mission-control/sessions/${encodeURIComponent(sessionId)}/kill`,
+            { force: false }
+          );
+          return { nextStatus: "killed" };
+        case "force-kill":
+          await apiPost<{ message: string }>(
+            `/api/mission-control/sessions/${encodeURIComponent(sessionId)}/kill`,
+            { force: true }
+          );
+          return { nextStatus: "killed" };
+      }
+    },
+    onSuccess: ({ nextStatus }): void => {
+      setErrorMessage(null);
+      setConfirmingKill(null);
+      onStatusChange?.(nextStatus);
+      void queryClient.invalidateQueries({ queryKey: SESSIONS_QUERY_KEY });
+    },
+    onError: (error: unknown): void => {
+      setConfirmingKill(null);
+      setErrorMessage(getErrorMessage(error));
+    },
+  });
+
+  const normalizedStatus = status.toLowerCase();
+  const isKilled = normalizedStatus === "killed";
+  const isBusy = controlMutation.isPending;
+  const pendingAction = isBusy ? controlMutation.variables : undefined;
+
+  const submitAction = (action: PanelAction): void => {
+    setErrorMessage(null);
+    controlMutation.mutate(action);
+  };
+
+  const pauseDisabled = isBusy || normalizedStatus === "paused" || isKilled;
+  const resumeDisabled = isBusy || normalizedStatus === "active" || isKilled;
+  const gracefulKillDisabled = isBusy || isKilled;
+  const forceKillDisabled = isBusy || isKilled;
+
+  return (
+    <div className="flex flex-col items-end gap-2">
+      <div className="flex flex-wrap items-center justify-end gap-1.5">
+        <Button
+          type="button"
+          size="sm"
+          variant="secondary"
+          onClick={() => {
+            submitAction("pause");
+          }}
+          disabled={pauseDisabled}
+          aria-label="Pause session"
+        >
+          {pendingAction === "pause" ? (
+            <Loader2 className="h-3.5 w-3.5 animate-spin" aria-hidden="true" />
+          ) : (
+            <span aria-hidden="true">⏸</span>
+          )}
+          <span>Pause</span>
+        </Button>
+
+        <Button
+          type="button"
+          size="sm"
+          variant="secondary"
+          onClick={() => {
+            submitAction("resume");
+          }}
+          disabled={resumeDisabled}
+          aria-label="Resume session"
+        >
+          {pendingAction === "resume" ? (
+            <Loader2 className="h-3.5 w-3.5 animate-spin" aria-hidden="true" />
+          ) : (
+            <span aria-hidden="true">▶</span>
+          )}
+          <span>Resume</span>
+        </Button>
+
+        <div className="relative">
+          <Button
+            type="button"
+            size="sm"
+            variant="secondary"
+            onClick={() => {
+              setErrorMessage(null);
+              setConfirmingKill((current) => (current === "graceful" ? null : "graceful"));
+            }}
+            disabled={gracefulKillDisabled}
+            aria-label="Gracefully kill session"
+          >
+            {pendingAction === "graceful-kill" ? (
+              <Loader2 className="h-3.5 w-3.5 animate-spin" aria-hidden="true" />
+            ) : (
+              <span aria-hidden="true">⏹</span>
+            )}
+            <span>Graceful Kill</span>
+          </Button>
+          {confirmingKill === "graceful" ? (
+            <div className="absolute right-0 top-[calc(100%+0.375rem)] z-20 w-72 rounded-md border border-border bg-card p-2 shadow-lg">
+              <p className="text-xs text-muted-foreground">
+                Gracefully stop this agent after it finishes the current step?
+              </p>
+              <div className="mt-2 flex justify-end gap-1.5">
+                <Button
+                  type="button"
+                  size="sm"
+                  variant="ghost"
+                  onClick={() => {
+                    setConfirmingKill(null);
+                  }}
+                  disabled={isBusy}
+                >
+                  Cancel
+                </Button>
+                <Button
+                  type="button"
+                  size="sm"
+                  variant="secondary"
+                  onClick={() => {
+                    submitAction("graceful-kill");
+                  }}
+                  disabled={isBusy}
+                >
+                  {pendingAction === "graceful-kill" ? (
+                    <Loader2 className="h-3.5 w-3.5 animate-spin" aria-hidden="true" />
+                  ) : null}
+                  <span>Confirm</span>
+                </Button>
+              </div>
+            </div>
+          ) : null}
+        </div>
+
+        <div className="relative">
+          <Button
+            type="button"
+            size="sm"
+            variant="danger"
+            onClick={() => {
+              setErrorMessage(null);
+              setConfirmingKill((current) => (current === "force" ? null : "force"));
+            }}
+            disabled={forceKillDisabled}
+            aria-label="Force kill session"
+          >
+            {pendingAction === "force-kill" ? (
+              <Loader2 className="h-3.5 w-3.5 animate-spin" aria-hidden="true" />
+            ) : (
+              <span aria-hidden="true">💀</span>
+            )}
+            <span>Force Kill</span>
+          </Button>
+          {confirmingKill === "force" ? (
+            <div className="absolute right-0 top-[calc(100%+0.375rem)] z-20 w-72 rounded-md border border-border bg-card p-2 shadow-lg">
+              <p className="text-xs text-muted-foreground">
+                This will hard-kill the agent immediately.
+              </p>
+              <div className="mt-2 flex justify-end gap-1.5">
+                <Button
+                  type="button"
+                  size="sm"
+                  variant="ghost"
+                  onClick={() => {
+                    setConfirmingKill(null);
+                  }}
+                  disabled={isBusy}
+                >
+                  Cancel
+                </Button>
+                <Button
+                  type="button"
+                  size="sm"
+                  variant="danger"
+                  onClick={() => {
+                    submitAction("force-kill");
+                  }}
+                  disabled={isBusy}
+                >
+                  {pendingAction === "force-kill" ? (
+                    <Loader2 className="h-3.5 w-3.5 animate-spin" aria-hidden="true" />
+                  ) : null}
+                  <span>Confirm</span>
+                </Button>
+              </div>
+            </div>
+          ) : null}
+        </div>
+      </div>
+
+      {errorMessage ? (
+        <Badge variant="status-error" className="max-w-[32rem] whitespace-normal text-xs">
+          {errorMessage}
+        </Badge>
+      ) : null}
+    </div>
+  );
+}