diff --git a/src/routes/containers/+page.svelte b/src/routes/containers/+page.svelte
index f890a26..a0663b9 100644
--- a/src/routes/containers/+page.svelte
+++ b/src/routes/containers/+page.svelte
@@ -134,6 +134,9 @@
 
 	// Derived: current environment details for reactive port URL generation
 	const currentEnvDetails = $derived($environments.find(e => e.id === $currentEnvironment?.id) ?? null);
+	// hawser-edge exposes an exec-only terminal protocol (the agent has no attach path),
+	// so don't offer Attach there - the server would reject it anyway.
+	const attachSupported = $derived(currentEnvDetails?.connectionType !== 'hawser-edge');
 
 	// Search and sort state - initialize from URL for persistence across navigation
 	const initialSearch = $page.url.searchParams.get('search')
@@ -1124,23 +1127,22 @@
 			const savedUser = getSavedUser(container.id);
 			terminalUser = savedUser ?? 'root';
 			terminalCustomUsers = getCustomUsers();
-			// Default a fresh session to exec so a prior container's Attach choice
-			// (terminalMode is shared) doesn't carry over to this one.
-			terminalMode = 'exec';
 			// Show popover to configure new terminal
 			terminalPopoverStates[container.id] = true;
 		}
 	}
 
 	function startTerminal(container: ContainerInfo) {
-		if (terminalMode === 'exec') saveUserForContainer(container.id, terminalUser);
+		// Edge is exec-only; never start an attach session there even if a stale mode lingers.
+		const mode: TerminalMode = attachSupported ? terminalMode : 'exec';
+		if (mode === 'exec') saveUserForContainer(container.id, terminalUser);
 		terminalCustomUsers = getCustomUsers();
 		const terminal: ActiveTerminal = {
 			containerId: container.id,
 			containerName: container.name,
 			shell: terminalShell,
 			user: terminalUser,
-			mode: terminalMode
+			mode
 		};
 		activeTerminals = [...activeTerminals, terminal];
 		currentTerminalContainerId = container.id;
@@ -2167,7 +2169,15 @@
 							{:else}
 								<Popover.Root open={terminalPopoverStates[container.id] ?? false} onOpenChange={(open) => {
 									terminalPopoverStates[container.id] = open;
-									if (open && terminalMode === 'exec') detectContainerShells(container.id);
+									if (open) {
+										// Default each freshly-opened session to exec so a prior container's
+										// Attach choice (terminalMode is shared) doesn't carry over, and the
+										// picker/shell controls always render. Restore this container's saved user.
+										terminalMode = 'exec';
+										terminalUser = getSavedUser(container.id) ?? 'root';
+										terminalCustomUsers = getCustomUsers();
+										detectContainerShells(container.id);
+									}
 								}}>
 									<Popover.Trigger
 										onclick={(e: MouseEvent) => e.stopPropagation()}
@@ -2195,6 +2205,8 @@
 											</div>
 										{:else}
 											<div class="p-3 space-y-3">
+												<!-- Mode picker only when attach is possible; edge is exec-only, so it's hidden there. -->
+												{#if attachSupported}
 												<div class="space-y-1.5">
 													<Label class="text-xs">Mode</Label>
 													<Select.Root type="single" value={terminalMode} onValueChange={(value) => {
@@ -2222,6 +2234,7 @@
 														</Select.Content>
 													</Select.Root>
 													</div>
+												{/if}
 													{#if terminalMode === 'exec'}
 														<div class="space-y-1.5">
 															<Label class="text-xs">Shell</Label>
diff --git a/src/routes/terminal/+page.svelte b/src/routes/terminal/+page.svelte
index 32e9e46..6c8b27f 100644
--- a/src/routes/terminal/+page.svelte
+++ b/src/routes/terminal/+page.svelte
@@ -33,6 +33,11 @@
 	let shellDetection = $state<ShellDetectionResult | null>(null);
 	let detectingShells = $state(false);
 
+	// hawser-edge exposes an exec-only terminal protocol, so attach isn't offered there.
+	const attachSupported = $derived(
+		($environments.find(e => e.id === $currentEnvironment?.id)?.connectionType ?? 'socket') !== 'hawser-edge'
+	);
+
 	// Shell/user options
 	let terminalMode = $state<TerminalMode>('exec');
 	let selectedShell = $state('/bin/bash');
@@ -216,7 +221,7 @@
 
 	onMount(async () => {
 		customUsers = getCustomUsers();
-		if ($page.url.searchParams.get('mode') === 'attach') {
+		if ($page.url.searchParams.get('mode') === 'attach' && attachSupported) {
 			terminalMode = 'attach';
 		}
 		await fetchContainers();
@@ -311,6 +316,8 @@
 				</div>
 			{/if}
 		</div>
+		<!-- Mode picker only when attach is possible; edge is exec-only, so it's hidden there. -->
+		{#if attachSupported}
 		<div class="flex items-center gap-2">
 			<Label class="text-sm text-muted-foreground">Mode:</Label>
 			<Select.Root type="single" value={terminalMode} onValueChange={(value) => terminalMode = value as TerminalMode}>
@@ -335,6 +342,7 @@
 				</Select.Content>
 			</Select.Root>
 		</div>
+		{/if}
 
 		{#if selectedContainer}
 			<Button size="sm" variant="ghost" onclick={clearSelection} class="h-9 px-3 text-sm text-muted-foreground hover:text-foreground">
@@ -536,7 +544,7 @@
 						containerName={selectedContainer.name}
 						shell={selectedShell}
 						user={committedUser}
-						mode={terminalMode}
+						mode={attachSupported ? terminalMode : 'exec'}
 						{envId}
 						fontSize={terminalFontSize}
 					/>
diff --git a/tests/docker-stream-core.test.ts b/tests/docker-stream-core.test.ts
index 114aae4..92c5da3 100644
--- a/tests/docker-stream-core.test.ts
+++ b/tests/docker-stream-core.test.ts
@@ -70,6 +70,38 @@ describe('processDockerStreamChunk - multiplexed (non-TTY attach) stream', () =>
 		// subsequent bytes now pass through raw
 		expect(processDockerStreamChunk(Buffer.from('more'), st).join('')).toBe('more');
 	});
+
+	test('an oversized frame size (>10MB) trips the raw fallback', () => {
+		const st = createDockerStreamState(true);
+		const header = Buffer.alloc(8);
+		header.writeUInt8(1, 0);
+		header.writeUInt32BE(20 * 1024 * 1024, 4); // 20 MB - beyond the 10 MB cap
+		const out = processDockerStreamChunk(Buffer.concat([Buffer.from(HTTP_HEAD), header, Buffer.from('body')]), st);
+		expect(out.join('')).toContain('body');
+		expect(st.multiplexed).toBe(false);
+	});
+});
+
+describe('processDockerStreamChunk - chunked AND multiplexed together (non-TTY attach over chunked HTTP)', () => {
+	test('demuxes frames delivered inside chunked bodies, across a chunk seam', () => {
+		const st = createDockerStreamState(true);
+		const f = frame(1, 'hello');
+		// two frames' bytes split into chunks so a frame boundary straddles a chunk boundary
+		const payload = Buffer.concat([f, frame(2, 'world')]);
+		const c1 = payload.slice(0, 6);   // mid-first-frame
+		const c2 = payload.slice(6);
+		const body =
+			c1.length.toString(16) + '\r\n' ; // chunk-size line for c1
+		// first event: HTTP head (chunked) + first chunk header+data, no trailing frame complete
+		const first = Buffer.concat([Buffer.from(HTTP_HEAD_CHUNKED + body), c1, Buffer.from('\r\n')]);
+		const secondBody = c2.length.toString(16) + '\r\n';
+		const second = Buffer.concat([Buffer.from(secondBody), c2, Buffer.from('\r\n')]);
+		const out = [
+			...processDockerStreamChunk(first, st),
+			...processDockerStreamChunk(second, st)
+		];
+		expect(out.join('')).toBe('helloworld');
+	});
 });
 
 describe('decodeChunkedDockerBody', () => {