fix(network): always render Response Body section, note streaming

Streaming responses (text/event-stream, application/x-ndjson, POST to
/mcp) are intentionally not body-captured by the fetch tracker, so the
section was silently omitted. Now whenever a response was received we
render the section, with either the body, a "(empty)" note, or a
"Streaming response — body not captured" note keyed off content-type.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: cliffhall

clients/web/src/components/groups/NetworkEntry/NetworkEntry.stories.tsx

@@ -57,6 +57,28 @@ const errorEntry: FetchRequestEntry = {
   category: "transport",
 };
 
+const streamingEntry: FetchRequestEntry = {
+  id: "n-stream",
+  timestamp: new Date("2026-03-17T10:30:12Z"),
+  method: "POST",
+  url: "http://localhost:3000/mcp",
+  requestHeaders: {
+    accept: "application/json, text/event-stream",
+    "content-type": "application/json",
+    "mcp-session-id": "0a0b0a5-fd27-4c95-a805-c0fba67e00fb",
+  },
+  requestBody: '{"method":"resources/templates/list","jsonrpc":"2.0","id":4}',
+  responseStatus: 200,
+  responseStatusText: "OK",
+  responseHeaders: {
+    "cache-control": "no-cache",
+    "content-type": "text/event-stream",
+    "mcp-session-id": "0a0b0a5-fd27-4c95-a805-c0fba67e00fb",
+  },
+  duration: 26,
+  category: "transport",
+};
+
 const transportError: FetchRequestEntry = {
   id: "n-4",
   timestamp: new Date("2026-03-17T10:30:15Z"),
@@ -83,6 +105,10 @@ export const HttpError: Story = {
   args: { entry: errorEntry, isListExpanded: true },
 };
 
+export const StreamingResponse: Story = {
+  args: { entry: streamingEntry, isListExpanded: true },
+};
+
 export const FetchError: Story = {
   args: { entry: transportError, isListExpanded: true },
 };

clients/web/src/components/groups/NetworkEntry/NetworkEntry.test.tsx

@@ -110,6 +110,49 @@ describe("NetworkEntry", () => {
     expect(screen.getAllByText("(none)").length).toBe(2);
   });
 
+  it("shows a 'streaming' placeholder when responseBody is missing but content-type is SSE", async () => {
+    const user = userEvent.setup();
+    const sse: FetchRequestEntry = {
+      ...baseEntry,
+      responseHeaders: { "content-type": "text/event-stream" },
+      responseBody: undefined,
+    };
+    renderWithMantine(<NetworkEntry entry={sse} isListExpanded={false} />);
+    await user.click(screen.getByRole("button", { name: "Expand" }));
+    expect(screen.getByText("Response Body")).toBeInTheDocument();
+    expect(
+      screen.getByText(/Streaming response — body not captured/),
+    ).toBeInTheDocument();
+  });
+
+  it("shows '(empty)' for a non-streaming response with no body", async () => {
+    const user = userEvent.setup();
+    const empty: FetchRequestEntry = {
+      ...baseEntry,
+      responseHeaders: { "content-type": "application/json" },
+      responseBody: undefined,
+    };
+    renderWithMantine(<NetworkEntry entry={empty} isListExpanded={false} />);
+    await user.click(screen.getByRole("button", { name: "Expand" }));
+    expect(screen.getByText("Response Body")).toBeInTheDocument();
+    expect(screen.getByText("(empty)")).toBeInTheDocument();
+  });
+
+  it("omits the Response Body section entirely when no response was received", async () => {
+    const user = userEvent.setup();
+    const pending: FetchRequestEntry = {
+      ...baseEntry,
+      responseStatus: undefined,
+      responseStatusText: undefined,
+      responseHeaders: undefined,
+      responseBody: undefined,
+      duration: undefined,
+    };
+    renderWithMantine(<NetworkEntry entry={pending} isListExpanded={false} />);
+    await user.click(screen.getByRole("button", { name: "Expand" }));
+    expect(screen.queryByText("Response Body")).not.toBeInTheDocument();
+  });
+
   it("shows a 'too large' notice when a body exceeds the inline preview limit", async () => {
     const user = userEvent.setup();
     const huge = "x".repeat(5000);

clients/web/src/components/groups/NetworkEntry/NetworkEntry.tsx

@@ -83,6 +83,14 @@ function categoryColor(category: FetchRequestEntry["category"]): string {
   return category === "auth" ? "violet" : "blue";
 }
 
+function isStreamingResponse(entry: FetchRequestEntry): boolean {
+  const contentType = entry.responseHeaders?.["content-type"] ?? "";
+  return (
+    contentType.includes("text/event-stream") ||
+    contentType.includes("application/x-ndjson")
+  );
+}
+
 function HeadersTable({ headers }: { headers: Record<string, string> }) {
   const rows = Object.entries(headers);
   if (rows.length === 0) {
@@ -184,12 +192,20 @@ export function NetworkEntry({ entry, isListExpanded }: NetworkEntryProps) {
                 <HeadersTable headers={entry.responseHeaders} />
               </Stack>
             )}
-            {entry.responseBody && (
+            {entry.responseStatus !== undefined && (
               <Stack gap="xs">
                 <Text size="sm" fw={500}>
                   Response Body
                 </Text>
-                <BodyPreview body={entry.responseBody} />
+                {entry.responseBody ? (
+                  <BodyPreview body={entry.responseBody} />
+                ) : (
+                  <Text size="xs" c="dimmed">
+                    {isStreamingResponse(entry)
+                      ? "Streaming response — body not captured"
+                      : "(empty)"}
+                  </Text>
+                )}
               </Stack>
             )}
             {entry.error && (