diff --git a/src/pipeline/steps/fetch.test.ts b/src/pipeline/steps/fetch.test.ts
new file mode 100644
index 00000000..8b97b313
--- /dev/null
+++ b/src/pipeline/steps/fetch.test.ts
@@ -0,0 +1,179 @@
+import { afterEach, describe, expect, it, vi } from 'vitest';
+import { CliError } from '../../errors.js';
+import type { IPage } from '../../types.js';
+import { stepFetch } from './fetch.js';
+
+afterEach(() => {
+  vi.restoreAllMocks();
+  vi.unstubAllGlobals();
+});
+
+describe('stepFetch', () => {
+  // W1 + W4: non-browser single fetch throws CliError with FETCH_ERROR code and full message
+  it('throws CliError with FETCH_ERROR code on non-ok responses without a browser session', async () => {
+    const jsonMock = vi.fn().mockResolvedValue({ error: 'rate limited' });
+    const fetchMock = vi.fn().mockResolvedValue({
+      ok: false,
+      status: 429,
+      statusText: 'Too Many Requests',
+      json: jsonMock,
+    });
+    vi.stubGlobal('fetch', fetchMock);
+
+    const err = await stepFetch(null, { url: 'https://api.example.com/items' }, null, {}).catch((e: unknown) => e);
+    expect(err).toBeInstanceOf(CliError);
+    expect((err as CliError).code).toBe('FETCH_ERROR');
+    expect((err as CliError).message).toBe('HTTP 429 Too Many Requests from https://api.example.com/items');
+    expect(jsonMock).not.toHaveBeenCalled();
+  });
+
+  // W1 + W3: browser single fetch returns error status from evaluate, outer code throws CliError
+  it('throws CliError with FETCH_ERROR code on non-ok responses inside the browser session', async () => {
+    const jsonMock = vi.fn().mockResolvedValue({ error: 'auth required' });
+    const fetchMock = vi.fn().mockResolvedValue({
+      ok: false,
+      status: 401,
+      statusText: 'Unauthorized',
+      json: jsonMock,
+    });
+    vi.stubGlobal('fetch', fetchMock);
+
+    // Simulate real CDP behavior: evaluate returns a value, errors are thrown outside
+    const page = {
+      evaluate: vi.fn(async (js: string) => Function(`return (${js})`)()()),
+    } as unknown as IPage;
+
+    const err = await stepFetch(page, { url: 'https://api.example.com/items' }, null, {}).catch((e: unknown) => e);
+    expect(err).toBeInstanceOf(CliError);
+    expect((err as CliError).code).toBe('FETCH_ERROR');
+    expect((err as CliError).message).toBe('HTTP 401 Unauthorized from https://api.example.com/items');
+    expect(jsonMock).not.toHaveBeenCalled();
+  });
+
+  it('returns per-item HTTP errors for batch fetches without a browser session', async () => {
+    const jsonMock = vi.fn().mockResolvedValue({ error: 'upstream unavailable' });
+    const fetchMock = vi.fn().mockResolvedValue({
+      ok: false,
+      status: 503,
+      statusText: 'Service Unavailable',
+      json: jsonMock,
+    });
+    vi.stubGlobal('fetch', fetchMock);
+
+    await expect(stepFetch(
+      null,
+      { url: 'https://api.example.com/items/${{ item.id }}' },
+      [{ id: 1 }],
+      {},
+    )).resolves.toEqual([
+      { error: 'HTTP 503 Service Unavailable from https://api.example.com/items/1' },
+    ]);
+    expect(jsonMock).not.toHaveBeenCalled();
+  });
+
+  it('returns per-item HTTP errors for batch browser fetches', async () => {
+    const jsonMock = vi.fn().mockResolvedValue({ error: 'upstream unavailable' });
+    const fetchMock = vi.fn().mockResolvedValue({
+      ok: false,
+      status: 503,
+      statusText: 'Service Unavailable',
+      json: jsonMock,
+    });
+    vi.stubGlobal('fetch', fetchMock);
+
+    const page = {
+      evaluate: vi.fn(async (js: string) => Function(`return (${js})`)()()),
+    } as unknown as IPage;
+
+    await expect(stepFetch(
+      page,
+      { url: 'https://api.example.com/items/${{ item.id }}' },
+      [{ id: 1 }],
+      {},
+    )).resolves.toEqual([
+      { error: 'HTTP 503 Service Unavailable from https://api.example.com/items/1' },
+    ]);
+    expect(jsonMock).not.toHaveBeenCalled();
+  });
+
+  it('stringifies non-Error batch browser failures consistently', async () => {
+    vi.stubGlobal('fetch', vi.fn().mockRejectedValue('socket hang up'));
+
+    const page = {
+      evaluate: vi.fn(async (js: string) => Function(`return (${js})`)()()),
+    } as unknown as IPage;
+
+    await expect(stepFetch(
+      page,
+      { url: 'https://api.example.com/items/${{ item.id }}' },
+      [{ id: 1 }],
+      {},
+    )).resolves.toEqual([
+      { error: 'socket hang up' },
+    ]);
+  });
+
+  it('stringifies non-Error batch non-browser failures consistently', async () => {
+    vi.stubGlobal('fetch', vi.fn().mockRejectedValue('socket hang up'));
+
+    await expect(stepFetch(
+      null,
+      { url: 'https://api.example.com/items/${{ item.id }}' },
+      [{ id: 1 }],
+      {},
+    )).resolves.toEqual([
+      { error: 'socket hang up' },
+    ]);
+  });
+
+  // W2: batch item failures emit a warning log
+  it('logs a warning for each failed batch item in non-browser mode', async () => {
+    const { log } = await import('../../logger.js');
+    const warnSpy = vi.spyOn(log, 'warn');
+
+    vi.stubGlobal('fetch', vi.fn().mockResolvedValue({
+      ok: false,
+      status: 503,
+      statusText: 'Service Unavailable',
+      json: vi.fn(),
+    }));
+
+    await stepFetch(
+      null,
+      { url: 'https://api.example.com/items/${{ item.id }}' },
+      [{ id: 1 }, { id: 2 }],
+      {},
+    );
+
+    expect(warnSpy).toHaveBeenCalledTimes(2);
+    expect(warnSpy).toHaveBeenCalledWith(expect.stringContaining('https://api.example.com/items/1'));
+    expect(warnSpy).toHaveBeenCalledWith(expect.stringContaining('https://api.example.com/items/2'));
+  });
+
+  it('logs a warning for each failed batch item in browser mode', async () => {
+    const { log } = await import('../../logger.js');
+    const warnSpy = vi.spyOn(log, 'warn');
+
+    vi.stubGlobal('fetch', vi.fn().mockResolvedValue({
+      ok: false,
+      status: 502,
+      statusText: 'Bad Gateway',
+      json: vi.fn(),
+    }));
+
+    const page = {
+      evaluate: vi.fn(async (js: string) => Function(`return (${js})`)()()),
+    } as unknown as IPage;
+
+    await stepFetch(
+      page,
+      { url: 'https://api.example.com/items/${{ item.id }}' },
+      [{ id: 1 }, { id: 2 }],
+      {},
+    );
+
+    expect(warnSpy).toHaveBeenCalledTimes(2);
+    expect(warnSpy).toHaveBeenCalledWith(expect.stringContaining('https://api.example.com/items/1'));
+    expect(warnSpy).toHaveBeenCalledWith(expect.stringContaining('https://api.example.com/items/2'));
+  });
+});
diff --git a/src/pipeline/steps/fetch.ts b/src/pipeline/steps/fetch.ts
index a771bb35..edecda63 100644
--- a/src/pipeline/steps/fetch.ts
+++ b/src/pipeline/steps/fetch.ts
@@ -2,6 +2,8 @@
  * Pipeline step: fetch — HTTP API requests.
  */
 
+import { CliError, getErrorMessage } from '../../errors.js';
+import { log } from '../../logger.js';
 import type { IPage } from '../../types.js';
 import { render } from '../template.js';
 
@@ -28,20 +30,33 @@ async function fetchSingle(
 
   if (page === null) {
     const resp = await fetch(finalUrl, { method: method.toUpperCase(), headers: renderedHeaders });
+    if (!resp.ok) {
+      throw new CliError('FETCH_ERROR', `HTTP ${resp.status} ${resp.statusText} from ${finalUrl}`);
+    }
     return resp.json();
   }
 
   const headersJs = JSON.stringify(renderedHeaders);
   const urlJs = JSON.stringify(finalUrl);
   const methodJs = JSON.stringify(method.toUpperCase());
-  return page.evaluate(`
+  // Return error status instead of throwing inside evaluate to avoid CDP wrapper
+  // rewriting the message (CDP prepends "Evaluate error: " to thrown errors).
+  const result = await page.evaluate(`
     async () => {
       const resp = await fetch(${urlJs}, {
         method: ${methodJs}, headers: ${headersJs}, credentials: "include"
       });
+      if (!resp.ok) {
+        return { __httpError: resp.status, statusText: resp.statusText };
+      }
       return await resp.json();
     }
   `);
+  if (result && typeof result === 'object' && '__httpError' in result) {
+    const { __httpError: status, statusText } = result as { __httpError: number; statusText: string };
+    throw new CliError('FETCH_ERROR', `HTTP ${status} ${statusText} from ${finalUrl}`);
+  }
+  return result;
 }
 
 /**
@@ -71,9 +86,13 @@ async function fetchBatchInBrowser(
           const i = idx++;
           try {
             const resp = await fetch(urls[i], { method, headers, credentials: "include" });
+            if (!resp.ok) {
+              throw new Error('HTTP ' + resp.status + ' ' + resp.statusText + ' from ' + urls[i]);
+            }
             results[i] = await resp.json();
           } catch (e) {
-            results[i] = { error: e.message };
+            results[i] = { error: e instanceof Error ? e.message : String(e) };
+            // Note: getErrorMessage() is a Node.js utility — can't use it inside evaluate()
           }
         }
       }
@@ -114,13 +133,26 @@ export async function stepFetch(page: IPage | null, params: unknown, data: unkno
 
     // BATCH IPC: if browser is available, batch all fetches into a single evaluate() call
     if (page !== null) {
-      return fetchBatchInBrowser(page, urls, method.toUpperCase(), renderedHeaders, concurrency);
+      const results = await fetchBatchInBrowser(page, urls, method.toUpperCase(), renderedHeaders, concurrency);
+      for (let i = 0; i < results.length; i++) {
+        const r = results[i];
+        if (r && typeof r === 'object' && 'error' in r) {
+          log.warn(`Batch fetch failed for ${urls[i]}: ${(r as { error: string }).error}`);
+        }
+      }
+      return results;
     }
 
     // Non-browser: use concurrent pool (already optimized)
     return mapConcurrent(data, concurrency, async (item, index) => {
       const itemUrl = String(render(urlTemplate, { args, data, item, index }));
-      return fetchSingle(null, itemUrl, method, queryParams, headers, args, data);
+      try {
+        return await fetchSingle(null, itemUrl, method, queryParams, headers, args, data);
+      } catch (error) {
+        const message = getErrorMessage(error);
+        log.warn(`Batch fetch failed for ${itemUrl}: ${message}`);
+        return { error: message };
+      }
     });
   }
   const url = render(urlOrObj, { args, data });