diff --git a/.coderabbit.yaml b/.coderabbit.yaml
index 64cc6dd..47ef52d 100644
--- a/.coderabbit.yaml
+++ b/.coderabbit.yaml
@@ -30,6 +30,7 @@ reviews:
   in_progress_fortune: false
   poem: false
 
+
   # Path filters to focus on important files
   path_filters:
     # Source code
@@ -88,6 +89,7 @@ reviews:
         13. Use type hints for all function parameters and return values
         14. Use structured logging with context and appropriate log levels.
         15. Log message strings should be plain English without `_()` (TranslatingLogger handles translation); wrap non-log user-facing strings with `_()` and add translations
+        16. NEVER flag PEP 8 whitespace/spacing issues (autopep8 handles these automatically via pdm run format)
     - path: "tests/**/*.py"
       instructions: |
         TESTING RULES:
@@ -106,6 +108,7 @@ reviews:
         13. Focus on minimal health checks, not full user workflows
         14. Include SPDX license headers
         15. Use descriptive test names in English
+        16. NEVER flag PEP 8 whitespace/spacing issues (autopep8 handles these automatically via pdm run format)
     - path: "scripts/**/*.py"
       instructions: |
         SCRIPT RULES:
diff --git a/docs/CONFIGURATION.md b/docs/CONFIGURATION.md
index 161c176..a6c53f4 100644
--- a/docs/CONFIGURATION.md
+++ b/docs/CONFIGURATION.md
@@ -220,15 +220,27 @@ login:
 
 ### diagnostics
 
-Diagnostics configuration for troubleshooting login detection issues.
+Diagnostics configuration for troubleshooting login detection issues and publish failures.
 
 ```yaml
 diagnostics:
-  login_detection_capture: false       # Capture screenshot + HTML when login state is UNKNOWN
+  capture_on:
+    login_detection: false      # Capture screenshot + HTML when login state is UNKNOWN
+    publish: false             # Capture screenshot + HTML + JSON on each failed publish attempt (timeouts/protocol errors)
+  capture_log_copy: false       # Copy entire bot log file when diagnostics are captured (may duplicate log content)
   pause_on_login_detection_failure: false  # Pause for manual inspection (interactive only)
-  output_dir: ""                       # Custom output directory (default: portable .temp/diagnostics, xdg cache/diagnostics)
+  output_dir: ""               # Custom output directory (see "Output locations (default)" below)
 ```
 
+**Migration Note:**
+
+Old diagnostics keys have been renamed/moved. Update configs and CI/automation accordingly:
+
+- `login_detection_capture` → `capture_on.login_detection`
+- `publish_error_capture` → `capture_on.publish`
+
+`capture_log_copy` is a new top-level flag. It may copy the same log multiple times during a single run if multiple diagnostic events are triggered.
+
 **Login Detection Behavior:**
 
 The bot uses a layered approach to detect login state, prioritizing stealth over reliability:
@@ -249,8 +261,12 @@ The bot uses a layered approach to detect login state, prioritizing stealth over
 
 **Optional diagnostics:**
 
-- Enable `login_detection_capture` to capture screenshots and HTML dumps when state is `UNKNOWN`
-- Enable `pause_on_login_detection_failure` to pause the bot for manual inspection (interactive sessions only; requires `login_detection_capture=true`)
+- Enable `capture_on.login_detection` to capture screenshots and HTML dumps when state is `UNKNOWN`
+- Enable `capture_on.publish` to capture screenshots, HTML dumps, and JSON payloads for each failed publish attempt (e.g., attempts 1–3).
+- Enable `capture_log_copy` to copy the entire bot log file when a diagnostic event triggers (e.g., `capture_on.publish` or `capture_on.login_detection`):
+  - If multiple diagnostics trigger in the same run, the log will be copied multiple times
+  - Review or redact artifacts before sharing publicly
+- Enable `pause_on_login_detection_failure` to pause the bot for manual inspection in interactive sessions. This requires `capture_on.login_detection=true`; if this is not enabled, the runtime will fail startup with a validation error.
 - Use custom `output_dir` to specify where artifacts are saved
 
 **Output locations (default):**
@@ -259,7 +275,7 @@ The bot uses a layered approach to detect login state, prioritizing stealth over
 - **System-wide mode (XDG)**: `~/.cache/kleinanzeigen-bot/diagnostics/` (Linux) or `~/Library/Caches/kleinanzeigen-bot/diagnostics/` (macOS)
 - **Custom**: Path resolved relative to your `config.yaml` if `output_dir` is specified
 
-> **⚠️ PII Warning:** HTML dumps may contain your account email or other personally identifiable information. Review files in the diagnostics output directory before sharing them publicly.
+> **⚠️ PII Warning:** HTML dumps, JSON payloads, and log copies may contain PII. Typical examples include account email, ad titles/descriptions, contact info, and prices. Log copies are produced by `capture_log_copy` when diagnostics capture runs, such as `capture_on.publish` or `capture_on.login_detection`. Review or redact these artifacts before sharing them publicly.
 
 ## Installation Modes
 
diff --git a/schemas/config.schema.json b/schemas/config.schema.json
index 573dda4..13aeac0 100644
--- a/schemas/config.schema.json
+++ b/schemas/config.schema.json
@@ -263,6 +263,25 @@
       "title": "CaptchaConfig",
       "type": "object"
     },
+    "CaptureOnConfig": {
+      "description": "Configuration for which operations should trigger diagnostics capture.",
+      "properties": {
+        "login_detection": {
+          "default": false,
+          "description": "Capture screenshot and HTML when login state detection fails",
+          "title": "Login Detection",
+          "type": "boolean"
+        },
+        "publish": {
+          "default": false,
+          "description": "Capture screenshot, HTML, and JSON on publish failures",
+          "title": "Publish",
+          "type": "boolean"
+        }
+      },
+      "title": "CaptureOnConfig",
+      "type": "object"
+    },
     "ContactDefaults": {
       "properties": {
         "name": {
@@ -369,15 +388,19 @@
     },
     "DiagnosticsConfig": {
       "properties": {
-        "login_detection_capture": {
+        "capture_on": {
+          "$ref": "#/$defs/CaptureOnConfig",
+          "description": "Enable diagnostics capture for specific operations."
+        },
+        "capture_log_copy": {
           "default": false,
-          "description": "If true, capture diagnostics artifacts (screenshot + HTML) when login detection returns UNKNOWN.",
-          "title": "Login Detection Capture",
+          "description": "If true, copy the entire bot log file when diagnostics are captured (may duplicate log content).",
+          "title": "Capture Log Copy",
           "type": "boolean"
         },
         "pause_on_login_detection_failure": {
           "default": false,
-          "description": "If true, pause (interactive runs only) after capturing login detection diagnostics so that user can inspect the browser. Requires login_detection_capture to be enabled.",
+          "description": "If true, pause (interactive runs only) after capturing login detection diagnostics so that user can inspect the browser. Requires capture_on.login_detection to be enabled.",
           "title": "Pause On Login Detection Failure",
           "type": "boolean"
         },
@@ -520,7 +543,7 @@
         },
         "email_verification": {
           "default": 4.0,
-          "description": "Timeout for eMail verification prompts.",
+          "description": "Timeout for email verification prompts.",
           "minimum": 0.1,
           "title": "Email Verification",
           "type": "number"
diff --git a/src/kleinanzeigen_bot/__init__.py b/src/kleinanzeigen_bot/__init__.py
index bc3044d..89df8bf 100644
--- a/src/kleinanzeigen_bot/__init__.py
+++ b/src/kleinanzeigen_bot/__init__.py
@@ -1,7 +1,7 @@
 # SPDX-FileCopyrightText: © Sebastian Thomschke and contributors
 # SPDX-License-Identifier: AGPL-3.0-or-later
 # SPDX-ArtifactOfProjectHomePage: https://github.com/Second-Hand-Friends/kleinanzeigen-bot/
-import atexit, asyncio, enum, json, os, re, secrets, signal, sys, textwrap  # isort: skip
+import atexit, asyncio, enum, json, os, re, signal, sys, textwrap  # isort: skip
 import getopt  # pylint: disable=deprecated-module
 import urllib.parse as urllib_parse
 from datetime import datetime
@@ -19,7 +19,7 @@ from ._version import __version__
 from .model.ad_model import MAX_DESCRIPTION_LENGTH, Ad, AdPartial, Contact, calculate_auto_price
 from .model.config_model import Config
 from .update_checker import UpdateChecker
-from .utils import dicts, error_handlers, loggers, misc, xdg_paths
+from .utils import diagnostics, dicts, error_handlers, loggers, misc, xdg_paths
 from .utils.exceptions import CaptchaEncountered
 from .utils.files import abspath
 from .utils.i18n import Locale, get_current_locale, pluralize, set_current_locale
@@ -31,6 +31,8 @@ from .utils.web_scraping_mixin import By, Element, Is, WebScrapingMixin
 LOG:Final[loggers.Logger] = loggers.get_logger(__name__)
 LOG.setLevel(loggers.INFO)
 
+PUBLISH_MAX_RETRIES:Final[int] = 3
+
 colorama.just_fix_windows_console()
 
 
@@ -961,8 +963,8 @@ class KleinanzeigenBot(WebScrapingMixin):  # noqa: PLR0904
         return (Path.cwd() / ".temp" / "diagnostics").resolve()
 
     async def _capture_login_detection_diagnostics_if_enabled(self) -> None:
-        diagnostics = getattr(self.config, "diagnostics", None)
-        if diagnostics is None or not diagnostics.login_detection_capture:
+        cfg = getattr(self.config, "diagnostics", None)
+        if cfg is None or not cfg.capture_on.login_detection:
             return
 
         if self._login_detection_diagnostics_captured:
@@ -975,35 +977,79 @@ class KleinanzeigenBot(WebScrapingMixin):  # noqa: PLR0904
         self._login_detection_diagnostics_captured = True
 
         try:
-            out_dir = self._diagnostics_output_dir()
-            out_dir.mkdir(parents = True, exist_ok = True)
-
-            # Intentionally no username/PII in filename.
-            ts = misc.now().strftime("%Y%m%dT%H%M%S")
-            suffix = secrets.token_hex(4)
-            base = f"login_detection_unknown_{ts}_{suffix}"
-            screenshot_path = out_dir / f"{base}.png"
-            html_path = out_dir / f"{base}.html"
-
-            try:
-                await page.save_screenshot(str(screenshot_path))
-            except Exception as exc:  # noqa: BLE001
-                LOG.debug("Login diagnostics screenshot capture failed: %s", exc)
-
-            try:
-                html = await page.get_content()
-                html_path.write_text(html, encoding = "utf-8")
-            except Exception as exc:  # noqa: BLE001
-                LOG.debug("Login diagnostics HTML capture failed: %s", exc)
+            await diagnostics.capture_diagnostics(
+                output_dir = self._diagnostics_output_dir(),
+                base_prefix = "login_detection_unknown",
+                page = page,
+            )
         except Exception as exc:  # noqa: BLE001
-            LOG.debug("Login diagnostics capture failed: %s", exc)
+            LOG.debug(
+                "Login diagnostics capture failed (output_dir=%s, base_prefix=%s): %s",
+                self._diagnostics_output_dir(),
+                "login_detection_unknown",
+                exc,
+            )
 
-        if getattr(diagnostics, "pause_on_login_detection_failure", False) and getattr(sys.stdin, "isatty", lambda: False)():
+        if cfg.pause_on_login_detection_failure and getattr(sys.stdin, "isatty", lambda: False)():
             LOG.warning("############################################")
             LOG.warning("# Login detection returned UNKNOWN. Browser is paused for manual inspection.")
             LOG.warning("############################################")
             await ainput(_("Press a key to continue..."))
 
+    async def _capture_publish_error_diagnostics_if_enabled(
+        self,
+        ad_cfg:Ad,
+        ad_cfg_orig:dict[str, Any],
+        ad_file:str,
+        attempt:int,
+        exc:Exception,
+    ) -> None:
+        """Capture publish failure diagnostics when enabled and a page is available.
+
+        Runs only if cfg.capture_on.publish is enabled and self.page is set.
+        Uses the ad configuration and publish attempt details to write screenshot, HTML,
+        JSON payload, and optional log copy for debugging.
+        """
+        cfg = getattr(self.config, "diagnostics", None)
+        if cfg is None or not cfg.capture_on.publish:
+            return
+
+        page = getattr(self, "page", None)
+        if page is None:
+            return
+
+        # Use the ad filename (without extension) as identifier
+        ad_file_stem = Path(ad_file).stem
+
+        json_payload = {
+            "timestamp": misc.now().isoformat(timespec = "seconds"),
+            "attempt": attempt,
+            "page_url": getattr(page, "url", None),
+            "exception": {
+                "type": exc.__class__.__name__,
+                "message": str(exc),
+                "repr": repr(exc),
+            },
+            "ad_file": ad_file,
+            "ad_title": ad_cfg.title,
+            "ad_config_effective": ad_cfg.model_dump(mode = "json"),
+            "ad_config_original": ad_cfg_orig,
+        }
+
+        try:
+            await diagnostics.capture_diagnostics(
+                output_dir = self._diagnostics_output_dir(),
+                base_prefix = "publish_error",
+                attempt = attempt,
+                subject = ad_file_stem,
+                page = page,
+                json_payload = json_payload,
+                log_file_path = self.log_file_path,
+                copy_log = cfg.capture_log_copy,
+            )
+        except Exception as error:  # noqa: BLE001
+            LOG.warning("Diagnostics capture failed during publish error handling: %s", error)
+
     async def is_logged_in(self, *, include_probe:bool = True) -> bool:
         # Use login_detection timeout (10s default) instead of default (5s)
         # to allow sufficient time for client-side JavaScript rendering after page load.
@@ -1298,7 +1344,7 @@ class KleinanzeigenBot(WebScrapingMixin):  # noqa: PLR0904
     async def publish_ads(self, ad_cfgs:list[tuple[str, Ad, dict[str, Any]]]) -> None:
         count = 0
         failed_count = 0
-        max_retries = 3
+        max_retries = PUBLISH_MAX_RETRIES
 
         published_ads = await self._fetch_published_ads()
 
@@ -1321,6 +1367,7 @@ class KleinanzeigenBot(WebScrapingMixin):  # noqa: PLR0904
                 except asyncio.CancelledError:
                     raise  # Respect task cancellation
                 except (TimeoutError, ProtocolException) as ex:
+                    await self._capture_publish_error_diagnostics_if_enabled(ad_cfg, ad_cfg_orig, ad_file, attempt, ex)
                     if attempt < max_retries:
                         LOG.warning("Attempt %s/%s failed for '%s': %s. Retrying...", attempt, max_retries, ad_cfg.title, ex)
                         await self.web_sleep(2)  # Wait before retry
diff --git a/src/kleinanzeigen_bot/model/config_model.py b/src/kleinanzeigen_bot/model/config_model.py
index 1881842..1d538fd 100644
--- a/src/kleinanzeigen_bot/model/config_model.py
+++ b/src/kleinanzeigen_bot/model/config_model.py
@@ -11,10 +11,12 @@ from pydantic import AfterValidator, Field, model_validator
 from typing_extensions import deprecated
 
 from kleinanzeigen_bot.model.update_check_model import UpdateCheckConfig
-from kleinanzeigen_bot.utils import dicts
+from kleinanzeigen_bot.utils import dicts, loggers
 from kleinanzeigen_bot.utils.misc import get_attr
 from kleinanzeigen_bot.utils.pydantics import ContextualModel
 
+LOG:Final[loggers.Logger] = loggers.get_logger(__name__)
+
 _MAX_PERCENTAGE:Final[int] = 100
 
 
@@ -195,25 +197,73 @@ class TimeoutConfig(ContextualModel):
         return base * self.multiplier * backoff
 
 
-class DiagnosticsConfig(ContextualModel):
-    login_detection_capture:bool = Field(
+class CaptureOnConfig(ContextualModel):
+    """Configuration for which operations should trigger diagnostics capture."""
+
+    login_detection:bool = Field(
         default = False,
-        description = "If true, capture diagnostics artifacts (screenshot + HTML) when login detection returns UNKNOWN.",
+        description = "Capture screenshot and HTML when login state detection fails",
+    )
+    publish:bool = Field(
+        default = False,
+        description = "Capture screenshot, HTML, and JSON on publish failures",
+    )
+
+
+class DiagnosticsConfig(ContextualModel):
+    capture_on:CaptureOnConfig = Field(
+        default_factory = CaptureOnConfig,
+        description = "Enable diagnostics capture for specific operations.",
+    )
+    capture_log_copy:bool = Field(
+        default = False,
+        description = "If true, copy the entire bot log file when diagnostics are captured (may duplicate log content).",
     )
     pause_on_login_detection_failure:bool = Field(
         default = False,
         description = "If true, pause (interactive runs only) after capturing login detection diagnostics "
-        "so that user can inspect the browser. Requires login_detection_capture to be enabled.",
+        "so that user can inspect the browser. Requires capture_on.login_detection to be enabled.",
     )
     output_dir:str | None = Field(
         default = None,
         description = "Optional output directory for diagnostics artifacts. If omitted, a safe default is used based on installation mode.",
     )
 
+    @model_validator(mode = "before")
+    @classmethod
+    def migrate_legacy_diagnostics_keys(cls, data:dict[str, Any]) -> dict[str, Any]:
+        """Migrate legacy login_detection_capture and publish_error_capture keys."""
+
+        # Migrate legacy login_detection_capture -> capture_on.login_detection
+        # Only migrate if the new key is not already explicitly set
+        if "login_detection_capture" in data:
+            LOG.warning("Deprecated: 'login_detection_capture' is replaced by 'capture_on.login_detection'. Please update your config.")
+            if "capture_on" not in data or data["capture_on"] is None:
+                data["capture_on"] = {}
+            if isinstance(data["capture_on"], dict) and "login_detection" not in data["capture_on"]:
+                data["capture_on"]["login_detection"] = data.pop("login_detection_capture")
+            else:
+                # Remove legacy key but don't overwrite explicit new value
+                data.pop("login_detection_capture")
+
+        # Migrate legacy publish_error_capture -> capture_on.publish
+        # Only migrate if the new key is not already explicitly set
+        if "publish_error_capture" in data:
+            LOG.warning("Deprecated: 'publish_error_capture' is replaced by 'capture_on.publish'. Please update your config.")
+            if "capture_on" not in data or data["capture_on"] is None:
+                data["capture_on"] = {}
+            if isinstance(data["capture_on"], dict) and "publish" not in data["capture_on"]:
+                data["capture_on"]["publish"] = data.pop("publish_error_capture")
+            else:
+                # Remove legacy key but don't overwrite explicit new value
+                data.pop("publish_error_capture")
+
+        return data
+
     @model_validator(mode = "after")
     def _validate_pause_requires_capture(self) -> "DiagnosticsConfig":
-        if self.pause_on_login_detection_failure and not self.login_detection_capture:
-            raise ValueError(_("pause_on_login_detection_failure requires login_detection_capture to be enabled"))
+        if self.pause_on_login_detection_failure and not self.capture_on.login_detection:
+            raise ValueError(_("pause_on_login_detection_failure requires capture_on.login_detection to be enabled"))
         return self
 
 
diff --git a/src/kleinanzeigen_bot/resources/translations.de.yaml b/src/kleinanzeigen_bot/resources/translations.de.yaml
index 1f155b6..9189e81 100644
--- a/src/kleinanzeigen_bot/resources/translations.de.yaml
+++ b/src/kleinanzeigen_bot/resources/translations.de.yaml
@@ -75,6 +75,9 @@ kleinanzeigen_bot/__init__.py:
     "# Login detection returned UNKNOWN. Browser is paused for manual inspection.": "# Login-Erkennung ergab UNKNOWN. Browser ist zur manuellen Prüfung angehalten."
     "Press a key to continue...": "Eine Taste drücken, um fortzufahren..."
 
+  _capture_publish_error_diagnostics_if_enabled:
+    "Diagnostics capture failed during publish error handling: %s": "Diagnose-Erfassung fehlgeschlagen während der Veröffentlichung-Fehlerbehandlung: %s"
+
   login:
     "Checking if already logged in...": "Überprüfe, ob bereits eingeloggt..."
     "Current page URL after opening homepage: %s": "Aktuelle Seiten-URL nach dem Öffnen der Startseite: %s"
@@ -619,10 +622,13 @@ kleinanzeigen_bot/model/config_model.py:
     "amount must be specified when auto_price_reduction is enabled": "amount muss angegeben werden, wenn auto_price_reduction aktiviert ist"
     "min_price must be specified when auto_price_reduction is enabled": "min_price muss angegeben werden, wenn auto_price_reduction aktiviert ist"
     "Percentage reduction amount must not exceed %s": "Prozentuale Reduktionsmenge darf %s nicht überschreiten"
+  migrate_legacy_diagnostics_keys:
+    "Deprecated: 'login_detection_capture' is replaced by 'capture_on.login_detection'. Please update your config.": "Veraltet: 'login_detection_capture' wurde durch 'capture_on.login_detection' ersetzt. Bitte aktualisieren Sie Ihre Konfiguration."
+    "Deprecated: 'publish_error_capture' is replaced by 'capture_on.publish'. Please update your config.": "Veraltet: 'publish_error_capture' wurde durch 'capture_on.publish' ersetzt. Bitte aktualisieren Sie Ihre Konfiguration."
   _validate_glob_pattern:
     "must be a non-empty, non-blank glob pattern": "muss ein nicht-leeres Glob-Muster sein"
   _validate_pause_requires_capture:
-    "pause_on_login_detection_failure requires login_detection_capture to be enabled": "pause_on_login_detection_failure erfordert, dass login_detection_capture aktiviert ist"
+    "pause_on_login_detection_failure requires capture_on.login_detection to be enabled": "pause_on_login_detection_failure erfordert, dass capture_on.login_detection aktiviert ist"
 
 #################################################
 kleinanzeigen_bot/model/ad_model.py:
@@ -656,6 +662,21 @@ kleinanzeigen_bot/model/update_check_state.py:
     "Invalid interval format or unsupported unit: %s. Using default interval for this run.": "Ungültiges Intervallformat oder nicht unterstützte Einheit: %s. Es wird das Standardintervall für diesen Durchlauf verwendet."
     "Negative interval: %s. Minimum interval is 1d. Using default interval for this run.": "Negatives Intervall: %s. Das Mindestintervall beträgt 1 Tag. Es wird das Standardintervall für diesen Durchlauf verwendet."
 
+#################################################
+kleinanzeigen_bot/utils/diagnostics.py:
+#################################################
+  _copy_log_sync:
+    "Log file not found for diagnostics copy: %s": "Logdatei nicht gefunden für Diagnosekopie: %s"
+
+  capture_diagnostics:
+    "Diagnostics screenshot capture failed: %s": "Diagnose-Screenshot-Erfassung fehlgeschlagen: %s"
+    "Diagnostics HTML capture failed: %s": "Diagnose-HTML-Erfassung fehlgeschlagen: %s"
+    "Diagnostics JSON capture failed: %s": "Diagnose-JSON-Erfassung fehlgeschlagen: %s"
+    "Diagnostics log copy failed: %s": "Diagnose-Log-Kopie fehlgeschlagen: %s"
+    "Diagnostics saved: %s": "Diagnosedaten gespeichert: %s"
+    "Diagnostics capture attempted but no artifacts were saved (all captures failed)": "Diagnoseerfassung versucht, aber keine Artefakte gespeichert (alle Erfassungen fehlgeschlagen)"
+    "Diagnostics capture failed: %s": "Diagnoseerfassung fehlgeschlagen: %s"
+
 #################################################
 kleinanzeigen_bot/utils/xdg_paths.py:
 #################################################
diff --git a/src/kleinanzeigen_bot/utils/diagnostics.py b/src/kleinanzeigen_bot/utils/diagnostics.py
new file mode 100644
index 0000000..eb28e3d
--- /dev/null
+++ b/src/kleinanzeigen_bot/utils/diagnostics.py
@@ -0,0 +1,135 @@
+# SPDX-FileCopyrightText: © Jens Bergmann and contributors
+# SPDX-License-Identifier: AGPL-3.0-or-later
+# SPDX-ArtifactOfProjectHomePage: https://github.com/Second-Hand-Friends/kleinanzeigen-bot/
+import asyncio, json, re, secrets, shutil  # isort: skip
+from pathlib import Path
+from typing import Any, Final
+
+from kleinanzeigen_bot.utils import loggers, misc
+
+LOG:Final[loggers.Logger] = loggers.get_logger(__name__)
+
+
+class CaptureResult:
+    """Result of a diagnostics capture attempt."""
+
+    def __init__(self) -> None:
+        self.saved_artifacts:list[Path] = []
+
+    def add_saved(self, path:Path) -> None:
+        """Add a successfully saved artifact."""
+        self.saved_artifacts.append(path)
+
+    def has_any(self) -> bool:
+        """Check if any artifacts were saved."""
+        return bool(self.saved_artifacts)
+
+
+def _write_json_sync(json_path:Path, json_payload:dict[str, Any]) -> None:
+    """Synchronous helper to write JSON to file."""
+    with json_path.open("w", encoding = "utf-8") as handle:
+        json.dump(json_payload, handle, indent = 2, default = str)
+        handle.write("\n")
+
+
+def _copy_log_sync(log_file_path:str, log_path:Path) -> bool:
+    """Synchronous helper to copy log file. Returns True if copy succeeded."""
+    log_source = Path(log_file_path)
+    if not log_source.exists():
+        LOG.warning("Log file not found for diagnostics copy: %s", log_file_path)
+        return False
+    loggers.flush_all_handlers()
+    shutil.copy2(log_source, log_path)
+    return True
+
+
+async def capture_diagnostics(
+    *,
+    output_dir:Path,
+    base_prefix:str,
+    attempt:int | None = None,
+    subject:str | None = None,
+    page:Any | None = None,
+    json_payload:dict[str, Any] | None = None,
+    log_file_path:str | None = None,
+    copy_log:bool = False,
+) -> CaptureResult:
+    """Capture diagnostics artifacts for a given operation.
+
+    Args:
+        output_dir: The output directory for diagnostics artifacts
+        base_prefix: Base filename prefix (e.g., 'login_detection_unknown', 'publish_error')
+        attempt: Optional attempt number for retry operations
+        subject: Optional subject identifier (e.g., ad token)
+        page: Optional page object with save_screenshot and get_content methods
+        json_payload: Optional JSON data to save
+        log_file_path: Optional log file path to copy
+        copy_log: Whether to copy log file
+
+    Returns:
+        CaptureResult containing the list of successfully saved artifacts
+    """
+    result = CaptureResult()
+
+    try:
+        await asyncio.to_thread(output_dir.mkdir, parents = True, exist_ok = True)
+
+        ts = misc.now().strftime("%Y%m%dT%H%M%S")
+        suffix = secrets.token_hex(4)
+        base = f"{base_prefix}_{ts}_{suffix}"
+
+        if attempt is not None:
+            base = f"{base}_attempt{attempt}"
+
+        if subject:
+            safe_subject = re.sub(r"[^A-Za-z0-9_-]", "_", subject)
+            base = f"{base}_{safe_subject}"
+
+        screenshot_path = output_dir / f"{base}.png"
+        html_path = output_dir / f"{base}.html"
+        json_path = output_dir / f"{base}.json"
+        log_path = output_dir / f"{base}.log"
+
+        if page:
+            try:
+                await page.save_screenshot(str(screenshot_path))
+                result.add_saved(screenshot_path)
+            except Exception as exc:  # noqa: BLE001
+                LOG.debug("Diagnostics screenshot capture failed: %s", exc)
+
+            try:
+                html = await page.get_content()
+                await asyncio.to_thread(html_path.write_text, html, encoding = "utf-8")
+                result.add_saved(html_path)
+            except Exception as exc:  # noqa: BLE001
+                LOG.debug("Diagnostics HTML capture failed: %s", exc)
+
+        if json_payload is not None:
+            try:
+                await asyncio.to_thread(_write_json_sync, json_path, json_payload)
+                result.add_saved(json_path)
+            except Exception as exc:  # noqa: BLE001
+                LOG.debug("Diagnostics JSON capture failed: %s", exc)
+
+        if copy_log and log_file_path:
+            try:
+                copy_succeeded = await asyncio.to_thread(_copy_log_sync, log_file_path, log_path)
+                if copy_succeeded:
+                    result.add_saved(log_path)
+            except Exception as exc:  # noqa: BLE001
+                LOG.debug("Diagnostics log copy failed: %s", exc)
+
+        # Determine if any capture was actually requested
+        capture_requested = page is not None or json_payload is not None or (copy_log and log_file_path)
+
+        if result.has_any():
+            artifacts_str = " ".join(map(str, result.saved_artifacts))
+            LOG.info("Diagnostics saved: %s", artifacts_str)
+        elif capture_requested:
+            LOG.warning("Diagnostics capture attempted but no artifacts were saved (all captures failed)")
+        else:
+            LOG.debug("No diagnostics capture requested")
+    except Exception as exc:  # noqa: BLE001
+        LOG.debug("Diagnostics capture failed: %s", exc)
+
+    return result
diff --git a/tests/unit/test_config_model.py b/tests/unit/test_config_model.py
index f4fa6dc..6b644da 100644
--- a/tests/unit/test_config_model.py
+++ b/tests/unit/test_config_model.py
@@ -87,7 +87,7 @@ def test_timeout_config_resolve_falls_back_to_default() -> None:
 def test_diagnostics_pause_requires_capture_validation() -> None:
     """
     Unit: DiagnosticsConfig validator ensures pause_on_login_detection_failure
-    requires login_detection_capture to be enabled.
+    requires capture_on.login_detection to be enabled.
     """
     minimal_cfg = {
         "ad_defaults": {"contact": {"name": "dummy", "zipcode": "12345"}},
@@ -95,12 +95,98 @@ def test_diagnostics_pause_requires_capture_validation() -> None:
         "publishing": {"delete_old_ads": "BEFORE_PUBLISH", "delete_old_ads_by_title": False},
     }
 
-    valid_cfg = {**minimal_cfg, "diagnostics": {"login_detection_capture": True, "pause_on_login_detection_failure": True}}
+    valid_cfg = {**minimal_cfg, "diagnostics": {"capture_on": {"login_detection": True}, "pause_on_login_detection_failure": True}}
     config = Config.model_validate(valid_cfg)
     assert config.diagnostics is not None
     assert config.diagnostics.pause_on_login_detection_failure is True
-    assert config.diagnostics.login_detection_capture is True
+    assert config.diagnostics.capture_on.login_detection is True
 
-    invalid_cfg = {**minimal_cfg, "diagnostics": {"login_detection_capture": False, "pause_on_login_detection_failure": True}}
-    with pytest.raises(ValueError, match = "pause_on_login_detection_failure requires login_detection_capture to be enabled"):
+    invalid_cfg = {**minimal_cfg, "diagnostics": {"capture_on": {"login_detection": False}, "pause_on_login_detection_failure": True}}
+    with pytest.raises(ValueError, match = "pause_on_login_detection_failure requires capture_on.login_detection to be enabled"):
         Config.model_validate(invalid_cfg)
+
+
+def test_diagnostics_legacy_login_detection_capture_migration_when_capture_on_exists() -> None:
+    """
+    Unit: Test that legacy login_detection_capture is removed but doesn't overwrite explicit capture_on.login_detection.
+    """
+    minimal_cfg = {
+        "ad_defaults": {"contact": {"name": "dummy", "zipcode": "12345"}},
+        "login": {"username": "dummy", "password": "dummy"},  # noqa: S105
+    }
+
+    # When capture_on.login_detection is explicitly set to False, legacy True should be ignored
+    cfg_with_explicit = {
+        **minimal_cfg,
+        "diagnostics": {
+            "login_detection_capture": True,  # legacy key
+            "capture_on": {"login_detection": False},  # explicit new key set to False
+        },
+    }
+    config = Config.model_validate(cfg_with_explicit)
+    assert config.diagnostics is not None
+    assert config.diagnostics.capture_on.login_detection is False  # explicit value preserved
+
+
+def test_diagnostics_legacy_publish_error_capture_migration_when_capture_on_exists() -> None:
+    """
+    Unit: Test that legacy publish_error_capture is removed but doesn't overwrite explicit capture_on.publish.
+    """
+    minimal_cfg = {
+        "ad_defaults": {"contact": {"name": "dummy", "zipcode": "12345"}},
+        "login": {"username": "dummy", "password": "dummy"},  # noqa: S105
+    }
+
+    # When capture_on.publish is explicitly set to False, legacy True should be ignored
+    cfg_with_explicit = {
+        **minimal_cfg,
+        "diagnostics": {
+            "publish_error_capture": True,  # legacy key
+            "capture_on": {"publish": False},  # explicit new key set to False
+        },
+    }
+    config = Config.model_validate(cfg_with_explicit)
+    assert config.diagnostics is not None
+    assert config.diagnostics.capture_on.publish is False  # explicit value preserved
+
+
+def test_diagnostics_legacy_login_detection_capture_migration_when_capture_on_is_none() -> None:
+    """
+    Unit: Test that legacy login_detection_capture is migrated when capture_on is None.
+    """
+    minimal_cfg = {
+        "ad_defaults": {"contact": {"name": "dummy", "zipcode": "12345"}},
+        "login": {"username": "dummy", "password": "dummy"},  # noqa: S105
+    }
+
+    cfg_with_null_capture_on = {
+        **minimal_cfg,
+        "diagnostics": {
+            "login_detection_capture": True,  # legacy key
+            "capture_on": None,  # capture_on is explicitly None
+        },
+    }
+    config = Config.model_validate(cfg_with_null_capture_on)
+    assert config.diagnostics is not None
+    assert config.diagnostics.capture_on.login_detection is True  # legacy value migrated
+
+
+def test_diagnostics_legacy_publish_error_capture_migration_when_capture_on_is_none() -> None:
+    """
+    Unit: Test that legacy publish_error_capture is migrated when capture_on is None.
+    """
+    minimal_cfg = {
+        "ad_defaults": {"contact": {"name": "dummy", "zipcode": "12345"}},
+        "login": {"username": "dummy", "password": "dummy"},  # noqa: S105
+    }
+
+    cfg_with_null_capture_on = {
+        **minimal_cfg,
+        "diagnostics": {
+            "publish_error_capture": True,  # legacy key
+            "capture_on": None,  # capture_on is explicitly None
+        },
+    }
+    config = Config.model_validate(cfg_with_null_capture_on)
+    assert config.diagnostics is not None
+    assert config.diagnostics.capture_on.publish is True  # legacy value migrated
diff --git a/tests/unit/test_diagnostics.py b/tests/unit/test_diagnostics.py
new file mode 100644
index 0000000..0774d3c
--- /dev/null
+++ b/tests/unit/test_diagnostics.py
@@ -0,0 +1,224 @@
+# SPDX-FileCopyrightText: © 2025 Sebastian Thomschke and contributors
+# SPDX-License-Identifier: AGPL-3.0-or-later
+# SPDX-ArtifactOfProjectHomePage: https://github.com/Second-Hand-Friends/kleinanzeigen-bot/
+from pathlib import Path
+from unittest.mock import AsyncMock, MagicMock
+
+import pytest
+
+from kleinanzeigen_bot.utils import diagnostics as diagnostics_module
+from kleinanzeigen_bot.utils.diagnostics import capture_diagnostics
+
+
+@pytest.mark.unit
+class TestDiagnosticsCapture:
+    """Tests for diagnostics capture functionality."""
+
+    @pytest.mark.asyncio
+    async def test_capture_diagnostics_creates_output_dir(self, tmp_path:Path) -> None:
+        """Test that capture_diagnostics creates output directory."""
+        mock_page = AsyncMock()
+
+        output_dir = tmp_path / "diagnostics"
+        _ = await capture_diagnostics(
+            output_dir = output_dir,
+            base_prefix = "test",
+            page = mock_page,
+        )
+
+        # Verify directory was created
+        assert output_dir.exists()
+
+    @pytest.mark.asyncio
+    async def test_capture_diagnostics_creates_screenshot(self, tmp_path:Path) -> None:
+        """Test that capture_diagnostics creates screenshot file."""
+        mock_page = AsyncMock()
+        mock_page.save_screenshot = AsyncMock()
+
+        output_dir = tmp_path / "diagnostics"
+        result = await capture_diagnostics(
+            output_dir = output_dir,
+            base_prefix = "test",
+            page = mock_page,
+        )
+
+        # Verify screenshot file was created and page method was called
+        assert len(result.saved_artifacts) == 1
+        assert result.saved_artifacts[0].suffix == ".png"
+        mock_page.save_screenshot.assert_awaited_once()
+
+    @pytest.mark.asyncio
+    async def test_capture_diagnostics_creates_html(self, tmp_path:Path) -> None:
+        """Test that capture_diagnostics creates HTML file."""
+        mock_page = AsyncMock()
+        mock_page.get_content = AsyncMock(return_value = "<html></html>")
+
+        output_dir = tmp_path / "diagnostics"
+        result = await capture_diagnostics(
+            output_dir = output_dir,
+            base_prefix = "test",
+            page = mock_page,
+        )
+
+        # Verify HTML file was created along with screenshot
+        assert len(result.saved_artifacts) == 2
+        assert any(a.suffix == ".html" for a in result.saved_artifacts)
+
+    @pytest.mark.asyncio
+    async def test_capture_diagnostics_creates_json(self, tmp_path:Path) -> None:
+        """Test that capture_diagnostics creates JSON file."""
+        mock_page = AsyncMock()
+        mock_page.get_content = AsyncMock(return_value = "<html></html>")
+
+        output_dir = tmp_path / "diagnostics"
+        result = await capture_diagnostics(
+            output_dir = output_dir,
+            base_prefix = "test",
+            page = mock_page,
+            json_payload = {"test": "data"},
+        )
+
+        # Verify JSON file was created along with HTML and screenshot
+        assert len(result.saved_artifacts) == 3
+        assert any(a.suffix == ".json" for a in result.saved_artifacts)
+
+    @pytest.mark.asyncio
+    async def test_capture_diagnostics_copies_log_file(self, tmp_path:Path) -> None:
+        """Test that capture_diagnostics copies log file when enabled."""
+        log_file = tmp_path / "test.log"
+        log_file.write_text("test log content")
+
+        output_dir = tmp_path / "diagnostics"
+        result = await capture_diagnostics(
+            output_dir = output_dir,
+            base_prefix = "test",
+            page = None,  # No page to avoid screenshot
+            log_file_path = str(log_file),
+            copy_log = True,
+        )
+
+        # Verify log was copied
+        assert len(result.saved_artifacts) == 1
+        assert result.saved_artifacts[0].suffix == ".log"
+
+    def test_copy_log_sync_returns_false_when_file_not_found(self, tmp_path:Path) -> None:
+        """Test _copy_log_sync returns False when log file does not exist."""
+        non_existent_log = tmp_path / "non_existent.log"
+        log_path = tmp_path / "output.log"
+
+        result = diagnostics_module._copy_log_sync(str(non_existent_log), log_path)
+
+        assert result is False
+        assert not log_path.exists()
+
+    @pytest.mark.asyncio
+    async def test_capture_diagnostics_handles_screenshot_exception(self, tmp_path:Path, caplog:pytest.LogCaptureFixture) -> None:
+        """Test that capture_diagnostics handles screenshot capture exceptions gracefully."""
+        mock_page = AsyncMock()
+        mock_page.save_screenshot = AsyncMock(side_effect = Exception("Screenshot failed"))
+
+        output_dir = tmp_path / "diagnostics"
+        result = await capture_diagnostics(
+            output_dir = output_dir,
+            base_prefix = "test",
+            page = mock_page,
+        )
+
+        # Verify no artifacts were saved due to exception
+        assert len(result.saved_artifacts) == 0
+        assert "Diagnostics screenshot capture failed" in caplog.text
+
+    @pytest.mark.asyncio
+    async def test_capture_diagnostics_handles_json_exception(self, tmp_path:Path, caplog:pytest.LogCaptureFixture, monkeypatch:pytest.MonkeyPatch) -> None:
+        """Test that capture_diagnostics handles JSON write exceptions gracefully."""
+        mock_page = AsyncMock()
+        mock_page.get_content = AsyncMock(return_value = "<html></html>")
+
+        output_dir = tmp_path / "diagnostics"
+
+        # Mock _write_json_sync to raise an exception
+        monkeypatch.setattr(diagnostics_module, "_write_json_sync", MagicMock(side_effect = Exception("JSON write failed")))
+
+        result = await capture_diagnostics(
+            output_dir = output_dir,
+            base_prefix = "test",
+            page = mock_page,
+            json_payload = {"test": "data"},
+        )
+
+        # Verify screenshot and HTML were saved, but JSON failed
+        assert len(result.saved_artifacts) == 2
+        assert any(a.suffix == ".png" for a in result.saved_artifacts)
+        assert any(a.suffix == ".html" for a in result.saved_artifacts)
+        assert not any(a.suffix == ".json" for a in result.saved_artifacts)
+        assert "Diagnostics JSON capture failed" in caplog.text
+
+    @pytest.mark.asyncio
+    async def test_capture_diagnostics_handles_log_copy_exception(
+        self, tmp_path:Path, caplog:pytest.LogCaptureFixture, monkeypatch:pytest.MonkeyPatch
+    ) -> None:
+        """Test that capture_diagnostics handles log copy exceptions gracefully."""
+        # Create a log file
+        log_file = tmp_path / "test.log"
+        log_file.write_text("test log content")
+
+        output_dir = tmp_path / "diagnostics"
+
+        # Mock _copy_log_sync to raise an exception
+        original_copy_log = diagnostics_module._copy_log_sync
+        monkeypatch.setattr(diagnostics_module, "_copy_log_sync", MagicMock(side_effect = Exception("Copy failed")))
+
+        try:
+            result = await capture_diagnostics(
+                output_dir = output_dir,
+                base_prefix = "test",
+                page = None,
+                log_file_path = str(log_file),
+                copy_log = True,
+            )
+
+            # Verify no artifacts were saved due to exception
+            assert len(result.saved_artifacts) == 0
+            assert "Diagnostics log copy failed" in caplog.text
+        finally:
+            monkeypatch.setattr(diagnostics_module, "_copy_log_sync", original_copy_log)
+
+    @pytest.mark.asyncio
+    async def test_capture_diagnostics_logs_warning_when_all_captures_fail(
+        self, tmp_path:Path, caplog:pytest.LogCaptureFixture, monkeypatch:pytest.MonkeyPatch
+    ) -> None:
+        """Test warning is logged when capture is requested but all fail."""
+        mock_page = AsyncMock()
+        mock_page.save_screenshot = AsyncMock(side_effect = Exception("Screenshot failed"))
+        mock_page.get_content = AsyncMock(side_effect = Exception("HTML failed"))
+
+        # Mock JSON write to also fail
+        monkeypatch.setattr(diagnostics_module, "_write_json_sync", MagicMock(side_effect = Exception("JSON write failed")))
+
+        output_dir = tmp_path / "diagnostics"
+        result = await capture_diagnostics(
+            output_dir = output_dir,
+            base_prefix = "test",
+            page = mock_page,
+            json_payload = {"test": "data"},
+        )
+
+        # Verify no artifacts were saved
+        assert len(result.saved_artifacts) == 0
+        assert "Diagnostics capture attempted but no artifacts were saved" in caplog.text
+
+    @pytest.mark.asyncio
+    async def test_capture_diagnostics_logs_debug_when_no_capture_requested(self, tmp_path:Path, caplog:pytest.LogCaptureFixture) -> None:
+        """Test debug is logged when no diagnostics capture is requested."""
+        output_dir = tmp_path / "diagnostics"
+
+        with caplog.at_level("DEBUG"):
+            _ = await capture_diagnostics(
+                output_dir = output_dir,
+                base_prefix = "test",
+                page = None,
+                json_payload = None,
+                copy_log = False,
+            )
+
+        assert "No diagnostics capture requested" in caplog.text
diff --git a/tests/unit/test_init.py b/tests/unit/test_init.py
index 9ffaf76..f16eb43 100644
--- a/tests/unit/test_init.py
+++ b/tests/unit/test_init.py
@@ -1,7 +1,7 @@
 # SPDX-FileCopyrightText: © Jens Bergmann and contributors
 # SPDX-License-Identifier: AGPL-3.0-or-later
 # SPDX-ArtifactOfProjectHomePage: https://github.com/Second-Hand-Friends/kleinanzeigen-bot/
-import copy, io, json, logging, os, tempfile  # isort: skip
+import copy, fnmatch, io, json, logging, os, tempfile  # isort: skip
 from collections.abc import Generator
 from contextlib import redirect_stdout
 from datetime import timedelta
@@ -12,7 +12,7 @@ from unittest.mock import AsyncMock, MagicMock, patch
 import pytest
 from pydantic import ValidationError
 
-from kleinanzeigen_bot import LOG, AdUpdateStrategy, KleinanzeigenBot, LoginState, misc
+from kleinanzeigen_bot import LOG, PUBLISH_MAX_RETRIES, AdUpdateStrategy, KleinanzeigenBot, LoginState, misc
 from kleinanzeigen_bot._version import __version__
 from kleinanzeigen_bot.model.ad_model import Ad
 from kleinanzeigen_bot.model.config_model import AdDefaults, Config, DiagnosticsConfig, PublishingConfig
@@ -388,7 +388,7 @@ class TestKleinanzeigenBotAuthentication:
 
     @pytest.mark.asyncio
     async def test_get_login_state_unknown_captures_diagnostics_when_enabled(self, test_bot:KleinanzeigenBot, tmp_path:Path) -> None:
-        test_bot.config.diagnostics = DiagnosticsConfig.model_validate({"login_detection_capture": True, "output_dir": str(tmp_path)})
+        test_bot.config.diagnostics = DiagnosticsConfig.model_validate({"capture_on": {"login_detection": True}, "output_dir": str(tmp_path)})
 
         page = MagicMock()
         page.save_screenshot = AsyncMock()
@@ -406,7 +406,7 @@ class TestKleinanzeigenBotAuthentication:
 
     @pytest.mark.asyncio
     async def test_get_login_state_unknown_does_not_capture_diagnostics_when_disabled(self, test_bot:KleinanzeigenBot, tmp_path:Path) -> None:
-        test_bot.config.diagnostics = DiagnosticsConfig.model_validate({"login_detection_capture": False, "output_dir": str(tmp_path)})
+        test_bot.config.diagnostics = DiagnosticsConfig.model_validate({"capture_on": {"login_detection": False}, "output_dir": str(tmp_path)})
 
         page = MagicMock()
         page.save_screenshot = AsyncMock()
@@ -425,7 +425,7 @@ class TestKleinanzeigenBotAuthentication:
     @pytest.mark.asyncio
     async def test_get_login_state_unknown_pauses_for_inspection_when_enabled_and_interactive(self, test_bot:KleinanzeigenBot, tmp_path:Path) -> None:
         test_bot.config.diagnostics = DiagnosticsConfig.model_validate(
-            {"login_detection_capture": True, "pause_on_login_detection_failure": True, "output_dir": str(tmp_path)}
+            {"capture_on": {"login_detection": True}, "pause_on_login_detection_failure": True, "output_dir": str(tmp_path)}
         )
 
         page = MagicMock()
@@ -453,7 +453,7 @@ class TestKleinanzeigenBotAuthentication:
     @pytest.mark.asyncio
     async def test_get_login_state_unknown_does_not_pause_when_non_interactive(self, test_bot:KleinanzeigenBot, tmp_path:Path) -> None:
         test_bot.config.diagnostics = DiagnosticsConfig.model_validate(
-            {"login_detection_capture": True, "pause_on_login_detection_failure": True, "output_dir": str(tmp_path)}
+            {"capture_on": {"login_detection": True}, "pause_on_login_detection_failure": True, "output_dir": str(tmp_path)}
         )
 
         page = MagicMock()
@@ -624,6 +624,139 @@ class TestKleinanzeigenBotAuthentication:
             assert mock_ainput.call_count == 0
 
 
+class TestKleinanzeigenBotDiagnostics:
+    @pytest.fixture
+    def diagnostics_ad_config(self) -> dict[str, Any]:
+        return {
+            "active": True,
+            "type": "OFFER",
+            "title": "Test ad title",
+            "description": "Test description",
+            "category": "161/176/sonstige",
+            "price_type": "NEGOTIABLE",
+            "shipping_type": "PICKUP",
+            "sell_directly": False,
+            "contact": {
+                "name": "Tester",
+                "zipcode": "12345",
+            },
+            "republication_interval": 7,
+        }
+
+    @pytest.mark.unit
+    @pytest.mark.asyncio
+    async def test_publish_ads_captures_diagnostics_on_failures(
+        self,
+        test_bot:KleinanzeigenBot,
+        tmp_path:Path,
+        diagnostics_ad_config:dict[str, Any],
+    ) -> None:
+        """Ensure publish failures capture diagnostics artifacts."""
+        log_file_path = tmp_path / "test.log"
+        log_file_path.write_text("Test log content\n", encoding = "utf-8")
+        test_bot.log_file_path = str(log_file_path)
+
+        test_bot.config.diagnostics = DiagnosticsConfig.model_validate({"capture_on": {"publish": True}, "output_dir": str(tmp_path)})
+
+        page = MagicMock()
+        page.save_screenshot = AsyncMock()
+        page.get_content = AsyncMock(return_value = "<html></html>")
+        page.sleep = AsyncMock()
+        page.url = "https://example.com/fail"
+        test_bot.page = page
+
+        ad_cfg = Ad.model_validate(diagnostics_ad_config)
+        ad_cfg_orig = copy.deepcopy(diagnostics_ad_config)
+        ad_file = str(tmp_path / "ad_000001_Test.yml")
+
+        with (
+            patch.object(test_bot, "web_request", new_callable = AsyncMock, return_value = {"content": json.dumps({"ads": []})}),
+            patch.object(test_bot, "publish_ad", new_callable = AsyncMock, side_effect = TimeoutError("boom")),
+        ):
+            await test_bot.publish_ads([(ad_file, ad_cfg, ad_cfg_orig)])
+
+        expected_retries = PUBLISH_MAX_RETRIES
+        assert page.save_screenshot.await_count == expected_retries
+        assert page.get_content.await_count == expected_retries
+        entries = os.listdir(tmp_path)
+        html_files = [name for name in entries if fnmatch.fnmatch(name, "publish_error_*_attempt*_ad_000001_Test.html")]
+        json_files = [name for name in entries if fnmatch.fnmatch(name, "publish_error_*_attempt*_ad_000001_Test.json")]
+        assert len(html_files) == expected_retries
+        assert len(json_files) == expected_retries
+
+    @pytest.mark.unit
+    @pytest.mark.asyncio
+    async def test_publish_ads_captures_log_copy_when_enabled(
+        self,
+        test_bot:KleinanzeigenBot,
+        tmp_path:Path,
+        diagnostics_ad_config:dict[str, Any],
+    ) -> None:
+        """Ensure publish failures copy log file when capture_log_copy is enabled."""
+        log_file_path = tmp_path / "test.log"
+        log_file_path.write_text("Test log content\n", encoding = "utf-8")
+        test_bot.log_file_path = str(log_file_path)
+
+        test_bot.config.diagnostics = DiagnosticsConfig.model_validate({"capture_on": {"publish": True}, "capture_log_copy": True, "output_dir": str(tmp_path)})
+
+        page = MagicMock()
+        page.save_screenshot = AsyncMock()
+        page.get_content = AsyncMock(return_value = "<html></html>")
+        page.sleep = AsyncMock()
+        page.url = "https://example.com/fail"
+        test_bot.page = page
+
+        ad_cfg = Ad.model_validate(diagnostics_ad_config)
+        ad_cfg_orig = copy.deepcopy(diagnostics_ad_config)
+        ad_file = str(tmp_path / "ad_000001_Test.yml")
+
+        with (
+            patch.object(test_bot, "web_request", new_callable = AsyncMock, return_value = {"content": json.dumps({"ads": []})}),
+            patch.object(test_bot, "publish_ad", new_callable = AsyncMock, side_effect = TimeoutError("boom")),
+        ):
+            await test_bot.publish_ads([(ad_file, ad_cfg, ad_cfg_orig)])
+
+        entries = os.listdir(tmp_path)
+        log_files = [name for name in entries if fnmatch.fnmatch(name, "publish_error_*_attempt*_ad_000001_Test.log")]
+        assert len(log_files) == PUBLISH_MAX_RETRIES
+
+    @pytest.mark.unit
+    @pytest.mark.asyncio
+    async def test_publish_ads_does_not_capture_diagnostics_when_disabled(
+        self,
+        test_bot:KleinanzeigenBot,
+        tmp_path:Path,
+        diagnostics_ad_config:dict[str, Any],
+    ) -> None:
+        """Ensure diagnostics are not captured when disabled."""
+        test_bot.config.diagnostics = DiagnosticsConfig.model_validate({"capture_on": {"publish": False}, "output_dir": str(tmp_path)})
+
+        page = MagicMock()
+        page.save_screenshot = AsyncMock()
+        page.get_content = AsyncMock(return_value = "<html></html>")
+        page.sleep = AsyncMock()
+        page.url = "https://example.com/fail"
+        test_bot.page = page
+
+        ad_cfg = Ad.model_validate(diagnostics_ad_config)
+        ad_cfg_orig = copy.deepcopy(diagnostics_ad_config)
+        ad_file = str(tmp_path / "ad_000001_Test.yml")
+
+        with (
+            patch.object(test_bot, "web_request", new_callable = AsyncMock, return_value = {"content": json.dumps({"ads": []})}),
+            patch.object(test_bot, "publish_ad", new_callable = AsyncMock, side_effect = TimeoutError("boom")),
+        ):
+            await test_bot.publish_ads([(ad_file, ad_cfg, ad_cfg_orig)])
+
+        page.save_screenshot.assert_not_called()
+        page.get_content.assert_not_called()
+        entries = os.listdir(tmp_path)
+        html_files = [name for name in entries if fnmatch.fnmatch(name, "publish_error_*_attempt*_ad_000001_Test.html")]
+        json_files = [name for name in entries if fnmatch.fnmatch(name, "publish_error_*_attempt*_ad_000001_Test.json")]
+        assert not html_files
+        assert not json_files
+
+
 class TestKleinanzeigenBotLocalization:
     """Tests for localization and help text."""