diff --git a/kie_api/seedream45_edit.py b/kie_api/seedream45_edit.py
new file mode 100644
index 0000000..769d79b
--- /dev/null
+++ b/kie_api/seedream45_edit.py
@@ -0,0 +1,170 @@
+"""Seedream 4.5 image edit helper.
+
+Implements the Seedream 4.5 edit workflow as documented in
+`docs/KIE_API_SEEDREAM_45_EDIT_SPEC.md`.
+
+This module:
+- validates inputs
+- uploads the input image
+- creates a task
+- polls until completion (shared helper)
+- downloads and decodes the resulting image (shared helper)
+"""
+
+import json
+import time
+from typing import Any
+
+import torch
+
+from .auth import _load_api_key
+from .credits import _log_remaining_credits
+from .http import TransientKieError, requests
+from .images import _image_bytes_to_tensor
+from .jobs import _poll_task_until_complete
+from .nanobanana import _download_image, _extract_result_urls, _log
+from .upload import _image_tensor_to_png_bytes, _truncate_url, _upload_image
+
+
+CREATE_TASK_URL = "https://api.kie.ai/api/v1/jobs/createTask"
+MODEL_NAME = "seedream/4.5-edit"
+ASPECT_RATIO_OPTIONS = ["1:1", "4:3", "3:4", "16:9", "9:16", "2:3", "3:2", "21:9"]
+QUALITY_OPTIONS = ["basic", "high"]
+PROMPT_MAX_LENGTH = 3000
+
+
+def _validate_prompt(prompt: str) -> None:
+    if not prompt:
+        raise RuntimeError("Prompt is required.")
+    if len(prompt) > PROMPT_MAX_LENGTH:
+        raise RuntimeError("Prompt exceeds the maximum length of 3000 characters.")
+
+
+def _validate_options(aspect_ratio: str, quality: str) -> None:
+    if aspect_ratio not in ASPECT_RATIO_OPTIONS:
+        raise RuntimeError("Invalid aspect_ratio. Use the pinned enum options.")
+    if quality not in QUALITY_OPTIONS:
+        raise RuntimeError("Invalid quality. Use the pinned enum options.")
+
+
+def _validate_image_input(images: torch.Tensor | None) -> torch.Tensor:
+    if images is None:
+        raise RuntimeError("images input is required.")
+    if not isinstance(images, torch.Tensor):
+        raise RuntimeError("images input must be a tensor batch.")
+    if images.dim() != 4 or images.shape[-1] != 3:
+        raise RuntimeError("images input must have shape [B, H, W, 3].")
+    if images.shape[0] < 1:
+        raise RuntimeError("images input batch is empty.")
+    return images
+
+
+def _create_seedream45_edit_task(api_key: str, payload: dict[str, Any]) -> tuple[str, str]:
+    try:
+        response = requests.post(
+            CREATE_TASK_URL,
+            headers={"Authorization": f"Bearer {api_key}", "Content-Type": "application/json"},
+            json=payload,
+            timeout=30,
+        )
+    except requests.RequestException as exc:
+        raise RuntimeError(f"Failed to call createTask endpoint: {exc}") from exc
+
+    if response.status_code == 429 or response.status_code >= 500:
+        raise TransientKieError(
+            f"createTask returned HTTP {response.status_code}: {response.text}", status_code=response.status_code
+        )
+
+    try:
+        payload_json: Any = response.json()
+    except json.JSONDecodeError as exc:
+        raise RuntimeError("createTask endpoint did not return valid JSON.") from exc
+
+    if payload_json.get("code") != 200:
+        message = payload_json.get("message") or payload_json.get("msg")
+        raise RuntimeError(f"createTask endpoint returned error code {payload_json.get('code')}: {message}")
+
+    task_id = (payload_json.get("data") or {}).get("taskId")
+    if not task_id:
+        raise RuntimeError("createTask endpoint did not return a taskId.")
+
+    return task_id, response.text
+
+
+def run_seedream45_edit(
+    prompt: str,
+    images: torch.Tensor,
+    aspect_ratio: str,
+    quality: str,
+    poll_interval_s: float,
+    timeout_s: int,
+    log: bool,
+) -> torch.Tensor:
+    """Run a Seedream 4.5 image edit job.
+
+    Args:
+        prompt: Edit instruction text.
+        images: ComfyUI IMAGE tensor batch (B, H, W, 3).
+        aspect_ratio: Output aspect ratio (spec-defined enum).
+        quality: Output quality (spec-defined enum).
+        poll_interval_s: Seconds between status polls.
+        timeout_s: Maximum seconds to wait for completion.
+        log: Enable verbose logging.
+
+    Returns:
+        ComfyUI IMAGE tensor (1, H, W, 3) float32 in [0, 1].
+
+    Raises:
+        RuntimeError: For validation errors or non-retryable API/task failures.
+        TransientKieError: For retryable API/task failures.
+    """
+    _validate_prompt(prompt)
+    _validate_options(aspect_ratio, quality)
+    images = _validate_image_input(images)
+
+    api_key = _load_api_key()
+
+    if images.shape[0] > 1:
+        _log(log, f"More than 1 image provided ({images.shape[0]}); only the first will be used.")
+
+    _log(log, "Uploading edit input image...")
+    png_bytes = _image_tensor_to_png_bytes(images[0])
+    image_url = _upload_image(api_key, png_bytes)
+    _log(log, f"Input image upload success: {_truncate_url(image_url)}")
+
+    payload = {
+        "model": MODEL_NAME,
+        "input": {
+            "prompt": prompt,
+            "image_urls": [image_url],
+            "aspect_ratio": aspect_ratio,
+            "quality": quality,
+        },
+    }
+
+    _log(log, "Creating Seedream 4.5 edit task...")
+    start_time = time.time()
+    task_id, create_response_text = _create_seedream45_edit_task(api_key, payload)
+    _log(log, f"createTask response (elapsed={time.time() - start_time:.1f}s): {create_response_text}")
+    _log(log, f"Task created with ID {task_id}. Polling for completion...")
+
+    record_data = _poll_task_until_complete(
+        api_key,
+        task_id,
+        poll_interval_s,
+        timeout_s,
+        log,
+        start_time,
+    )
+
+    result_urls = _extract_result_urls(record_data)
+    _log(log, f"Result URLs: {result_urls}")
+    _log(log, f"Downloading result image from {result_urls[0]}...")
+
+    image_bytes = _download_image(result_urls[0])
+    image_tensor = _image_bytes_to_tensor(image_bytes)
+    _log(log, "Image downloaded and decoded.")
+
+    _log_remaining_credits(log, record_data, api_key, _log)
+    return image_tensor
+