--- name: klingai-video-extension description: 'Extend video duration using Kling AI continuation. Use when creating longer videos from shorter clips or building sequences. Trigger with phrases like ''klingai extend video'', ''kling ai video continuation'', ''klingai longer video'', ''extend klingai clip''. ' allowed-tools: Read, Write, Edit, Bash(npm:*), Grep version: 1.18.0 license: MIT author: Jeremy Longshore tags: - saas - kling-ai - video-extension - continuation compatibility: Designed for Claude Code --- # Kling AI Video Extension ## Overview Extend an existing video by appending additional seconds. The extension endpoint takes the `task_id` of a completed video and generates a seamless continuation. **Endpoint:** `POST https://api.klingai.com/v1/videos/video-extend` ## Request Parameters | Parameter | Type | Required | Description | |-----------|------|----------|-------------| | `task_id` | string | Yes | Task ID of the completed source video | | `prompt` | string | No | Motion/scene description for extension | | `duration` | string | No | Extension length: `"5"` (default) | | `mode` | string | No | `"standard"` or `"professional"` | | `model_name` | string | No | Default: `"kling-v2-master"` | | `callback_url` | string | No | Webhook for completion | ## Basic Extension ```python import jwt, time, os, requests BASE = "https://api.klingai.com/v1" def get_headers(): ak, sk = os.environ["KLING_ACCESS_KEY"], os.environ["KLING_SECRET_KEY"] token = jwt.encode( {"iss": ak, "exp": int(time.time()) + 1800, "nbf": int(time.time()) - 5}, sk, algorithm="HS256", headers={"alg": "HS256", "typ": "JWT"} ) return {"Authorization": f"Bearer {token}", "Content-Type": "application/json"} # Step 1: Generate the initial 5s video initial = requests.post(f"{BASE}/videos/text2video", headers=get_headers(), json={ "model_name": "kling-v2-master", "prompt": "A rocket launching from a desert landscape, cinematic", "duration": "5", "mode": "standard", }).json() initial_task_id = initial["data"]["task_id"] # Wait for completion... # (poll until task_status == "succeed") # Step 2: Extend by 5 more seconds extension = requests.post(f"{BASE}/videos/video-extend", headers=get_headers(), json={ "task_id": initial_task_id, "prompt": "The rocket ascends through clouds into the stratosphere", "duration": "5", "mode": "standard", }).json() ext_task_id = extension["data"]["task_id"] # Step 3: Poll extension task while True: time.sleep(15) result = requests.get( f"{BASE}/videos/video-extend/{ext_task_id}", headers=get_headers() ).json() if result["data"]["task_status"] == "succeed": extended_url = result["data"]["task_result"]["videos"][0]["url"] print(f"Extended video: {extended_url}") break elif result["data"]["task_status"] == "failed": print(f"Failed: {result['data']['task_status_msg']}") break ``` ## Chain Multiple Extensions ```python def chain_extensions(initial_task_id: str, prompts: list[str], duration: str = "5", mode: str = "standard") -> list[str]: """Chain multiple extensions to build a longer video.""" current_task_id = initial_task_id video_urls = [] for i, prompt in enumerate(prompts): print(f"Extension {i + 1}/{len(prompts)}: submitting...") # Submit extension r = requests.post(f"{BASE}/videos/video-extend", headers=get_headers(), json={ "task_id": current_task_id, "prompt": prompt, "duration": duration, "mode": mode, }).json() ext_task_id = r["data"]["task_id"] # Poll for completion while True: time.sleep(15) result = requests.get( f"{BASE}/videos/video-extend/{ext_task_id}", headers=get_headers() ).json() status = result["data"]["task_status"] if status == "succeed": url = result["data"]["task_result"]["videos"][0]["url"] video_urls.append(url) current_task_id = ext_task_id # next extension chains from this print(f"Extension {i + 1} complete: {url}") break elif status == "failed": raise RuntimeError(f"Extension {i + 1} failed: {result['data']['task_status_msg']}") return video_urls ``` ## Usage: Build a 20-Second Video ```python # Generate initial 5s initial_r = requests.post(f"{BASE}/videos/text2video", headers=get_headers(), json={ "model_name": "kling-v2-master", "prompt": "Morning sunrise over a mountain lake, mist rising", "duration": "5", "mode": "standard", }).json() initial_id = initial_r["data"]["task_id"] # ... poll until complete ... # Chain 3 more extensions = 5 + 5 + 5 + 5 = 20 seconds total extensions = chain_extensions(initial_id, [ "Sun rises higher, birds begin flying across the lake", "A deer approaches the water's edge to drink", "Wide shot pulling back to reveal the full mountain range", ]) ``` ## Cost Each extension costs the same as a new generation: | Extension Duration | Standard | Professional | |-------------------|----------|-------------| | 5 seconds | 10 credits | 35 credits | A 20-second video (initial + 3 extensions) costs 40 credits in standard mode. ## Error Handling | Error | Cause | Fix | |-------|-------|-----| | Invalid `task_id` | Source task doesn't exist | Verify task_id is from a completed generation | | Source not complete | Extending a task still processing | Wait for source task to reach `succeed` status | | Extension failed | Prompt conflict with source | Align extension prompt with original scene | ## Prerequisites - A completed, rights-cleared or synthetic source draft, approved extension brief, authorized workspace and credit budget, policy review, draft-only destination, and a rollback/removal owner. ## Instructions 1. Confirm source ownership, completion state, and approved continuity brief before creating an extension; do not use private, unlicensed, or policy-restricted material. 2. Submit one watermarked draft canary within the approved duration and credit cap, then verify policy, rights, quality, and destination controls. 3. Halt on continuity, policy, rights, or budget drift and delete the extension task instead of publishing it. 4. Promote only after owner approval; retain a redacted receipt and remove temporary assets at the agreed retention boundary. ## Output Produce an extension receipt with source task reference, rights classification, mode/duration, credit estimate, policy review, draft destination, approver, retention/removal reference, and task ID. Exclude prompts, identities, and asset URLs. ## Examples `source=synthetic-task-42; rights=cleared; duration=5s; mode=standard; policy=pass; destination=draft-only; cleanup=24h` is safe for review. ## Resources - [Video Extension API](https://app.klingai.com/global/dev/document-api/apiReference/model/videoExtension) - [Developer Portal](https://app.klingai.com/global/dev)