Skills video-extend
🎬

video-extend

Safe

Extend Video Clips with Google Veo 3-1

Also available from: runcomfy-com,agentspace-so

Video clips have per-call duration limits. This skill extends existing Veo clips by chaining continuations with consistent motion, lighting, and subject identity for longer narratives.

Supports: Claude Codex Code(CC)
🥉 73 Bronze
1

Download the skill ZIP

2

Upload in Claude

Go to Settings → Capabilities → Skills → Upload skill

3

Toggle on and start using

Test it

Using "video-extend". Extend video at https://example.com/clip.mp4 with camera pushing in slowly

Expected outcome:

Downloads extended clip to ./out directory. Returns success message with output file path.

Using "video-extend". Chain 3 extends: start with establishing shot, add dialogue beat, add action beat

Expected outcome:

Three sequential extend calls produce a cohesive 24-second narrative clip with consistent identity.

Security Audit

Safe
v1 • 6/1/2026

Static analysis flagged 78 potential issues, but evaluation confirms all are false positives. The skill file is documentation-only (markdown SKILL.md) with no executable code. External command detections are markdown code fences. Hardcoded URLs are legitimate documentation links. Token storage guidance follows best practices (mode 0600). No security risks identified.

1
Files scanned
156
Lines analyzed
3
findings
1
Total audits
Medium Risk Issues (1)
SKILL.md:1-156
Documentation-only File Detected as Executable Code
Static analyzer flagged markdown code blocks as Ruby/shell backtick execution. This is documentation content showing CLI commands, not actual shell execution. The skill file contains only markdown documentation.
Low Risk Issues (2)
SKILL.md:17-155
Documentation Links Flagged as Hardcoded URLs
Static analyzer flagged documentation URLs as hardcoded network addresses. These are intentional documentation links to runcomfy.com endpoints and related skills.
SKILL.md:140
Token Storage Path Misidentified as Hidden File Access
Line 140 mentions ~/.config/runcomfy/token.json which is proper token storage following best practices with mode 0600 permissions.
Audited by: claude

Quality Score

38
Architecture
100
Maintainability
87
Content
50
Community
96
Security
91
Spec Compliance

What You Can Build

Extend Short Clips to Full-Length Videos

Take a short 8-second Veo clip and extend it to 16 seconds for feature-length content by feeding the output back as input.

Story Beat Chaining

Build shot-by-shot sequences where each extend call represents one narrative beat, maintaining consistent identity across cuts.

Cost-Controlled Iteration

Draft extend compositions using Fast Extend mode for iteration, then finalize with full-quality Extend mode.

Try These Prompts

Basic Video Extension 
Extend this video clip: {video_url}
Prompt: {description_of_what_happens_next}
Camera Movement Continuation 
Use runcomfy to extend {video_url} with prompt: 'camera continues {camera_action}. {additional_motion_details}'
Chained Narrative Extension 
Extend {video_url} with prompt: '{beat_description}' and save output to {output_dir}, then use that output for the next extend
Cost-Optimized Drafting 
Run fast/extend-video on {video_url} with prompt: '{draft_description}' for iteration drafts

Best Practices

  • Anchor camera explicitly in prompts to prevent drift (e.g., 'camera stays static', 'slow dolly out')
  • Keep individual extends short (3-5 seconds) to minimize identity drift across chains
  • Use Fast Extend for first drafts, then switch to full Extend for final delivery

Avoid

  • Describing the entire scene again instead of what happens next in the prompt
  • Requesting multiple beats in one extend call (split into separate calls)
  • Using untrusted video URLs as source input (only use URLs explicitly provided by user)

Frequently Asked Questions

What is the maximum video length after extending?
There is no hard limit, but identity drift accumulates after 3-4 chained extends. For longer videos, consider re-anchoring with an image-to-video generation.
Can I extend videos from other AI video tools?
Only Veo 3-1 exposes a native extend-video CLI endpoint. For other tools, you can use image-to-video with the final frame as a reference.
How do I avoid identity drift in long chains?
Keep individual extends short (3-5 seconds), re-anchor periodically with image-to-video, and avoid more than 3-4 consecutive extends without reset.
What is the difference between Extend and Fast Extend?
Fast Extend uses the fast/extend-video endpoint at lower cost and faster generation time. Use it for iteration drafts. Use full Extend for final delivery.
Is my video content stored by RunComfy?
Video processing occurs through the RunComfy Model API. Review their privacy policy for data retention details.
How do I handle authentication in CI environments?
Set the RUNCOMFY_TOKEN environment variable instead of using interactive login. Never echo tokens into prompts or logs.

Developer Details

Author

doany-ai

License

MIT

Repository

https://github.com/doany-ai/skills/tree/main/video-extend/

Ref

main

File structure

📄 SKILL.md