Fix the failed stage, not the whole film
A troubleshooting checklist for local agent video workflows.
When an AI video run fails, identify whether the problem is setup, providers, assets, timing or rendering before retrying. Keep the approved script, audio and scenes. A small reproduction of the failing stage is usually more useful than asking the agent to rebuild the entire project.
Find the stage that failed
Scroll sideways to see all columns.
| Symptom | Inspect | Next action |
|---|---|---|
| Command not found | Project README, runtime versions, PATH | Install the documented dependency; rerun the check |
| 401 or payment error | Provider key presence, account and model access | Fix access without exposing the key; no blind retries |
| Missing image or font | File path, license, response status | Use a verified local asset and rerender one frame |
| Voice and captions drift | Selected audio, timestamps and edits | Rebuild timing from the approved audio |
| Black or frozen output | Renderer log, scene frame, browser errors | Render a still or short segment |
| Clipped text or quiet speech | Actual phone playback | Repair layout or mix; keep the script and assets |
Give the agent a bounded repair task
Diagnose this failed video stage. Preserve approved script, selected audio and assets. Read the relevant log and identify the first actionable error, not just the final exit message. Show the smallest reproduction and the proposed repair. Make no paid calls unless required and approved. Verify the repaired stage with a frame or short clip before the final render. Report what changed and any remaining uncertainty.
Keep useful evidence
- Exact command and runtime version.
- First error and the preceding context, with secrets removed.
- The failing scene, frame or timecode.
- Expected result from the approved brief.
- A screenshot or short review clip showing the actual problem.
Do not paste a full environment file into a chat, issue or support email. A provider key’s presence, the provider name and a redacted error are normally enough for the first diagnosis. Keep original files until the new render has passed review.
Check the repair at the right scale
A fixed still proves a single frame, not motion or sound. A short clip checks timing, but may miss a later asset or caption. Once the relevant sample passes, watch the full final film. For FFmpeg exports, inspect the actual dimensions, duration and streams rather than trusting the filename.
When to stop retrying
If the same provider error repeats, resolve account access or a model mismatch before another generation call. If the scene repeatedly breaks because the chosen format cannot express the brief, revise the brief or change the workflow. More retries are not evidence that the direction is right.
Questions
Should I regenerate the voice after a visual fix?
Usually not. Preserve the approved voice unless the words or performance changed. Regenerating it may require new timing and captions.
Does a successful render mean the video is ready?
No. Play the final file with sound and inspect claims, captions, framing and pacing before publishing.
Keep reading
- A practical video workflow with CodexYour agent coordinates the work. A renderer produces the film.Read →
- What does an AI video workflow actually cost?The download price is only one part of the budget.Read →
- A video brief your coding agent can useOne clear job for the film, before the first render.Read →