How to replace a character in a video with Claude MCP and Medux

Use Claude and Medux through MCP to replace a video character using a source clip and reference character image. This guide keeps file roles and constraints in context, reviews the proposed call, and validates the returned result.

Input: MP4 videoReference: JPG character imageOutput: replaced-character video
Preview of the source character video
The source clip used in the tutorial before the character is replaced.

Claude-specific workflow

Run AI Video Character Replacement as a Claude MCP workflow

Keep the goal, source assets, and constraints together in the conversation. Ask Claude to restate the source video, reference character image, and replacement instructions before proposing medux_video_character_replacement. That context checkpoint makes the file roles and desired outcome easy to correct before any Medux call is approved.

Claude prompt pattern

Using the assets and requirements in this conversation, help me replace a character in a video with Medux MCP.
Restate which input fulfills each role: the source video, reference character image, and replacement instructions.
Propose the medux_video_character_replacement call and summarize its arguments before asking for approval.
When it finishes, return the character-replaced MP4 with a checklist confirming that the intended character is replaced consistently and the video plays from start to finish.

Context checkpoint

Have Claude summarize the intended transformation, identify every source asset by role, and list the important constraints. Review that summary together with the proposed tool arguments; correct the conversation first if a file, order, time range, or setting is ambiguous.

Result verification

Keep the Medux task ID in the conversation while Claude checks progress. When processing ends, ask for the character-replaced MP4 plus a concise validation checklist confirming that the intended character is replaced consistently and the video plays from start to finish.

Workflow at a glance

Claude handles the orchestration. Medux handles the AI video processing.

1. Describe the replacement
2. Upload both assets
3. Start the Medux task
4. Poll until complete
5. Open the output

Prerequisites

FilesA source video such as character.mp4 and a reference character image such as character.jpg.
ConnectionClaude with the Medux MCP server enabled and permission to call Medux tools.
Example project folder/Users/your-name/projects/medux-character-replacement/
├── character.mp4
└── character.jpg

Step-by-step guide

01

Give Claude one clear instruction

Describe the target video, the reference image, and the desired outcome in one request. Claude can then plan the workflow and choose the correct Medux tools.

PromptPerform a video character replacement by replacing the person in
character.mp4 with the character from character.jpg.
Upload the files using curl commands.
Claude request for video character replacement
The request names both assets and makes the desired replacement explicit.
02

Create upload URLs and send both files

Claude calls medux_file_create_upload_url for the MP4 and JPG, then uploads them to the returned signed URLs. In the recorded workflow, Claude uses curl because direct uploads are restricted by the sandbox network.

Upload patterncurl -X PUT   -H "Content-Type: video/mp4"   --data-binary @"/path/to/character.mp4"   "SIGNED_UPLOAD_URL_FOR_VIDEO"

curl -X PUT   -H "Content-Type: image/jpeg"   --data-binary @"/path/to/character.jpg"   "SIGNED_UPLOAD_URL_FOR_IMAGE"

Long paths and signed URLs wrap inside the code block, so the command stays within the page width on desktop and mobile.

Curl upload commands for the source video and reference image
A successful signed-URL upload normally returns an empty HTTP 200 response.
03

Start the Medux character-replacement job

After both uploads succeed, Claude passes the uploaded file references to medux_video_character_replacement. Medux then analyzes the source clip, follows the original motion, and renders the new character into the scene.

Keep the instruction focused. The reference image defines the new character, while the source video provides motion, timing, camera movement, and scene structure.
Claude calling the Medux video character replacement tool
Claude starts the Medux task immediately after confirming the uploads.
04

Let Claude monitor the render

The Medux task may remain queued or processing for several minutes. Claude uses medux_task_query to check the status repeatedly, so you do not need to manually refresh another dashboard.

Status logicQUEUED → PROCESSING → COMPLETED

If the task is still processing:
wait briefly, then call medux_task_query again.
Claude polling the Medux task status
In the tutorial, Claude continues polling about every 40 seconds until the task finishes.
05

Open the completed video

When the task reaches COMPLETED, Claude returns the output link. Open it to review the replacement, confirm that motion and scene continuity are preserved, and save the final file.

Result returned by Medux

Completed character replacement result link in Claude
The final response contains a direct result link after the Medux render succeeds.

Example result

src / tgt / rst demonstration

Below is the complete character-replacement example: src is the original source video, tgt is the reference character, and rst is the final video generated by Medux.

src
Source video. Original source video used for character replacement.
tgt
Reference character image for the Medux character replacement example
Target character. Reference character image used by Medux.
rst
Generated result. Final character-replacement video generated by Medux.

Why use Medux through MCP?

The workflow stays inside Claude: one prompt, automatic file preparation, tool selection, task submission, status checks, and result retrieval. You avoid building a separate upload interface or writing a custom API client for every video operation.

Natural-language control
Reusable automation
No dashboard switching

Quick recap

character.mp4 + character.jpg
        ↓
Claude locates the files
        ↓
Medux creates signed upload URLs
        ↓
curl uploads both assets
        ↓
medux_video_character_replacement
        ↓
medux_task_query until COMPLETED
        ↓
Download the replaced-character video

Explore related workflows

Continue with a nearby Medux workflow or compare how the same task works across Claude MCP and Codex MCP.

Related Medux tutorials

How to Replace a Video Character with Codex MCP and MeduxHow to Change an Outfit in an Image with Claude MCP and MeduxHow to Swap Faces in an Image with Claude MCP and MeduxHow to Swap a Head in an Image with Claude MCP and MeduxHow to Restore Old Photos with Claude MCP and Medux

Quick answer

How do I run AI Video Character Replacement with Claude MCP?

Claude can use medux_video_character_replacement through Medux MCP to replace a video character using a source clip and reference character image. The workflow keeps input roles and constraints in context, reviews the proposed call, and checks the returned result.

What does this Medux tutorial cover?

Claude can use medux_video_character_replacement through Medux MCP to replace a video character using a source clip and reference character image. The workflow keeps input roles and constraints in context, reviews the proposed call, and checks the returned result.

Related topics: AI Video Character Replacement · AI Video Character Replacement with Claude MCP · Medux MCP tutorial

Build with the API

API reference for this workflow

Use the API reference to automate this workflow, or follow the matching guide in our official GitHub repository.