OpenMontage is an open-source, agentic video production system that turns an AI coding assistant into a full video production studio. It offers 12 production pipelines, over 100 tools, and 700+ agent skill and knowledge files covering research, scripting, asset generation, editing, and final composition. Users describe what they want in plain language and the agent handles the entire workflow, supporting both AI-generated and real stock footage paths. OpenMontage integrates with providers like fal.ai, ElevenLabs, Runway, and HeyGen, while also functioning fully offline with free tools such as Piper TTS, FFmpeg, Remotion, and open stock archives. A local Backlot dashboard visualizes the production pipeline in real time and includes an approval gate for reviewing generated assets before final render.