melt-7 MCP Server

An MCP server exposing melt-7 (the MLT Multimedia Framework's CLI rendering engine -- the same backend Kdenlive uses) for agentic video editing/composition: build a multi-track timeline with clips, transitions, filters, and text overlays, then render it to MP4.

Requirements

• melt-7 and ffprobe/ffmpeg on PATH (Fedora: dnf install mlt)
• Python 3.10+

pip install -r requirements.txt

Running

python mcp_server.py

Serves MCP over streamable HTTP on http://0.0.0.0:8001/mcp (port 8001, to avoid colliding with the wan2_2_t2v server on 8000 if both run on the same host).

Project model

Each call to create_project creates a project directory under projects/<id>/ holding project.mlt (the authoritative MLT XML, hand-rolled to a flat schema rather than Kdenlive's nested per-track-tractor convention), meta.json (display name/profile bookkeeping), and a renders/ directory for rendered output. Every tool re-reads project.mlt fresh and atomically rewrites it, so state survives server restarts -- there is no in-memory project cache.

Tools

Tool	Purpose
create_project(name, profile)	Start a new project at a given MLT profile (resolution/fps)
list_projects()	List all projects with track/clip counts
get_project_xml(project_id)	Raw MLT XML + human-readable summary
delete_project(project_id)	Delete a project and its renders
probe_clip(file_path)	ffprobe a media file (duration, resolution, fps, codecs)
add_track(project_id, kind, position)	Add a track to the timeline
remove_track(project_id, track_id)	Remove a track
add_clip(project_id, track_id, source, clip_in, clip_out, position)	Place a clip (file path or color:/noise: generator)
trim_clip(project_id, track_id, clip_index, clip_in, clip_out)	Change a clip's in/out points
move_clip(project_id, track_id, clip_index, new_position, new_track_id)	Move a clip (leaves a blank gap behind)
remove_clip(project_id, track_id, clip_index)	Remove a clip (leaves a blank gap)
add_transition(project_id, track_a, track_b, service, properties)	Composite/wipe/mix between two tracks
add_filter(project_id, target, service, properties, clip_index)	Attach a filter to a track, clip, or the whole project
remove_filter(project_id, filter_id)	Remove a filter
add_text_overlay(project_id, track_id, text, ...)	Convenience wrapper for a qtext title clip
query_services(kind, service_id)	Discover available producers/filters/transitions/consumers/profiles
set_raw_xml_property / remove_raw_xml_property / inject_raw_xml	Escape hatch for anything the above don't cover
render_project(project_id, output_name, vcodec, acodec, extra_args, timeout_seconds)	Render the timeline to MP4 (synchronous)

Notes on reliability

melt-7's process exit code is not a reliable success signal -- it can exit 0 while logging a "failed to load producer" error and silently substituting a blank clip. render_project verifies success independently: the output file must exist, be ffprobe-readable, have a duration close to the project's expected duration, and stdout/stderr must contain no known failure markers.