RV MCP Server

MCP (Model Context Protocol) server that bridges AI assistants like Claude to Autodesk/Tweak RV, the industry-standard media review application. Control playback, compare shots, adjust color grading, and manage review sessions — all through natural language.

No plugin required inside RV. Uses RV's built-in network listener with Mu scripting via remote-eval.

Requirements

• OpenRV (or RV 2022.3.1+) with network mode enabled

• Python 3.10+

• uv package manager

Quick Start

1. Start RV with networking

Enable networking in RV via RV → Networking → Enable Network (default port 45124).

Or from the command line:

rv -network -networkPort 45124

2. Install and register

Claude Code (CLI):

claude mcp add --scope user rv-mcp -- uv run --no-sync --directory /path/to/RV_MCP rv-mcp

Note: --no-sync prevents file lock conflicts when multiple Claude sessions share the same MCP server. Run uv sync manually after changing dependencies.

Claude Desktop (~/.claude.json):

{
  "mcpServers": {
    "rv-mcp": {
      "command": "uv",
      "args": ["run", "--no-sync", "--directory", "/path/to/RV_MCP", "rv-mcp"]
    }
  }
}

Environment variables (optional):

3. Use it

Ask Claude to load media, control playback, compare shots, or adjust colors. The server translates natural language into RV commands automatically.

Architecture

Claude (stdio/MCP) --> FastMCP Server --> RV Network Protocol (TCP:45124) --> RV

The server maintains a persistent TCP connection to RV using a custom protocol based on RV's RvCommunicator. Key design decisions:

• Persistent connection with automatic reconnection on socket loss

• Thread-safe via threading.Lock for concurrent tool calls

• Clean shutdown via atexit handler that sends DISCONNECT (without this, RV rejects future connections)

• Mu string handling — return values are automatically unquoted and unescaped

Protocol Flow

1. Connect TCP to 127.0.0.1:45124
2. Send: NEWGREETING <len> rv-mcp rvController
3. Send: PINGPONGCONTROL 1 0          (disable heartbeat)
4. Recv: NEWGREETING <len> <rv-name>   (consume RV's greeting)
5. For each command:
   Send: MESSAGE <len> RETURNEVENT remote-eval * { require commands; <mu_code> }
   Recv: MESSAGE <len> RETURN <value>
6. On shutdown:
   Send: MESSAGE <len> DISCONNECT

OCIO Color Management

The server includes full OCIO v2 support. When $OCIO is set, RV can match the exact display transform used by your DCC apps (3ds Max/Redshift, Nuke, etc.).

Auto-configuration

An rv_ocio_setup.py script is included that auto-configures OCIO when RV loads media:

• EXR/HDR/TX files are auto-detected as scene-linear (ACEScg via the scene_linear role)

• Display transform is set from the config's defaults (e.g., sRGB / ACES 1.0 SDR-video)

• Chromaticity metadata in EXRs is matched against the active config's color spaces

To install, copy rv_ocio_setup.py to your RV support path:

# Windows
copy rv_ocio_setup.py %APPDATA%\RV\Python\

# Linux/macOS
cp rv_ocio_setup.py ~/.rv/Python/

RV's built-in ocio_source_setup package will detect and use this override automatically.

Manual OCIO via MCP

Redshift + RV Color Matching

If you use Redshift's OCIO config ($OCIO = C:\ProgramData\redshift\Data\OCIO\config.ocio), note that its file rules mark EXRs as "Raw". The rv_ocio_setup.py script overrides this by detecting float formats as scene-linear, ensuring the ACES tonemapper is applied in RV just like in Redshift's Render View.

Tools (47 total)

Execute (1)

OCIO (6)

Execute (1)

Playback (17)

Sources (7)

Compare (4)

Color (12)

Usage Examples

Load and review footage

"Load the EXR sequence at /shots/sh010/comp/sh010_comp.1-100#.exr"
"Play it back at 24fps"
"Go to frame 50"
"Set in point at 20 and out point at 80"

Compare two versions

"Load both /shots/sh010/comp_v1.mov and /shots/sh010/comp_v2.mov"
"Switch to stack view"
"Set composite to difference mode"
"Toggle the wipe to compare side by side"

Color correction

"Apply CDL with slope [1.1, 0.95, 1.0] and saturation 1.2"
"Load the ACES LUT from /luts/sRGB.cube"
"Set exposure to 0.5"
"Show me the current color settings"

Advanced (raw Mu)

"Execute this Mu code: { require commands; let s = sources(); string(s.size()); }"

Project Structure

RV_MCP/
├── pyproject.toml          # Package config, entry point, dependencies
├── README.md
├── .gitignore
└── src/
    ├── __init__.py
    ├── server.py           # FastMCP server + RvClient instantiation
    ├── rv_client.py        # Persistent TCP client (RV network protocol)
    └── tools/
        ├── __init__.py
        ├── execute.py      # execute_mu — raw Mu escape hatch
        ├── playback.py     # 17 playback/transport tools
        ├── sources.py      # 7 source & session tools
        ├── compare.py      # 4 view/compare tools
        ├── color.py        # 12 color/LUT/CDL tools
        └── ocio.py         # OCIO v2 color management tools

Troubleshooting

"Could not connect to RV"

• Ensure RV is running with the -network flag

• Check that port 45124 is not blocked by a firewall

• Use -networkPort 45124 to explicitly set the port

RV rejects connections after a crash

If the server exits without sending DISCONNECT, RV may reject new connections. Restart RV to clear the state. The server includes an atexit handler to prevent this under normal operation.

Mu code errors

• Always wrap code blocks in { require commands; ... }

• Mu evaluates both branches of if/then/else — avoid property access on nodes that may not exist

• File paths must use forward slashes; escape_mu_string() handles this automatically

Timeout errors

The default timeout is 30 seconds. If Mu code takes longer (e.g., loading large sequences), it may time out. Use execute_mu for long operations and consider breaking them into smaller steps.

Development

# Install dependencies
uv sync

# Run the server directly
uv run rv-mcp

# Run with debug logging
uv run python -m src.server

License

MIT