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Control Unreal Engine 5 from your AI agent or terminal. soft-ue-cli gives any LLM — via MCP server or CLI — 60+ tools to spawn actors, edit Blueprints, inspect materials, run Play-In-Editor sessions, capture screenshots, profile performance, and more inside a running UE5 editor or packaged build.
Two ways to connect. Same 60+ tools. One pip install. One plugin copy.
- MCP server + CLI in one package -- use as an MCP server (
mcp-serve) for Claude Desktop, Cursor, Windsurf, and other MCP clients, or as a standard CLI for Claude Code, shell scripts, and CI/CD. Same 60+ tools either way. - AI-native UE automation -- purpose-built so LLM agents can read, modify, and test Unreal Engine projects without a human touching the editor.
- 60+ tools covering actors, Blueprints, materials, StateTrees, widgets, assets, PIE sessions, profiling, and more.
- LLM skill prompts -- ships with markdown workflows (e.g. Blueprint-to-C++ conversion) exposed as MCP prompts or CLI commands.
- Works everywhere UE runs -- editor, cooked builds, Windows, macOS, Linux.
- Single dependency -- only requires
httpx. Add[mcp]extra for MCP server mode. - Team-friendly -- conditional compilation via
SOFT_UE_BRIDGEenvironment variable means only developers who need the bridge get it compiled in.
pip install soft-ue-cli # CLI only
pip install soft-ue-cli[mcp] # CLI + MCP serverRun the setup command inside your LLM client (Claude Code, Cursor, etc.) — it outputs step-by-step instructions that the AI agent will follow to copy the plugin, edit your .uproject, and configure itself:
soft-ue-cli setup /path/to/YourProjectIf you're running manually (not via an LLM), follow the printed instructions yourself: copy the plugin directory, add the "Plugins" entry to your .uproject, and create the CLAUDE.md snippet.
After regenerating project files and rebuilding, launch the editor. Look for this log line to confirm the bridge is running:
LogSoftUEBridge: Bridge server started on port 8080
soft-ue-cli check-setupYou should see all checks pass:
[OK] Plugin files found.
[OK] SoftUEBridge enabled in YourGame.uproject.
[OK] Bridge server reachable.
Add to your MCP client config (Claude Desktop, Cursor, Windsurf, etc.):
{
"mcpServers": {
"soft-ue-cli": {
"command": "soft-ue-cli",
"args": ["mcp-serve"]
}
}
}The AI editor now has direct access to all 60+ UE tools and skill prompts — no terminal needed.
Claude Code
|
| (runs CLI commands in terminal)
v
soft-ue-cli (Python process)
|
| HTTP / JSON-RPC requests
v
SoftUEBridge plugin (C++ UGameInstanceSubsystem, inside UE process)
|
| Native UE API calls on the game thread
v
Unreal Engine 5 editor or runtime
The SoftUEBridge plugin is a lightweight C++ UGameInstanceSubsystem that starts an embedded HTTP server on port 8080 when UE launches. The CLI sends JSON-RPC requests to this server, and the plugin executes the corresponding UE operations on the game thread, returning structured JSON responses.
All commands output JSON to stdout (except get-logs --raw). Exit code 0 means success, 1 means error.
LLM client (Claude Code, Cursor, etc.)
|
| soft-ue-cli skills get <name>
v
Skill file (markdown shipped with CLI pip package)
|
| LLM reads instructions, type mappings, pre-filled commands
v
LLM executes soft-ue-cli commands (query-blueprint, query-blueprint-graph, ...)
|
v
LLM generates output (e.g. .h/.cpp files) following the skill's rules
Skills are markdown files at cli/soft_ue_cli/skills/*.md, shipped as package data in the pip distribution. Each skill is self-contained: workflow instructions, reference tables, example CLI commands, and verification test cases. The CLI discovers them via skills list / skills get. When running as an MCP server, the same files are exposed via the prompts/list and prompts/get protocol.
MCP Client (Claude Desktop, Cursor, Windsurf, etc.)
|
| stdio (JSON-RPC, MCP protocol)
v
soft-ue-cli mcp-serve (FastMCP server)
|
| Reuses call_tool() — HTTP/JSON-RPC
v
SoftUEBridge plugin (inside UE)
Running soft-ue-cli mcp-serve starts an MCP server over stdio. It auto-generates MCP tool schemas from the CLI's argparse parser and forwards tool calls to the UE bridge. Skills are exposed as MCP prompts. Install the optional extra: pip install soft-ue-cli[mcp].
Every command is available via soft-ue-cli <command>. Run soft-ue-cli <command> --help for detailed options.
| Command | Description |
|---|---|
setup |
Copy SoftUEBridge plugin into a UE project |
check-setup |
Verify plugin files, .uproject settings, and bridge server reachability |
status |
Health check -- returns server status |
project-info |
Get project name, engine version, target platforms, and module info |
| Command | Description |
|---|---|
spawn-actor |
Spawn an actor by class at a given location and rotation |
query-level |
List actors in the current level with transforms, filtering by class or name |
call-function |
Call any BlueprintCallable UFUNCTION on an actor |
set-property |
Set a UPROPERTY value on an actor by name |
get-property |
Read a UPROPERTY value from an actor or component using reflection |
add-component |
Add a component to an existing actor |
| Command | Description |
|---|---|
query-blueprint |
Inspect a Blueprint asset -- components, variables, functions, interfaces, event dispatchers |
query-blueprint-graph |
Inspect event graphs, function graphs, and node connections |
add-graph-node |
Add a node to a Blueprint or Material graph (supports AnimLayerFunction for ALIs) |
modify-interface |
Add or remove an implemented interface on a Blueprint or AnimBlueprint |
remove-graph-node |
Remove a node from a graph |
connect-graph-pins |
Connect two pins between graph nodes |
disconnect-graph-pin |
Disconnect pin connections (all or specific with --target-node/--target-pin) |
insert-graph-node |
Atomically insert a node between two connected nodes |
set-node-position |
Batch-set node positions for graph layout |
compile-blueprint |
Compile a Blueprint or AnimBlueprint and return the result |
compile-material |
Compile a Material, MaterialInstance, or MaterialFunction |
save-asset |
Save a modified asset to disk (with optional --checkout for source control) |
set-node-property |
Set properties on a graph node by GUID (UPROPERTY, inner structs, pin defaults) |
| Command | Description |
|---|---|
query-asset |
Search the Content Browser by name, class, or path -- also inspect DataTables |
create-asset |
Create new Blueprint, Material, DataTable, or other asset types |
delete-asset |
Delete an asset |
set-asset-property |
Set a property on a Blueprint CDO or component |
get-asset-diff |
Get property-level diff of an asset vs. source control |
get-asset-preview |
Get a thumbnail/preview image of an asset |
open-asset |
Open an asset in the editor |
find-references |
Find assets, variables, or functions referencing a given asset |
| Command | Description |
|---|---|
query-material |
Inspect Material, Material Instance, or Material Function -- parameters, nodes, connections, --parent-chain |
query-mpc |
Read or write Material Parameter Collection scalar/vector values |
| Command | Description |
|---|---|
class-hierarchy |
Inspect class inheritance chains -- ancestors, descendants, or both |
| Command | Description |
|---|---|
pie-session |
Start, stop, pause, resume PIE -- also query actor state during play |
trigger-input |
Send input events to a running game (PIE or packaged build) |
| Command | Description |
|---|---|
capture-screenshot |
Capture the editor viewport, PIE window, or a specific editor panel |
| Command | Description |
|---|---|
get-logs |
Read the UE output log with optional category and text filters |
get-console-var |
Read the value of a console variable (CVar) |
set-console-var |
Set a console variable value |
| Command | Description |
|---|---|
run-python-script |
Execute a Python script inside UE's embedded Python interpreter |
save-script |
Save a reusable Python script to the local script library |
list-scripts |
List all saved Python scripts |
delete-script |
Delete a saved script |
| Command | Description |
|---|---|
query-statetree |
Inspect a StateTree asset -- states, tasks, transitions |
add-statetree-state |
Add a state to a StateTree |
add-statetree-task |
Add a task to a StateTree state |
add-statetree-transition |
Add a transition between StateTree states |
remove-statetree-state |
Remove a state from a StateTree |
| Command | Description |
|---|---|
inspect-widget-blueprint |
Inspect UMG Widget Blueprint hierarchy, bindings, and properties |
inspect-runtime-widgets |
Inspect live UMG widget geometry during PIE sessions |
add-widget |
Add a widget to a Widget Blueprint |
| Command | Description |
|---|---|
add-datatable-row |
Add or update a row in a DataTable asset |
| Command | Description |
|---|---|
insights-capture |
Start or stop a UE Insights trace capture |
insights-list-traces |
List available trace files |
insights-analyze |
Analyze a trace file for CPU, GPU, or memory hotspots |
| Command | Description |
|---|---|
build-and-relaunch |
Trigger a full C++ rebuild and optionally relaunch the editor (--wait to monitor progress) |
trigger-live-coding |
Trigger a Live Coding compile (hot reload); waits for result by default |
| Command | Description |
|---|---|
skills list |
List all available LLM skill prompts shipped with the CLI |
skills get <name> |
Print a skill's full content to stdout for LLM consumption |
Skills are markdown prompts that teach an LLM client how to perform complex multi-step workflows using soft-ue-cli commands. They include step-by-step instructions, type mapping tables, and pre-filled CLI commands.
Available skills:
| Skill | Description |
|---|---|
blueprint-to-cpp |
Generate C++ .h/.cpp from a Blueprint asset -- Layer 1 (class scaffolding) + Layer 2 (graph logic translation) |
| Command | Description |
|---|---|
mcp-serve |
Run as an MCP (Model Context Protocol) server over stdio |
Exposes all 60+ commands as MCP tools and skills as MCP prompts. Compatible with Claude Desktop, Claude Code, Cursor, Windsurf, and other MCP clients. Requires the optional mcp extra:
pip install soft-ue-cli[mcp]soft-ue-cli spawn-actor BP_Enemy --location 100,200,50 --rotation 0,90,0soft-ue-cli query-level --class-filter StaticMeshActor --limit 50soft-ue-cli call-function BP_GameMode SetDifficulty --args '{"Level": 3}'soft-ue-cli query-blueprint /Game/Blueprints/BP_Player --include components,variablessoft-ue-cli pie-session start --mode SelectedViewport
soft-ue-cli trigger-input key --key SpaceBar
soft-ue-cli pie-session stopsoft-ue-cli capture-screenshot viewport --output screenshot.pngsoft-ue-cli add-graph-node /Game/BP_Player K2Node_CallFunction \
--properties '{"FunctionReference": {"MemberName": "PrintString"}}'
soft-ue-cli connect-graph-pins /Game/BP_Player node1 "exec" node2 "execute"soft-ue-cli modify-interface /Game/ABP_Character add ALI_Locomotion
soft-ue-cli modify-interface /Game/ABP_Character remove ALI_Locomotion
soft-ue-cli query-blueprint /Game/ABP_Character --include interfacessoft-ue-cli add-graph-node /Game/ALI_Locomotion AnimLayerFunction --graph-name FullBodysoft-ue-cli insert-graph-node /Game/ABP_Hero AnimGraphNode_LinkedAnimLayer \
{source-guid} OutputPose {target-guid} InputPose --graph-name AnimGraphsoft-ue-cli compile-blueprint /Game/ABP_Hero
soft-ue-cli save-asset /Game/ABP_Herosoft-ue-cli disconnect-graph-pin /Game/ABP_Hero {node-guid} OutputPose \
--target-node {other-guid} --target-pin InputPose# List available skills
soft-ue-cli skills list
# Feed the blueprint-to-cpp skill to your LLM client
soft-ue-cli skills get blueprint-to-cpp
# The LLM reads the skill instructions, then runs:
# soft-ue-cli query-blueprint /Game/BP_Player --include all --include-inherited
# soft-ue-cli query-blueprint-graph /Game/BP_Player --list-callables
# ...and generates the .h/.cpp files from the JSON responsessoft-ue-cli insights-capture start --channels CPU,GPU
# ... run your scenario ...
soft-ue-cli insights-capture stop
soft-ue-cli insights-analyze latest --analysis-type cpu# Install with MCP support
pip install soft-ue-cli[mcp]
# Run the MCP server (used in MCP client config, not run manually)
soft-ue-cli mcp-serveAdd to your MCP client config (e.g. claude_desktop_config.json):
{
"mcpServers": {
"soft-ue-cli": {
"command": "soft-ue-cli",
"args": ["mcp-serve"]
}
}
}| Variable | Default | Description |
|---|---|---|
SOFT_UE_BRIDGE_URL |
(none) | Full bridge URL override (e.g. http://192.168.1.10:8080) |
SOFT_UE_BRIDGE_PORT |
8080 |
Port override when using localhost |
SOFT_UE_BRIDGE |
(none) | Set to 1 to enable conditional compilation in Target.cs |
The CLI finds the bridge server using this priority:
--servercommand-line flagSOFT_UE_BRIDGE_URLenvironment variableSOFT_UE_BRIDGE_PORTenvironment variable (constructshttp://127.0.0.1:<port>).soft-ue-bridge/instance.jsonfile (searched upward from the current working directory -- written automatically by the plugin at startup)http://127.0.0.1:8080(default fallback)
If you want only specific developers to compile the bridge plugin (to avoid any overhead for artists or designers), use the SOFT_UE_BRIDGE environment variable in your Target.cs:
// MyGameEditor.Target.cs
if (Environment.GetEnvironmentVariable("SOFT_UE_BRIDGE") == "1")
{
ExtraModuleNames.Add("SoftUEBridge");
}Developers who need the bridge set SOFT_UE_BRIDGE=1 in their environment. Everyone else builds without it.
| Requirement | Supported Versions |
|---|---|
| Unreal Engine | 5.7 |
| Python | 3.10+ |
| Platforms | Windows, macOS, Linux |
| Build types | Editor, Development, Shipping (cooked/packaged) |
| Dependencies | httpx >= 0.27 (sole runtime dependency); optional mcp >= 1.2 for MCP server mode |
git clone https://github.com/softdaddy-o/soft-ue-cli
cd soft-ue-cli
pip install -e .
pytest -vsoft-ue-cli report-bug \
--title "Short bug summary" \
--description "Detailed description"Optional flags: --steps, --expected, --actual, --severity critical|major|minor, --no-system-info.
soft-ue-cli request-feature \
--title "Short feature summary" \
--description "What the feature should do"Optional flags: --use-case, --priority enhancement|nice-to-have.
soft-ue-cli submit-testimonial \
--message "Great tool for UE automation!" \
--agent-name "Claude Code" \
--rating 5Posts to GitHub Discussions with auto-collected metadata (CLI version, usage streak, top tools). A consent prompt appears before posting unless --yes is passed.
All feedback commands require GitHub auth: set GITHUB_TOKEN env var or run gh auth login.
soft-ue-cli is a Python tool that gives AI agents and developers 60+ operations to control Unreal Engine 5. It works as an MCP server (for Claude Desktop, Cursor, Windsurf, and other MCP clients) or as a standard CLI (for Claude Code, shell scripts, CI/CD). It communicates with a C++ plugin (SoftUEBridge) running inside UE via HTTP/JSON-RPC, enabling actor spawning, Blueprint editing, material inspection, Play-In-Editor sessions, screenshot capture, performance profiling, and more.
MCP clients (Claude Desktop, Cursor, Windsurf): Connect via soft-ue-cli mcp-serve. The agent sees all 60+ tools with typed schemas and skill prompts — it can directly call UE operations without going through a terminal.
Claude Code: Runs soft-ue-cli commands in the terminal. Add a CLAUDE.md file to your UE project describing available commands, and Claude Code autonomously queries your level, spawns actors, edits Blueprints, runs PIE sessions, and iterates on your game.
Yes. soft-ue-cli is a standard Python CLI. You can use it in shell scripts, CI/CD pipelines, custom automation tools, or any workflow that can invoke command-line programs. Every command outputs structured JSON, making it easy to parse and integrate.
Yes. The SoftUEBridge plugin works in both the UE editor and in cooked/packaged builds (Development and Shipping configurations). This makes it useful for automated testing of packaged games.
soft-ue-cli is actively developed against Unreal Engine 5.7.
The SoftUEBridge plugin adds a lightweight HTTP server that listens on a single port. When no requests are being made, the overhead is negligible. The server processes requests on the game thread to ensure thread safety with UE APIs. For production builds where you do not want the bridge, use conditional compilation via the SOFT_UE_BRIDGE environment variable.
Set the SOFT_UE_BRIDGE_PORT environment variable before launching UE, or use the --server flag when running CLI commands. The default port is 8080.
Yes. Each UE instance writes its port to a .soft-ue-bridge/instance.json file in the project directory. Use SOFT_UE_BRIDGE_URL or --server to target a specific instance when multiple are running.
Use query-blueprint-graph to inspect existing graph nodes, add-graph-node to create new nodes, connect-graph-pins to wire them together, and remove-graph-node to delete nodes. This enables fully programmatic Blueprint construction -- useful for AI-driven development and automated testing.
Unreal Engine's built-in Remote Control API focuses on property access and preset-based workflows. soft-ue-cli provides a broader command set specifically designed for AI coding agents -- including Blueprint graph editing, StateTree manipulation, PIE session control, UE Insights profiling, widget inspection, and asset creation -- with a simpler setup process (one pip install, one plugin copy).
Run pip install soft-ue-cli[mcp] to install MCP support, then add the server to your MCP client config. For Claude Desktop, add to claude_desktop_config.json:
{
"mcpServers": {
"soft-ue-cli": {
"command": "soft-ue-cli",
"args": ["mcp-serve"]
}
}
}The MCP server exposes all 60+ commands as MCP tools and skills as MCP prompts. The AI editor can then directly call UE operations without going through the terminal.
| soft-ue-cli | unreal-mcp, ue5-mcp, etc. | |
|---|---|---|
| Tools | 60+ | 10–49 |
| Coverage | Blueprints, materials, StateTrees, widgets, PIE, profiling, DataTables, CVars, Live Coding | Varies; most cover actors + basic assets |
| LLM skill prompts | Yes (MCP prompts + CLI) | No |
| CLI mode | Yes — shell scripts, CI/CD, Claude Code | MCP-only |
| Setup | pip install soft-ue-cli[mcp] + copy one plugin |
Varies; often requires custom C++/Python scripting |
soft-ue-cli is free, open-source, and maintained by one person. If it saves you hours of manual editor work or helps your AI workflow, consider supporting continued development:
- Sponsor on GitHub — recurring or one-time
- Buy me a coffee on Ko-fi — quick one-time donation
Using soft-ue-cli in your project? Share your experience — I'd love to hear about it.
- UE 5.8 support
- More LLM skills (Material-to-HLSL, Animation Blueprint automation)
- Visual diff for Blueprint changes
- CI/CD integration examples
MIT License. See LICENSE for details.
- PyPI: pypi.org/project/soft-ue-cli
- GitHub: github.com/softdaddy-o/soft-ue-cli
- Claude Code: docs.anthropic.com/en/docs/claude-code