Project and Session Tools

Project tools establish the MCP session’s connection to Unreal Editor. Use these before asset, Blueprint, Material, PCG, or Widget tools.

Recommended Flow

1. Call loomle.status to see whether the session is already attached.
2. Call project_list to find online projects.
3. Call project_attach with the target projectId or projectRoot.
4. Call loomle to verify bridge health.
5. Call context when you want to start from the user’s active UE editor state.

If a project is missing LOOMLE support, close that project’s Unreal Editor instance and call project_install.

Tool Summary

Tool	Purpose
loomle.status	Report session attachment, project counts, update state, and observability state.
project_list	List known UE projects, online by default.
project_attach	Attach this MCP session to one online project.
project_install	Install or update project-local Plugins/LoomleBridge.
schema_inspect	Read second-level operation schemas for compact edit tools.
loomle	Check attached bridge health and runtime capabilities.
context	Read active editor context, active window, and selection.

loomle.status

Use loomle.status before attach or when a session may be stale. It is served by the client and does not require an attached runtime.

Parameters

No arguments.

Returns

Field	Meaning
loomleVersion	Running LOOMLE client version.
attached	Whether this MCP session has an attached project.
attachedProject	Attached project root, or null.
onlineProjectCount	Number of online projects discovered.
projectCount	Number of known projects.
update	Latest-version check and suggested update command.
observability	Runtime diagnostic/log state when attached.

project_list

Use project_list to discover projects that LOOMLE knows about. Online projects come from running Unreal Editor instances with LoomleBridge loaded. Offline projects come from the global LOOMLE project registry.

Parameters

Field	Required	Values	Notes
status	no	online, offline, all	Defaults to online.
includeDiagnostics	no	boolean	Adds endpoint diagnostics for troubleshooting.

Returns

projects is an array. Each project includes:

Field	Meaning
projectId	Stable LOOMLE project id. Prefer this for project_attach.
name	Project display name.
projectRoot	Project root directory.
uproject	.uproject path when known.
status	online or offline.
attachable	Whether project_attach can use this project now.
pluginInstalled	Whether Plugins/LoomleBridge exists.
pluginVersion	Installed or reported bridge version.
protocolVersion	Runtime protocol version when reported.
lastSeenAt	Last known project/runtime timestamp.
reason	Why the project is not attachable, when relevant.
diagnostics	Endpoint path and existence when requested.

Common Errors

• Invalid status: use online, offline, or all.
• Empty result: open the project in Unreal Editor, or run project_install if the project does not have LOOMLE support.

project_attach

Use project_attach after project_list returns the target project as online. Attach state is per MCP session; it is not a global active project.

Parameters

Field	Required	Notes
projectId	one of projectId or projectRoot	Preferred target from project_list.
projectRoot	one of projectId or projectRoot	Exact project root string from project_list.

Returns

Field	Meaning
attached	Always true on success.
projectId	Attached project id.
name	Attached project name.
projectRoot	Attached project root.
endpoint	Runtime endpoint used by the client.

Common Errors

• project_attach requires projectId or projectRoot: pass one target field.
• No online project matched projectId/projectRoot: call project_list with status: online and use an exact returned value.
• Project is not attachable: inspect the project’s reason and diagnostics.

project_install

Use project_install when a UE project does not yet have LOOMLE support, or when its project-local bridge needs to be synced to the active global version.

project_install copies the active global plugin cache into <ProjectRoot>/Plugins/LoomleBridge/, writes the LOOMLE project registry record, and applies the required editor support setting. It refuses to run while that project is online.

Parameters

Field	Required	Notes
projectRoot	yes	Root directory containing the .uproject file.
force	no	Recopy support even if the active version already appears installed.

Returns

Field	Meaning
projectRoot	Installed project root.
pluginPath	Destination Plugins/LoomleBridge path.
changed	Whether files were copied or updated.
previousVersion	Previous bridge version when detected.
installedVersion	Active global LOOMLE version installed into the project.
requiresEditorRestart	Whether Unreal Editor must be restarted.
message	Human-readable install result.

Common Errors

• project_install requires projectRoot: pass a project root.
• Invalid project root: choose the directory that contains the .uproject.
• Project is online: close Unreal Editor for that project and retry.
• Missing global active install state or plugin cache: reinstall or update LOOMLE globally, then retry.

schema_inspect

Use schema_inspect only when a tool description says operation-specific arguments are intentionally omitted from tools/list.

Parameters

Field	Required	Values	Notes
domain	yes	blueprint, material, pcg, widget	Tool family.
tool	yes	tool name	Must be a tool with second-level schemas.
operation	no	operation or command name	Narrows to one command schema.
include	no	summary, schema, examples, errors, notes	Defaults to summary and schema.

Supported Tools

• blueprint_graph_edit
• blueprint_member_edit
• blueprint_node_edit
• material_graph_edit
• pcg_graph_edit
• pcg_parameter_edit
• widget_tree_edit

Common Errors

• Unknown domain: use one of the four supported domains.
• Unknown tool: the selected domain does not provide second-level schemas for that tool.
• Unknown operation: call without operation first to list available operations.

loomle

Use loomle after attach to check whether the Unreal-side bridge is reachable and healthy.

Parameters

No arguments.

Returns

Field	Meaning
status	Runtime health status.
message	Error or status message.
runtime.rpcConnected	Whether the client considers the runtime endpoint reachable.
runtime.listenerReady	Whether the runtime listener is ready.
runtime.isPIE	Whether Unreal is in PIE.
runtime.editorBusyReason	Busy/unavailable reason when reported.
runtime.health	Raw bridge health payload when the fast health probe completes.
runtime.capabilities	Runtime capability payload when available.

If no project is attached, loomle returns status: "error" with editorBusyReason: "NO_PROJECT_ATTACHED".

If the runtime listener is present but the fast health probe misses its deadline, loomle keeps the runtime state ready and reports an informational HEALTH_PROBE_TIMEOUT issue instead of treating ordinary RPCs as unavailable.

context

Use context after attach when the user already has an asset open or something selected in Unreal Editor. It is the fastest way to start from visible editor state instead of guessing asset paths or graph names.

Parameters

Field	Required	Notes
resolveIds	no	Reserved id resolution input.
resolveFields	no	Reserved field selection input.

Returns

Field	Meaning
timestamp	UTC snapshot timestamp.
runtime	Project name, project file path, engine version, editor world, and PIE state.
activeWindow	Active editor window information.
context	Active Blueprint, Material, or PCG asset context when detected.
selection	Selected Blueprint nodes, Material expressions, PCG nodes, or level actors.

If context.context is generic but selection has items, use the selection’s asset paths and resolved graph refs to choose the next inspect tool.