Error Codes - Blueprint AI Assistant

Part of the BlueprintAIAssistant documentation. For the full AI integration reference, see AI Guide.

All BAA verbs return structured JSON. On failure the response includes an errorCode field:

{"success": false, "error": "Human-readable message", "errorCode": "ASSET_NOT_FOUND"}

The error string provides context (asset path, pin name, etc.). The errorCode is a machine-stable identifier you can match on programmatically.

Core Blueprint Errors#

Code	Meaning
`ASSET_NOT_FOUND`	Asset does not exist at the given path
`GRAPH_NOT_FOUND`	Named graph not found in the Blueprint
`NODE_NOT_FOUND`	Node GUID or title lookup failed
`PIN_NOT_FOUND`	Pin name not found on a node
`VARIABLE_NOT_FOUND`	Blueprint variable name not found
`PROPERTY_NOT_FOUND`	UProperty or CDO property not found
`TYPE_MISMATCH`	Value or connection type incompatible
`COMPILE_ERROR`	Blueprint compilation failed
`SAVE_ERROR`	Asset package save to disk failed
`INVALID_ARGS`	Missing or malformed verb arguments
`UNKNOWN_VERB`	Verb name not recognized
`UNKNOWN_TYPE`	Node type, variable type, etc. not recognized
`INTERNAL_ERROR`	Unexpected failure (catch-all)
`BATCH_ERROR`	One or more batch operations failed
`NODE_CREATE_FAILED`	Node construction/spawning failed
`CONNECTION_FAILED`	Pin connection could not be made
`SET_DEFAULT_FAILED`	Setting pin default value failed
`NO_EVENT_GRAPH`	Blueprint has no EventGraph

Code	Meaning
`ROW_NOT_FOUND`	DataTable row name not found
`PARAM_NOT_FOUND`	Material/Niagara parameter not found
`KEY_NOT_FOUND`	Blackboard key not found
`UNSUPPORTED_ASSET`	Asset type not supported by the verb

Code	Meaning
`FUNCTION_NOT_FOUND`	Function graph not found
`INTERFACE_NOT_FOUND`	Interface class not found or not implemented
`COMPONENT_NOT_FOUND`	SCS component not found by name
`DISPATCHER_NOT_FOUND`	Event dispatcher not found

Code	Meaning
`NO_SCHEMA`	Blueprint has no valid skeleton/schema
`NO_GENERATED_CLASS`	Blueprint's generated class is null
`NO_CDO`	Class Default Object could not be obtained

Code	Meaning
`RENAME_FAILED`	Asset rename/move operation failed
`DUPLICATE_FAILED`	Asset duplication failed
`DELETE_BLOCKED`	Deletion blocked by reference check (use `-force` to override)
`DELETE_FAILED`	Deletion failed even with force
`HAS_REFERENCERS`	Asset has incoming references (informational)

Code	Meaning
`INDEX_OUT_OF_BOUNDS`	Array index exceeded valid range
`NOT_AN_ARRAY`	Property is not an array type

Code	Meaning
`EXPRESSION_NOT_FOUND`	Material expression node not found
`TRACK_NOT_FOUND`	Sequencer track not found
`SECTION_NOT_FOUND`	AnimMontage or Sequencer section not found
`WIDGET_NOT_FOUND`	Widget not found in widget tree
`BT_NODE_NOT_FOUND`	BehaviorTree node not found
`BB_KEY_NOT_FOUND`	Blackboard key not found

The most frequent error. Causes and fixes:

Wrong path prefix. Asset paths must start with /Game/, not a filesystem path. Example: /Game/Blueprints/BP_MyActor, not Content/Blueprints/BP_MyActor.
Included .uasset extension. Asset paths must omit the file extension.
Case mismatch. Asset paths are case-sensitive. Use list to search: -verb=list -path=/Game/ -name=MyAsset.
Asset not saved. If the asset was just created in the editor, save it before running BAA.

Stale GUID. Node GUIDs change when a node is deleted and re-created. Re-export with --format=detail to get current GUIDs.
Title lookup ambiguity. If searching by title, multiple nodes may share the same display name. Use the 8-character GUID instead.

Case sensitivity. Pin names are case-sensitive and must match exactly. Use read-graph -format=detail to list the exact pin names on nodes.
Execution pins. The default execution pin names are execute (input) and then (output), not exec or out.
Wildcard pins. Some nodes create pins dynamically. Add the node first, then query its pins before connecting.

Incompatible pin types. You cannot connect a float output to a string input without an explicit conversion node.
Wrong variable type string. Variable types use UE internal names: Boolean, Integer, Float, Name, String, Vector, Rotator, Transform. Object types use the class path.

Missing connections. Required pins (execution or data) may be disconnected. Use validate before compile to get specific diagnostics.
Orphaned nodes. Nodes left from a previous edit may reference deleted variables or functions. Use find-nodes to locate and remove-node to clean up.

Missing required arguments. Each verb has mandatory parameters. Run -verb=help -about=<verb> to see the full argument list.
Malformed JSON in batch mode. Validate your JSON externally. JSON requires double quotes, no trailing commas, and no single-quoted strings.

Partial failure. The batch completed but some operations failed. Check the results array in the response. Each entry has its own success and errorCode fields.
$N reference to a failed op. If operation $3 failed and operation $5 references $3, operation $5 will also fail. Fix the upstream operation first.

Type mismatch. The source and target pins have incompatible types. Check both pin types with read-graph -format=detail.
Already connected. Some pins (especially execution pins) allow only one connection. Disconnect the existing connection first with disconnect.

File is read-only. If using Perforce, the .uasset must be checked out for edit (p4 edit) before BAA can save.
File locked by another process. Close the asset in the editor or check p4 opened for other users holding the lock.

Typo or wrong casing. Verbs use lowercase with hyphens: add-node, set-pin-default, read-graph. Run -verb=help for the full list.

Zero-indexed arrays. Array indices start at 0. Use array-count to check the valid range before calling array-get, array-set, or array-remove.

Display name vs. variable name. Components have both a display name (shown in the editor) and a variable name (used in code). BAA uses the variable name. Use read-components to list the exact names.

Blueprint not compiled. The CDO is only available after a successful compile. Run compile before read-cdo or set-cdo-property.
Abstract or interface class. Some classes do not have a CDO. Check that the Blueprint is a concrete class (Actor, Object, etc.).

Other assets reference this one. BAA blocks deletion by default to prevent broken references. Use the error message to see which assets hold references.
Force deletion. Pass -force to override the safety check. This leaves dangling references that must be cleaned up manually.