animation-blueprint

🧠 Brains complement: IF an unreal-engine-skills-manager tool (external MCP) exists in this session, call it with {action: "load", skill: "animation-system"} for UE domain knowledge on this topic — correct APIs, architecture, best practices — and treat it as the rubric for any review / "best practices" question. If no such tool is available (e.g. running under Claude Code or Codex without that MCP), skip this line entirely and proceed with this skill alone — do NOT attempt the call.

Animation Blueprint Skill

Loading skills: skills load through the engine's AgentSkillToolset (ListSkills/GetSkills) — there is no vibeue-skills-manager tool. Run VibeUE services with execute_python_code (unreal.AnimGraphService.<method>()); reach engine toolsets with call_tool.

An AnimBP is a Blueprint. The state-machine/AnimGraph authoring here is VibeUE AnimGraphService (intact). For its variables and compile, note VibeUE's BlueprintService was trimmed: variable creation and blueprint compile moved to the engine toolset editor_toolset.toolsets.blueprint.BlueprintTools (add_variable, compile_blueprint), called via call_tool. BlueprintService still has list_variables, get_variable_info, set_variable_default_value, variable_exists, components, and overridable functions. Bool fields on info structs drop the C++ b prefix in Python — use is_pure, is_output, already_overridden (NOT b_is_pure); call discover_python_class to confirm field names rather than guessing.

⚠️ #1 GOTCHA — Transitions need a RULE or they NEVER fire

add_transition() only draws the arrow between two states. The transition's rule graph starts empty, which evaluates to false, so the transition is inert — the state machine will never move. You MUST set a rule on every transition:

import unreal
abp = "/Game/ABP_Character"
BT  = "editor_toolset.toolsets.blueprint.BlueprintTools"

# 1) Add the bool/float variable the rule reads, then COMPILE so it resolves.
#    Variable creation + compile are ENGINE BlueprintTools (call_tool), not VibeUE:
call_tool(BT, "add_variable", {"blueprint": {"refPath": abp}, "variable_name": "bIsDead", "variable_type": "bool"})
call_tool(BT, "compile_blueprint", {"blueprint": {"refPath": abp}})
# (Run describe_toolset(BT) for exact arg names.)

# 2) Draw the transition (VibeUE AnimGraphService)
unreal.AnimGraphService.add_transition(abp, "Locomotion", "Idle", "Dead", 0.2)

# 3) Give it a rule — THIS is what makes it fire
unreal.AnimGraphService.set_transition_rule_from_bool(abp, "Locomotion", "Idle", "Dead", "bIsDead")