Unreal Behavior Trees

What it does

When your agent uses it

• Creating enemy/NPC AI
• BTService nodes
• The user mentions Behavior Tree

Example prompts

• “/unreal-behavior-trees”

Requirements

• Compatibility (from SKILL.md): Unreal Engine 5.4+ (AIModule; Behavior Tree + Blackboard; NavMesh for movement)

Workflow steps

3 steps, taken from the step headings in SKILL.md.

1. 1AIController that runs the tree (C++)
2. 2A priority tree (node structure)
3. 3Updating the Blackboard from code (e.g. on seeing the player)

What it can do on your machine

Read from SKILL.md and the folder at commit eac84e0. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  No scripts in the folder and no shell commands in SKILL.md (its code samples are cpp).

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  Hosts in commands or code, which the agent is likely to contact:

  • dev.epicgames.com

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

• Compatibility

  Unreal Engine 5.4+ (AIModule; Behavior Tree + Blackboard; NavMesh for movement)

  From compatibility in the SKILL.md frontmatter.

Context cost

Unreal Behavior Trees loads about 1.4k tokens when it runs, and up to ~2.4k if it reads all its reference files. Until then it costs about 94 tokens; SKILL.md has 545 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~94

When it runs · the whole SKILL.md, loaded when a task matches

~1.4k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~2.4k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from ukanwat/overtime at commit eac84e0, republished under its Apache-2.0 licence (© ukanwat). 545 words, ~1,449 tokens.

name

unreal-behavior-trees

description

Build NPC AI in Unreal Engine 5 with Behavior Trees and Blackboards: composites (Selector/Sequence), tasks, decorators, services, and running the tree from an AIController. Use when creating enemy/NPC AI, BT_/BB_ assets, custom BTTask or BTService nodes, or when the user mentions Behavior Tree, Blackboard, AIController, BTTask, decorator, or service.

compatibility

Unreal Engine 5.4+ (AIModule; Behavior Tree + Blackboard; NavMesh for movement)

license

Apache-2.0

metadata.engine

unreal

metadata.category

unreal

metadata.difficulty

advanced

void AEnemyAIController::OnPossess(APawn* InPawn)
{
    Super::OnPossess(InPawn);
    if (BehaviorTree)                 // UPROPERTY(EditAnywhere) TObjectPtr<UBehaviorTree>
        RunBehaviorTree(BehaviorTree); // initializes & uses the Blackboard the BT references
}

ROOT
└── Selector (try combat, else investigate, else patrol)
    ├── Sequence            [Decorator: Blackboard 'TargetActor' Is Set, Observer Aborts: Both]
    │     ├── Task: MoveTo (TargetActor)          // latent: returns InProgress then Succeeded
    │     └── Task: Attack
    ├── Sequence            [Decorator: 'LastKnownLocation' Is Set]
    │     ├── Task: MoveTo (LastKnownLocation)
    │     └── Task: Wait (3s) + clear key
    └── Task: Patrol (BTTask_FindPatrolPoint -> MoveTo)

void AEnemyAIController::SetTarget(AActor* Target)
{
    if (UBlackboardComponent* BB = GetBlackboardComponent())
        BB->SetValueAsObject(TEXT("TargetActor"), Target);   // key name must match the BB asset
}
// Clear with BB->ClearValue(TEXT("TargetActor")); to drop back to a lower-priority branch.

© ukanwat, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 1 other file (references) in .claude/skills/unreal-behavior-trees of ukanwat/overtime.

• SKILL.md
• references/custom-bttask.md

Open the folder on GitHubat commit eac84e0

Used in 1 other repository

We found 1 copy of this SKILL.md (exact, near-identical or edited) in other folders, from 1 other GitHub owner. This page covers the copy in ukanwat/overtime, which our catalogue first saw on October 7, 2026.

• gamedev-skills/awesome-gamedev-agent-skillsskills/unreal/unreal-behavior-trees