stemstudio-eventbus

name	stemstudio-eventbus
description	EventBus guidance for behavior-to-behavior messaging in Studio 3D. Use when behaviors need decoupled communication, topic design, or event lifecycle cleanup.

StemStudio EventBus

Use this skill when behaviors need publish/subscribe communication.

This is primarily a behavior-authoring skill, not a scene-command skill.

Use This Skill For

• topic naming
• sending events between behaviors
• subscribing and unsubscribing safely
• choosing event-driven coordination over direct references

Critical Pattern

Always:

• subscribe in the correct startup phase
• store subscription tokens
• unsubscribe in cleanup
• keep payloads small and explicit

Use EventBus when systems should be decoupled. Do not use it as a replacement for plain local state.

Typical Uses

• player/enemy communication
• game-state broadcasts
• UI-triggered behavior reactions
• collectible and trigger notifications
• cross-object coordination without tight references

When To Read More

• Need publish/subscribe API behavior or topic conventions: ~/.claude/stemstudio-docs/event-system.md
• Need exact registered topics or constants: ~/.claude/stemstudio-types/stem-events-registry.json
• Need exact type declarations: ~/.claude/stemstudio-types/stem-types.d.ts

If you are writing the behavior itself, also load stemstudio-behaviors.

Common Mistakes

• forgetting to unsubscribe in cleanup
• inventing event names when a registered topic already exists
• sending oversized payloads
• using EventBus where direct local logic would be simpler

Verification

Verify by:

• checking sender and receiver topic names match
• confirming subscription lifecycle cleanup
• logging or tracing event flow only as narrowly as needed for debugging

See Also

• stemstudio-behaviors
• stemstudio-game-engine