diff --git a/packages/core/src/core.types.ts b/packages/core/src/core.types.ts
index 36f3c2dc7..929fef6de 100644
--- a/packages/core/src/core.types.ts
+++ b/packages/core/src/core.types.ts
@@ -88,6 +88,20 @@ export interface TimelineCompositionElement extends TimelineElementBase {
 // Composition Variable Types
 export type CompositionVariableType = "string" | "number" | "color" | "boolean" | "enum";
 
+/**
+ * Runtime list of every valid `CompositionVariableType`. Use this anywhere
+ * a Set/array of valid type strings is needed (lint rules, validators).
+ * The `satisfies` guard turns adding a new variant to the union without
+ * also adding it here into a compile error.
+ */
+export const COMPOSITION_VARIABLE_TYPES = [
+  "string",
+  "number",
+  "color",
+  "boolean",
+  "enum",
+] as const satisfies readonly CompositionVariableType[];
+
 export interface CompositionVariableBase {
   id: string;
   type: CompositionVariableType;
diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index 4c66cef33..8a0906552 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -38,6 +38,7 @@ export {
   CANVAS_DIMENSIONS,
   TIMELINE_COLORS,
   DEFAULT_DURATIONS,
+  COMPOSITION_VARIABLE_TYPES,
   isTextElement,
   isMediaElement,
   isCompositionElement,
diff --git a/packages/core/src/lint/rules/composition.ts b/packages/core/src/lint/rules/composition.ts
index a7909d5b9..0f02b1a4a 100644
--- a/packages/core/src/lint/rules/composition.ts
+++ b/packages/core/src/lint/rules/composition.ts
@@ -1,5 +1,6 @@
 import type { LintContext, HyperframeLintFinding } from "../context";
 import { findHtmlTag, readAttr, readJsonAttr, truncateSnippet } from "../utils";
+import { COMPOSITION_VARIABLE_TYPES } from "../../core.types";
 
 // Agent guidance thresholds: warning-only nudges for files/tracks that become hard
 // to inspect and revise reliably in a single composition.
@@ -475,7 +476,7 @@ export const compositionRules: Array<(ctx: LintContext) => HyperframeLintFinding
     }
 
     const findings: HyperframeLintFinding[] = [];
-    const knownTypes = new Set(["string", "number", "color", "boolean", "enum"]);
+    const knownTypes = new Set<string>(COMPOSITION_VARIABLE_TYPES);
     for (let i = 0; i < parsed.length; i += 1) {
       const entry = parsed[i];
       if (!entry || typeof entry !== "object" || Array.isArray(entry)) {