improvement(feature-flags): fallback is the env secret key (keyof typeof env), resolved to a boolean

Author: TheodoreSpeaks

.claude/commands/add-feature-flag.md

@@ -37,12 +37,12 @@ Critically, **none of this is expressible in code** — gating (especially `admi
    const FEATURE_FLAGS = {
      '<flag-name>': {
        description: '<what this gates>',
-       fallback: () => env.<FLAG_SECRET>,
+       fallback: '<FLAG_SECRET>',
      },
    }
    ```
 
-   Add `<FLAG_SECRET>` to `apps/sim/lib/core/config/env.ts` (and the deployment's secret store). Do **not** add org/user/admin defaults here — that gating exists only in AppConfig. Adding the entry makes `<flag-name>` a valid `FeatureFlagName`.
+   `fallback` is the env/secret key (typed as `keyof typeof env`), so add `<FLAG_SECRET>` to `apps/sim/lib/core/config/env.ts` first (and the deployment's secret store) — it won't typecheck otherwise. Do **not** add org/user/admin defaults here — that gating exists only in AppConfig. Adding the entry makes `<flag-name>` a valid `FeatureFlagName`.
 
 2. **Gate the call site.** Call `isFeatureEnabled` with whatever ids you have — admin status is resolved internally, so callers never pass it:
 

.cursor/commands/add-feature-flag.md

@@ -32,12 +32,12 @@ Critically, **none of this is expressible in code** — gating (especially `admi
    const FEATURE_FLAGS = {
      '<flag-name>': {
        description: '<what this gates>',
-       fallback: () => env.<FLAG_SECRET>,
+       fallback: '<FLAG_SECRET>',
      },
    }
    ```
 
-   Add `<FLAG_SECRET>` to `apps/sim/lib/core/config/env.ts` (and the deployment's secret store). Do **not** add org/user/admin defaults here — that gating exists only in AppConfig. Adding the entry makes `<flag-name>` a valid `FeatureFlagName`.
+   `fallback` is the env/secret key (typed as `keyof typeof env`), so add `<FLAG_SECRET>` to `apps/sim/lib/core/config/env.ts` first (and the deployment's secret store) — it won't typecheck otherwise. Do **not** add org/user/admin defaults here — that gating exists only in AppConfig. Adding the entry makes `<flag-name>` a valid `FeatureFlagName`.
 
 2. **Gate the call site.** Call `isFeatureEnabled` with whatever ids you have — admin status is resolved internally, so callers never pass it:
 

apps/sim/lib/core/config/feature-flags.ts

@@ -58,14 +58,15 @@ export interface FeatureFlagContext {
  */
 interface FeatureFlagDefinition {
   description: string
-  fallback: () => string | boolean | number | undefined
+  /** Env/secret key consulted when AppConfig isn't the source of truth. Truthy ⇒ on. */
+  fallback: keyof typeof env
 }
 
 /** The single registry of known flags. To add a flag, add one entry here. */
 const FEATURE_FLAGS = {
   // 'new-canvas': {
   //   description: 'New canvas renderer',
-  //   fallback: () => env.NEW_CANVAS_ENABLED,
+  //   fallback: 'NEW_CANVAS_ENABLED',
   // },
 } satisfies Record<string, FeatureFlagDefinition>
 
@@ -81,7 +82,7 @@ function fallbackFlags(): FeatureFlagsConfig {
   for (const [name, def] of Object.entries(FEATURE_FLAGS) as Array<
     [string, FeatureFlagDefinition]
   >) {
-    flags[name] = { enabled: isTruthy(def.fallback()) }
+    flags[name] = { enabled: isTruthy(env[def.fallback]) }
   }
   return { flags }
 }