diff --git a/libs/common/src/tools/achievements/event-processor.ts b/libs/common/src/tools/achievements/event-processor.ts
index e69de29bb2d..b706bef2324 100644
--- a/libs/common/src/tools/achievements/event-processor.ts
+++ b/libs/common/src/tools/achievements/event-processor.ts
@@ -0,0 +1,57 @@
+import {
+  Observable,
+  OperatorFunction,
+  concatMap,
+  filter,
+  from,
+  map,
+  pipe,
+  withLatestFrom,
+} from "rxjs";
+
+import { EventFormat } from "../log/ecs-format";
+
+import { achievementMonitors$, achievementsLocal$, userActionIn$ } from "./inputs";
+import { AchievementFormat, AchievementWatch } from "./types";
+
+// the formal even processor
+function validate(
+  achievements$: Observable<AchievementWatch[]>,
+  status$: Observable<AchievementFormat[]>,
+): OperatorFunction<EventFormat, AchievementFormat> {
+  // compute list of active monitors
+  const monitors$ = achievements$.pipe(
+    withLatestFrom(achievementsLocal$),
+    filter(([monitors, local]) => {
+      // 🧩 TODO: filter out inactive monitors by reviewing local store
+      //          and interpreting triggers.
+      return true;
+    }),
+  );
+
+  // analyze the incoming event stream to identify achievements
+  const processor = pipe(
+    withLatestFrom(monitors$),
+    map(([action, monitors]) => {
+      // 🧩 TODO: transform list of monitors to the list of monitors triggered
+      //          by the incoming action
+      return [action, monitors];
+    }),
+    withLatestFrom(status$),
+    concatMap(([[action, monitors], status]) => {
+      // 🧩 TODO: execute each of the monitors feeding in its associated achievement
+      //          entry and the action that triggered the achievement.
+      return from([] as AchievementFormat[]);
+    }),
+  );
+
+  return processor;
+}
+
+// pre-wired achievement stream; this is the prototype's host, and
+//  in the full version is wired by the application
+const validatedAchievements$ = userActionIn$.pipe(
+  validate(achievementMonitors$, achievementsLocal$),
+);
+
+export { validate, validatedAchievements$ };
diff --git a/libs/common/src/tools/achievements/inputs.ts b/libs/common/src/tools/achievements/inputs.ts
index 2700e4c09af..b1b970c48b0 100644
--- a/libs/common/src/tools/achievements/inputs.ts
+++ b/libs/common/src/tools/achievements/inputs.ts
@@ -11,10 +11,10 @@ const replicationIn$ = new Subject<AchievementFormat>();
 const userActionIn$ = new Subject<EventFormat>();
 
 // what to look for (consumed by validator)
-const achievementMonitors$ = new Subject<AchievementWatch>();
+const achievementMonitors$ = new Subject<AchievementWatch[]>();
 
 // data stored in local state  (consumed by validator and achievement list)
-const achievementsLocal$ = new Subject<AchievementFormat>();
+const achievementsLocal$ = new Subject<AchievementFormat[]>();
 
 // metadata (consumed by achievement list)
 const achievementMetadata$ = new Subject<Achievement>();