diff --git a/shared/static/scripts/sx-browser.js b/shared/static/scripts/sx-browser.js
index 04172ec9..b760b601 100644
--- a/shared/static/scripts/sx-browser.js
+++ b/shared/static/scripts/sx-browser.js
@@ -14,7 +14,7 @@
   // =========================================================================
 
   var NIL = Object.freeze({ _nil: true, toString: function() { return "nil"; } });
-  var SX_VERSION = "2026-03-14T10:16:03Z";
+  var SX_VERSION = "2026-03-14T10:27:39Z";
 
   function isNil(x) { return x === NIL || x === null || x === undefined; }
   function isSxTruthy(x) { return x !== false && !isNil(x); }
@@ -218,17 +218,6 @@
     return new Island(name, params, hasChildren, body, merge(env));
   }
 
-  // invoke — call any callable (native fn or SX lambda) with args.
-  // Transpiled code emits direct calls f(args) which fail on SX lambdas
-  // from runtime-evaluated island bodies. invoke dispatches correctly.
-  function invoke() {
-    var f = arguments[0];
-    var args = Array.prototype.slice.call(arguments, 1);
-    if (isLambda(f)) return trampoline(callLambda(f, args, lambdaClosure(f)));
-    if (typeof f === 'function') return f.apply(null, args);
-    return NIL;
-  }
-
   // JSON / dict helpers for island state serialization
   function jsonSerialize(obj) {
     return JSON.stringify(obj);
@@ -5192,8 +5181,8 @@ return (function() {
     // If lambda takes 0 params, call without event arg (convenience for on-click handlers)
     var wrapped = isLambda(handler)
       ? (lambdaParams(handler).length === 0
-        ? function(e) { try { invoke(handler); } catch(err) { console.error("[sx-ref] domListen handler error:", name, err); } }
-        : function(e) { try { invoke(handler, e); } catch(err) { console.error("[sx-ref] domListen handler error:", name, err); } })
+        ? function(e) { try { cekCall(handler, NIL); } catch(err) { console.error("[sx-ref] domListen handler error:", name, err); } }
+        : function(e) { try { cekCall(handler, [e]); } catch(err) { console.error("[sx-ref] domListen handler error:", name, err); } })
       : handler;
     if (name === "click") logInfo("domListen: click on <" + (el.tagName||"?").toLowerCase() + "> text=" + (el.textContent||"").substring(0,20) + " isLambda=" + isLambda(handler));
     el.addEventListener(name, wrapped);
@@ -6393,7 +6382,6 @@ return (function() {
   PRIMITIVES["stop-propagation"] = stopPropagation_;
   PRIMITIVES["error-message"] = errorMessage;
   PRIMITIVES["schedule-idle"] = scheduleIdle;
-  PRIMITIVES["invoke"] = invoke;
   PRIMITIVES["error"] = function(msg) { throw new Error(msg); };
   PRIMITIVES["filter"] = filter;
   // DOM primitives for sx-on:* handlers and data-init scripts
diff --git a/shared/sx/ref/platform_js.py b/shared/sx/ref/platform_js.py
index fc90b118..218418b8 100644
--- a/shared/sx/ref/platform_js.py
+++ b/shared/sx/ref/platform_js.py
@@ -1250,17 +1250,6 @@ PLATFORM_JS_PRE = '''
     return new Island(name, params, hasChildren, body, merge(env));
   }
 
-  // invoke — call any callable (native fn or SX lambda) with args.
-  // Transpiled code emits direct calls f(args) which fail on SX lambdas
-  // from runtime-evaluated island bodies. invoke dispatches correctly.
-  function invoke() {
-    var f = arguments[0];
-    var args = Array.prototype.slice.call(arguments, 1);
-    if (isLambda(f)) return trampoline(callLambda(f, args, lambdaClosure(f)));
-    if (typeof f === 'function') return f.apply(null, args);
-    return NIL;
-  }
-
   // JSON / dict helpers for island state serialization
   function jsonSerialize(obj) {
     return JSON.stringify(obj);
@@ -1809,8 +1798,8 @@ PLATFORM_DOM_JS = """
     // If lambda takes 0 params, call without event arg (convenience for on-click handlers)
     var wrapped = isLambda(handler)
       ? (lambdaParams(handler).length === 0
-        ? function(e) { try { invoke(handler); } catch(err) { console.error("[sx-ref] domListen handler error:", name, err); } }
-        : function(e) { try { invoke(handler, e); } catch(err) { console.error("[sx-ref] domListen handler error:", name, err); } })
+        ? function(e) { try { cekCall(handler, NIL); } catch(err) { console.error("[sx-ref] domListen handler error:", name, err); } }
+        : function(e) { try { cekCall(handler, [e]); } catch(err) { console.error("[sx-ref] domListen handler error:", name, err); } })
       : handler;
     if (name === "click") logInfo("domListen: click on <" + (el.tagName||"?").toLowerCase() + "> text=" + (el.textContent||"").substring(0,20) + " isLambda=" + isLambda(handler));
     el.addEventListener(name, wrapped);
@@ -3023,7 +3012,6 @@ def fixups_js(has_html, has_sx, has_dom, has_signals=False, has_deps=False, has_
   PRIMITIVES["stop-propagation"] = stopPropagation_;
   PRIMITIVES["error-message"] = errorMessage;
   PRIMITIVES["schedule-idle"] = scheduleIdle;
-  PRIMITIVES["invoke"] = invoke;
   PRIMITIVES["error"] = function(msg) { throw new Error(msg); };
   PRIMITIVES["filter"] = filter;
   // DOM primitives for sx-on:* handlers and data-init scripts
diff --git a/shared/sx/ref/platform_py.py b/shared/sx/ref/platform_py.py
index c0f1be1f..a84cf761 100644
--- a/shared/sx/ref/platform_py.py
+++ b/shared/sx/ref/platform_py.py
@@ -467,15 +467,6 @@ def is_identical(a, b):
 
 
 
-def invoke(f, *args):
-    """Call f with args — handles both native callables and SX lambdas.
-
-    In Python, all transpiled lambdas are natively callable, so this is
-    just a direct call. The JS host needs dispatch logic here because
-    SX lambdas from runtime-evaluated code are objects, not functions.
-    """
-    return f(*args)
-
 
 def json_serialize(obj):
     import json
diff --git a/shared/sx/ref/run_cek_reactive_tests.py b/shared/sx/ref/run_cek_reactive_tests.py
index 299e0229..73ef7251 100644
--- a/shared/sx/ref/run_cek_reactive_tests.py
+++ b/shared/sx/ref/run_cek_reactive_tests.py
@@ -6,6 +6,7 @@ import os, sys
 _HERE = os.path.dirname(os.path.abspath(__file__))
 _PROJECT = os.path.abspath(os.path.join(_HERE, "..", "..", ".."))
 sys.path.insert(0, _PROJECT)
+sys.setrecursionlimit(20000)
 
 from shared.sx.parser import parse_all
 from shared.sx.ref import sx_ref
@@ -138,8 +139,8 @@ env["env-merge"] = env_merge
 env["symbol-name"] = lambda s: s.name if isinstance(s, Symbol) else str(s)
 env["keyword-name"] = lambda k: k.name if isinstance(k, Keyword) else str(k)
 env["type-of"] = sx_ref.type_of
-env["primitive?"] = lambda n: n in sx_ref.PRIMITIVES
-env["get-primitive"] = lambda n: sx_ref.PRIMITIVES.get(n)
+env["primitive?"] = sx_ref.is_primitive
+env["get-primitive"] = sx_ref.get_primitive
 env["strip-prefix"] = lambda s, p: s[len(p):] if s.startswith(p) else s
 env["inspect"] = repr
 env["debug-log"] = lambda *args: None
@@ -201,16 +202,6 @@ env["call-thunk"] = lambda f, e: f() if callable(f) else trampoline(eval_expr([f
 env["dict-get"] = lambda d, k: d.get(k, NIL) if isinstance(d, dict) else NIL
 env["identical?"] = lambda a, b: a is b
 
-def _invoke(f, *args):
-    """Call f with args — handles both native callables and SX lambdas."""
-    if isinstance(f, Lambda):
-        return trampoline(sx_ref.call_lambda(f, list(args), env))
-    elif callable(f):
-        return f(*args)
-    return NIL
-
-env["invoke"] = _invoke
-
 # defhandler, defpage, defquery, defaction stubs
 for name in ["sf-defhandler", "sf-defpage", "sf-defquery", "sf-defaction"]:
     pyname = name.replace("-", "_")
diff --git a/shared/sx/ref/run_signal_tests.py b/shared/sx/ref/run_signal_tests.py
index 3e7e21bd..80f0ce74 100644
--- a/shared/sx/ref/run_signal_tests.py
+++ b/shared/sx/ref/run_signal_tests.py
@@ -1,7 +1,7 @@
 #!/usr/bin/env python3
 """Run test-signals.sx using the bootstrapped evaluator with signal primitives.
 
-Uses bootstrapped signal functions from sx_ref.py directly, patching invoke
+Uses bootstrapped signal functions from sx_ref.py directly, patching apply
 to handle SX lambdas from the interpreter (test expressions create lambdas
 that need evaluator dispatch).
 """
@@ -25,14 +25,9 @@ sx_ref.trampoline = trampoline
 # Build env with primitives
 env = make_env()
 
-# --- Patch invoke and apply BEFORE anything else ---
-# Test expressions create SX Lambdas that bootstrapped code calls via invoke/apply.
-# Patch the module-level functions so all bootstrapped functions see them.
-def _invoke(f, *args):
-    if isinstance(f, Lambda):
-        return trampoline(eval_expr([f] + list(args), env))
-    return f(*args)
-sx_ref.__dict__["invoke"] = _invoke
+# --- Patch apply BEFORE anything else ---
+# Test expressions create SX Lambdas that bootstrapped code calls via apply.
+# Patch the module-level function so all bootstrapped functions see it.
 
 # apply is used by swap! and other forms to call functions with arg lists
 def _apply(f, args):
@@ -124,7 +119,7 @@ env["effect"] = sx_ref.effect
 # Wrap it to work correctly in the test context.
 def _batch(thunk):
     sx_ref._batch_depth = getattr(sx_ref, '_batch_depth', 0) + 1
-    _invoke(thunk)
+    sx_ref.cek_call(thunk, None)
     sx_ref._batch_depth -= 1
     if sx_ref._batch_depth == 0:
         queue = list(sx_ref._batch_queue)
@@ -145,7 +140,6 @@ env["flush-subscribers"] = sx_ref.flush_subscribers
 env["dispose-computed"] = sx_ref.dispose_computed
 env["with-island-scope"] = sx_ref.with_island_scope
 env["register-in-scope"] = sx_ref.register_in_scope
-env["invoke"] = _invoke
 env["callable?"] = sx_ref.is_callable
 
 # Load test framework
diff --git a/shared/sx/ref/sx_ref.py b/shared/sx/ref/sx_ref.py
index 2a4a2b98..aad3ff52 100644
--- a/shared/sx/ref/sx_ref.py
+++ b/shared/sx/ref/sx_ref.py
@@ -426,15 +426,6 @@ def is_identical(a, b):
 
 
 
-def invoke(f, *args):
-    """Call f with args — handles both native callables and SX lambdas.
-
-    In Python, all transpiled lambdas are natively callable, so this is
-    just a direct call. The JS host needs dispatch logic here because
-    SX lambdas from runtime-evaluated code are objects, not functions.
-    """
-    return f(*args)
-
 
 def json_serialize(obj):
     import json
diff --git a/shared/sx/ref/test-cek-reactive.sx b/shared/sx/ref/test-cek-reactive.sx
index 456501c3..0669dcdb 100644
--- a/shared/sx/ref/test-cek-reactive.sx
+++ b/shared/sx/ref/test-cek-reactive.sx
@@ -152,3 +152,60 @@
       ;; Change signal — no update should fire
       (reset! s 999)
       (assert-equal 0 (len update-calls)))))
+
+
+;; --------------------------------------------------------------------------
+;; cek-call integration — computed/effect use cek-call dispatch
+;; --------------------------------------------------------------------------
+
+(defsuite "cek-call dispatch"
+  (deftest "cek-call invokes native function"
+    (let ((log (list)))
+      (cek-call (fn (x) (append! log x)) (list 42))
+      (assert-equal (list 42) log)))
+
+  (deftest "cek-call invokes zero-arg lambda"
+    (let ((result (cek-call (fn () (+ 1 2)) nil)))
+      (assert-equal 3 result)))
+
+  (deftest "cek-call with nil function returns nil"
+    (assert-nil (cek-call nil nil)))
+
+  (deftest "computed tracks deps via cek-call"
+    (let ((s (signal 10)))
+      (let ((c (computed (fn () (* 2 (deref s))))))
+        (assert-equal 20 (deref c))
+        (reset! s 5)
+        (assert-equal 10 (deref c)))))
+
+  (deftest "effect runs and re-runs via cek-call"
+    (let ((s (signal "a"))
+          (log (list)))
+      (effect (fn () (append! log (deref s))))
+      (assert-equal (list "a") log)
+      (reset! s "b")
+      (assert-equal (list "a" "b") log)))
+
+  (deftest "effect cleanup runs on re-trigger"
+    (let ((s (signal 0))
+          (log (list)))
+      (effect (fn ()
+        (let ((val (deref s)))
+          (append! log (str "run:" val))
+          ;; Return cleanup function
+          (fn () (append! log (str "clean:" val))))))
+      (assert-equal (list "run:0") log)
+      (reset! s 1)
+      (assert-equal (list "run:0" "clean:0" "run:1") log)))
+
+  (deftest "batch coalesces via cek-call"
+    (let ((s (signal 0))
+          (count (signal 0)))
+      (effect (fn () (do (deref s) (swap! count inc))))
+      (assert-equal 1 (deref count))
+      (batch (fn ()
+        (reset! s 1)
+        (reset! s 2)
+        (reset! s 3)))
+      ;; batch should coalesce — effect runs once, not three times
+      (assert-equal 2 (deref count)))))