diff --git a/hosts/ocaml/bin/sx_server.ml b/hosts/ocaml/bin/sx_server.ml
index daa4b4b..c904fec 100644
--- a/hosts/ocaml/bin/sx_server.ml
+++ b/hosts/ocaml/bin/sx_server.ml
@@ -413,6 +413,18 @@ let make_server_env () =
   bind "dom-get-data" (fun _args -> Nil);
   bind "event-detail" (fun _args -> Nil);
   bind "promise-then" (fun _args -> Nil);
+  bind "thunk?" (fun args -> match args with [Thunk _] -> Bool true | _ -> Bool false);
+  bind "thunk-expr" (fun args -> match args with [v] -> thunk_expr v | _ -> Nil);
+  bind "thunk-env" (fun args -> match args with [v] -> thunk_env v | _ -> Nil);
+  bind "schedule-idle" (fun _args -> Nil);
+  bind "dom-query" (fun _args -> Nil);
+  bind "dom-query-all" (fun _args -> List []);
+  bind "dom-set-prop" (fun _args -> Nil);
+  bind "dom-get-attr" (fun _args -> Nil);
+  bind "dom-set-attr" (fun _args -> Nil);
+  bind "dom-text-content" (fun _args -> String "");
+  bind "dom-set-text-content" (fun _args -> Nil);
+  bind "dom-body" (fun _args -> Nil);
 
   (* Raw HTML — platform primitives for adapter-html.sx *)
   bind "make-raw-html" (fun args ->
@@ -503,7 +515,12 @@ let make_server_env () =
     | _ -> raise (Eval_error "eval-expr: expected (expr env?)"));
   bind "trampoline" (fun args ->
     match args with
-    | [v] -> v  (* CEK never produces thunks *)
+    | [v] ->
+      (* sf-letrec returns thunks — resolve them *)
+      let rec resolve v = match v with
+        | Thunk (expr, env) -> resolve (Sx_ref.eval_expr expr (Env env))
+        | _ -> v
+      in resolve v
     | _ -> raise (Eval_error "trampoline: expected 1 arg"));
   bind "call-lambda" (fun args ->
     match args with
diff --git a/shared/static/scripts/sx-browser.js b/shared/static/scripts/sx-browser.js
index 6297351..7fe53e3 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 = "2026-03-23T13:21:57Z";
+  var SX_VERSION = "2026-03-23T15:29:13Z";
 
   function isNil(x) { return x === NIL || x === null || x === undefined; }
   function isSxTruthy(x) { return x !== false && !isNil(x); }
@@ -2456,11 +2456,11 @@ PRIMITIVES["serialize"] = serialize;
 
   // render-to-html
   var renderToHtml = function(expr, env) { setRenderActiveB(true);
-return (function() { var _m = typeOf(expr); if (_m == "nil") return ""; if (_m == "string") return escapeHtml(expr); if (_m == "number") return (String(expr)); if (_m == "boolean") return (isSxTruthy(expr) ? "true" : "false"); if (_m == "list") return (isSxTruthy(isEmpty(expr)) ? "" : renderListToHtml(expr, env)); if (_m == "symbol") return renderValueToHtml(trampoline(evalExpr(expr, env)), env); if (_m == "keyword") return escapeHtml(keywordName(expr)); if (_m == "raw-html") return rawHtmlContent(expr); if (_m == "spread") return (sxEmit("element-attrs", spreadAttrs(expr)), ""); return renderValueToHtml(trampoline(evalExpr(expr, env)), env); })(); };
+return (function() { var _m = typeOf(expr); if (_m == "nil") return ""; if (_m == "string") return escapeHtml(expr); if (_m == "number") return (String(expr)); if (_m == "boolean") return (isSxTruthy(expr) ? "true" : "false"); if (_m == "list") return (isSxTruthy(isEmpty(expr)) ? "" : renderListToHtml(expr, env)); if (_m == "symbol") return renderValueToHtml(trampoline(evalExpr(expr, env)), env); if (_m == "keyword") return escapeHtml(keywordName(expr)); if (_m == "raw-html") return rawHtmlContent(expr); if (_m == "spread") return (sxEmit("element-attrs", spreadAttrs(expr)), ""); if (_m == "thunk") return renderToHtml(thunkExpr(expr), thunkEnv(expr)); return renderValueToHtml(trampoline(evalExpr(expr, env)), env); })(); };
 PRIMITIVES["render-to-html"] = renderToHtml;
 
   // render-value-to-html
-  var renderValueToHtml = function(val, env) { return (function() { var _m = typeOf(val); if (_m == "nil") return ""; if (_m == "string") return escapeHtml(val); if (_m == "number") return (String(val)); if (_m == "boolean") return (isSxTruthy(val) ? "true" : "false"); if (_m == "list") return renderListToHtml(val, env); if (_m == "raw-html") return rawHtmlContent(val); if (_m == "spread") return (sxEmit("element-attrs", spreadAttrs(val)), ""); return escapeHtml((String(val))); })(); };
+  var renderValueToHtml = function(val, env) { return (function() { var _m = typeOf(val); if (_m == "nil") return ""; if (_m == "string") return escapeHtml(val); if (_m == "number") return (String(val)); if (_m == "boolean") return (isSxTruthy(val) ? "true" : "false"); if (_m == "list") return renderListToHtml(val, env); if (_m == "raw-html") return rawHtmlContent(val); if (_m == "spread") return (sxEmit("element-attrs", spreadAttrs(val)), ""); if (_m == "thunk") return renderToHtml(thunkExpr(val), thunkEnv(val)); return escapeHtml((String(val))); })(); };
 PRIMITIVES["render-value-to-html"] = renderValueToHtml;
 
   // RENDER_HTML_FORMS
diff --git a/shared/sx/ocaml_bridge.py b/shared/sx/ocaml_bridge.py
index 45eb572..bbc13d3 100644
--- a/shared/sx/ocaml_bridge.py
+++ b/shared/sx/ocaml_bridge.py
@@ -439,6 +439,15 @@ class OcamlBridge:
                         skipped += 1
                         _logger.warning("OCaml load skipped %s: %s",
                                         filepath, e)
+                # SSR overrides: effect is a no-op on the server (prevents
+                # reactive loops during island SSR — effects are DOM side-effects)
+                try:
+                    noop_dispose = '(fn () nil)'
+                    await self._send(f'(load-source "(define effect (fn (f) {noop_dispose}))")')
+                    await self._read_until_ok(ctx=None)
+                except OcamlBridgeError:
+                    pass
+
                 # Register JIT hook — lambdas compile on first call
                 try:
                     await self._send('(vm-compile-adapter)')
diff --git a/web/adapter-html.sx b/web/adapter-html.sx
index 156b783..29125dd 100644
--- a/web/adapter-html.sx
+++ b/web/adapter-html.sx
@@ -32,6 +32,8 @@
       "raw-html" (raw-html-content expr)
       ;; Spread — emit attrs to nearest element provider
       "spread"  (do (emit! "element-attrs" (spread-attrs expr)) "")
+      ;; Thunk — unwrap and render the inner expression (from letrec TCO)
+      "thunk"   (render-to-html (thunk-expr expr) (thunk-env expr))
       ;; Everything else — evaluate first
       :else     (render-value-to-html (trampoline (eval-expr expr env)) env))))
 
@@ -45,6 +47,7 @@
       "list"    (render-list-to-html val env)
       "raw-html" (raw-html-content val)
       "spread"  (do (emit! "element-attrs" (spread-attrs val)) "")
+      "thunk"   (render-to-html (thunk-expr val) (thunk-env val))
       :else     (escape-html (str val)))))