diff --git a/wasm/dist-repl/python/lumbda-py.js b/wasm/dist-repl/python/lumbda-py.js
index c716882..609cefc 100644
--- a/wasm/dist-repl/python/lumbda-py.js
+++ b/wasm/dist-repl/python/lumbda-py.js
@@ -2,7 +2,9 @@
 // Python tier loader — Pyodide (CPython-in-WASM) hosting lumbda.py.
 //
 // ES module form so it works in both window and Web Worker contexts.
-// Exports createPythonTier() -> Promise<{ evalLisp(src) -> Promise<string> }>.
+// Exports createPythonTier() -> Promise<{ evalLisp(src) -> Promise<string>,
+//                                          setBendUrl(url) -> void,
+//                                          heapStats() -> {used,total} }>.
 
 const PYODIDE_VERSION = "0.27.2";
 const PYODIDE_INDEX_URL = `https://cdn.jsdelivr.net/pyodide/v${PYODIDE_VERSION}/full/`;
@@ -22,6 +24,25 @@ async function _bootstrap() {
     pyodide.FS.writeFile("/home/pyodide/lumbda.py", lumbdaSrc);
     pyodide.FS.writeFile("/home/pyodide/stdlib.lsp", stdlibSrc);
 
+    // bend dispatch closure. Browser can't open raw TCP, so we POST
+    // the S-expression payload to the configured worker URL and read
+    // the response text back. Sync XHR is the only sync HTTP available
+    // in a Web Worker; perfect for the blocking eval model lumbda
+    // primitives expect.
+    const refs = { bendUrl: null };
+    globalThis._lumbdaPyBendCall = (payload) => {
+        if (!refs.bendUrl) return "no bend URL configured";
+        try {
+            const xhr = new XMLHttpRequest();
+            xhr.open("POST", refs.bendUrl, false);  // sync
+            xhr.setRequestHeader("Content-Type", "text/plain; charset=utf-8");
+            xhr.send(payload);
+            return xhr.responseText || "";
+        } catch (e) {
+            return `bend error: ${e.message || String(e)}`;
+        }
+    };
+
     await pyodide.runPythonAsync(`
 import sys, io
 sys.path.insert(0, "/home/pyodide")
@@ -30,6 +51,18 @@ _env = lumbda.make_global_env()
 for _e in lumbda.read_all(lumbda.PRELUDE):
     lumbda.leval(_e, _env)
 
+# bend!-call primitive — bridges to JS XHR via globalThis._lumbdaPyBendCall.
+# Argument: a string payload (the S-expression text). Returns response text.
+from js import _lumbdaPyBendCall as _js_bend_call
+def _bend_call_prim(args, env):
+    if not args:
+        return ""
+    payload = args[0]
+    if not isinstance(payload, str):
+        payload = lumbda.show(payload)
+    return str(_js_bend_call(payload))
+_env.define(lumbda.S('bend!-call'), _bend_call_prim)
+
 def _lumbda_eval(src):
     buf = io.StringIO()
     old = sys.stdout
@@ -56,6 +89,7 @@ def _lumbda_eval(src):
             pyodide.globals.set("_src_in", src);
             return await pyodide.runPythonAsync("_lumbda_eval(_src_in)");
         },
+        setBendUrl(url) { refs.bendUrl = url || null; },
         heapStats() {
             // Pyodide's runtime memory is the Emscripten linear memory.
             // CPython's GC reclaims behind the scenes, so this number
diff --git a/wasm/python/lumbda-py.js b/wasm/python/lumbda-py.js
index c716882..609cefc 100644
--- a/wasm/python/lumbda-py.js
+++ b/wasm/python/lumbda-py.js
@@ -2,7 +2,9 @@
 // Python tier loader — Pyodide (CPython-in-WASM) hosting lumbda.py.
 //
 // ES module form so it works in both window and Web Worker contexts.
-// Exports createPythonTier() -> Promise<{ evalLisp(src) -> Promise<string> }>.
+// Exports createPythonTier() -> Promise<{ evalLisp(src) -> Promise<string>,
+//                                          setBendUrl(url) -> void,
+//                                          heapStats() -> {used,total} }>.
 
 const PYODIDE_VERSION = "0.27.2";
 const PYODIDE_INDEX_URL = `https://cdn.jsdelivr.net/pyodide/v${PYODIDE_VERSION}/full/`;
@@ -22,6 +24,25 @@ async function _bootstrap() {
     pyodide.FS.writeFile("/home/pyodide/lumbda.py", lumbdaSrc);
     pyodide.FS.writeFile("/home/pyodide/stdlib.lsp", stdlibSrc);
 
+    // bend dispatch closure. Browser can't open raw TCP, so we POST
+    // the S-expression payload to the configured worker URL and read
+    // the response text back. Sync XHR is the only sync HTTP available
+    // in a Web Worker; perfect for the blocking eval model lumbda
+    // primitives expect.
+    const refs = { bendUrl: null };
+    globalThis._lumbdaPyBendCall = (payload) => {
+        if (!refs.bendUrl) return "no bend URL configured";
+        try {
+            const xhr = new XMLHttpRequest();
+            xhr.open("POST", refs.bendUrl, false);  // sync
+            xhr.setRequestHeader("Content-Type", "text/plain; charset=utf-8");
+            xhr.send(payload);
+            return xhr.responseText || "";
+        } catch (e) {
+            return `bend error: ${e.message || String(e)}`;
+        }
+    };
+
     await pyodide.runPythonAsync(`
 import sys, io
 sys.path.insert(0, "/home/pyodide")
@@ -30,6 +51,18 @@ _env = lumbda.make_global_env()
 for _e in lumbda.read_all(lumbda.PRELUDE):
     lumbda.leval(_e, _env)
 
+# bend!-call primitive — bridges to JS XHR via globalThis._lumbdaPyBendCall.
+# Argument: a string payload (the S-expression text). Returns response text.
+from js import _lumbdaPyBendCall as _js_bend_call
+def _bend_call_prim(args, env):
+    if not args:
+        return ""
+    payload = args[0]
+    if not isinstance(payload, str):
+        payload = lumbda.show(payload)
+    return str(_js_bend_call(payload))
+_env.define(lumbda.S('bend!-call'), _bend_call_prim)
+
 def _lumbda_eval(src):
     buf = io.StringIO()
     old = sys.stdout
@@ -56,6 +89,7 @@ def _lumbda_eval(src):
             pyodide.globals.set("_src_in", src);
             return await pyodide.runPythonAsync("_lumbda_eval(_src_in)");
         },
+        setBendUrl(url) { refs.bendUrl = url || null; },
         heapStats() {
             // Pyodide's runtime memory is the Emscripten linear memory.
             // CPython's GC reclaims behind the scenes, so this number
diff --git a/www/playground/python/lumbda-py.js b/www/playground/python/lumbda-py.js
index c716882..609cefc 100644
--- a/www/playground/python/lumbda-py.js
+++ b/www/playground/python/lumbda-py.js
@@ -2,7 +2,9 @@
 // Python tier loader — Pyodide (CPython-in-WASM) hosting lumbda.py.
 //
 // ES module form so it works in both window and Web Worker contexts.
-// Exports createPythonTier() -> Promise<{ evalLisp(src) -> Promise<string> }>.
+// Exports createPythonTier() -> Promise<{ evalLisp(src) -> Promise<string>,
+//                                          setBendUrl(url) -> void,
+//                                          heapStats() -> {used,total} }>.
 
 const PYODIDE_VERSION = "0.27.2";
 const PYODIDE_INDEX_URL = `https://cdn.jsdelivr.net/pyodide/v${PYODIDE_VERSION}/full/`;
@@ -22,6 +24,25 @@ async function _bootstrap() {
     pyodide.FS.writeFile("/home/pyodide/lumbda.py", lumbdaSrc);
     pyodide.FS.writeFile("/home/pyodide/stdlib.lsp", stdlibSrc);
 
+    // bend dispatch closure. Browser can't open raw TCP, so we POST
+    // the S-expression payload to the configured worker URL and read
+    // the response text back. Sync XHR is the only sync HTTP available
+    // in a Web Worker; perfect for the blocking eval model lumbda
+    // primitives expect.
+    const refs = { bendUrl: null };
+    globalThis._lumbdaPyBendCall = (payload) => {
+        if (!refs.bendUrl) return "no bend URL configured";
+        try {
+            const xhr = new XMLHttpRequest();
+            xhr.open("POST", refs.bendUrl, false);  // sync
+            xhr.setRequestHeader("Content-Type", "text/plain; charset=utf-8");
+            xhr.send(payload);
+            return xhr.responseText || "";
+        } catch (e) {
+            return `bend error: ${e.message || String(e)}`;
+        }
+    };
+
     await pyodide.runPythonAsync(`
 import sys, io
 sys.path.insert(0, "/home/pyodide")
@@ -30,6 +51,18 @@ _env = lumbda.make_global_env()
 for _e in lumbda.read_all(lumbda.PRELUDE):
     lumbda.leval(_e, _env)
 
+# bend!-call primitive — bridges to JS XHR via globalThis._lumbdaPyBendCall.
+# Argument: a string payload (the S-expression text). Returns response text.
+from js import _lumbdaPyBendCall as _js_bend_call
+def _bend_call_prim(args, env):
+    if not args:
+        return ""
+    payload = args[0]
+    if not isinstance(payload, str):
+        payload = lumbda.show(payload)
+    return str(_js_bend_call(payload))
+_env.define(lumbda.S('bend!-call'), _bend_call_prim)
+
 def _lumbda_eval(src):
     buf = io.StringIO()
     old = sys.stdout
@@ -56,6 +89,7 @@ def _lumbda_eval(src):
             pyodide.globals.set("_src_in", src);
             return await pyodide.runPythonAsync("_lumbda_eval(_src_in)");
         },
+        setBendUrl(url) { refs.bendUrl = url || null; },
         heapStats() {
             // Pyodide's runtime memory is the Emscripten linear memory.
             // CPython's GC reclaims behind the scenes, so this number
diff --git a/www/repl/python/lumbda-py.js b/www/repl/python/lumbda-py.js
index c716882..609cefc 100644
--- a/www/repl/python/lumbda-py.js
+++ b/www/repl/python/lumbda-py.js
@@ -2,7 +2,9 @@
 // Python tier loader — Pyodide (CPython-in-WASM) hosting lumbda.py.
 //
 // ES module form so it works in both window and Web Worker contexts.
-// Exports createPythonTier() -> Promise<{ evalLisp(src) -> Promise<string> }>.
+// Exports createPythonTier() -> Promise<{ evalLisp(src) -> Promise<string>,
+//                                          setBendUrl(url) -> void,
+//                                          heapStats() -> {used,total} }>.
 
 const PYODIDE_VERSION = "0.27.2";
 const PYODIDE_INDEX_URL = `https://cdn.jsdelivr.net/pyodide/v${PYODIDE_VERSION}/full/`;
@@ -22,6 +24,25 @@ async function _bootstrap() {
     pyodide.FS.writeFile("/home/pyodide/lumbda.py", lumbdaSrc);
     pyodide.FS.writeFile("/home/pyodide/stdlib.lsp", stdlibSrc);
 
+    // bend dispatch closure. Browser can't open raw TCP, so we POST
+    // the S-expression payload to the configured worker URL and read
+    // the response text back. Sync XHR is the only sync HTTP available
+    // in a Web Worker; perfect for the blocking eval model lumbda
+    // primitives expect.
+    const refs = { bendUrl: null };
+    globalThis._lumbdaPyBendCall = (payload) => {
+        if (!refs.bendUrl) return "no bend URL configured";
+        try {
+            const xhr = new XMLHttpRequest();
+            xhr.open("POST", refs.bendUrl, false);  // sync
+            xhr.setRequestHeader("Content-Type", "text/plain; charset=utf-8");
+            xhr.send(payload);
+            return xhr.responseText || "";
+        } catch (e) {
+            return `bend error: ${e.message || String(e)}`;
+        }
+    };
+
     await pyodide.runPythonAsync(`
 import sys, io
 sys.path.insert(0, "/home/pyodide")
@@ -30,6 +51,18 @@ _env = lumbda.make_global_env()
 for _e in lumbda.read_all(lumbda.PRELUDE):
     lumbda.leval(_e, _env)
 
+# bend!-call primitive — bridges to JS XHR via globalThis._lumbdaPyBendCall.
+# Argument: a string payload (the S-expression text). Returns response text.
+from js import _lumbdaPyBendCall as _js_bend_call
+def _bend_call_prim(args, env):
+    if not args:
+        return ""
+    payload = args[0]
+    if not isinstance(payload, str):
+        payload = lumbda.show(payload)
+    return str(_js_bend_call(payload))
+_env.define(lumbda.S('bend!-call'), _bend_call_prim)
+
 def _lumbda_eval(src):
     buf = io.StringIO()
     old = sys.stdout
@@ -56,6 +89,7 @@ def _lumbda_eval(src):
             pyodide.globals.set("_src_in", src);
             return await pyodide.runPythonAsync("_lumbda_eval(_src_in)");
         },
+        setBendUrl(url) { refs.bendUrl = url || null; },
         heapStats() {
             // Pyodide's runtime memory is the Emscripten linear memory.
             // CPython's GC reclaims behind the scenes, so this number