fix structured call 1

wasm/llm-wasm.build.txt

@@ -1,4 +1,4 @@
 llama.cpp commit: f7591a6a01f9273de03331732bdc0b39721168be
 llama.cpp subject: sycl: add f16 support for SWIGLU_OAI (#30857)
 emcc: emcc (Emscripten gcc/clang-like replacement + linker emulating GNU ld) 7.0.0 (777e6e5db7b4990bcaeb1b9998ed642cc84e6629)
-built: 2026-11-09T14:39:26Z
+built: 2026-11-11T09:31:06Z

wasm/llm-wasm.wasm

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:fc70bfd506a4b21c107f6680e4c94a21daa5d7491bb64de0f07b3d143d8d954e
-size 7050007
+oid sha256:29b579b19aa063295a4aa494d2d981436685f97b8603b7ff047cf8b97830bd0b
+size 7141666

worker.js

@@ -428,15 +428,23 @@ async function run(opts) {
     }
 
     // structured output: only when the page chose a schema. The tool-call path
-    // sends neither, so it runs exactly as before.
-    if (!grammar && json_schema && json_schema.trim()) {
+    // sends neither, so it runs exactly as before. `grammar` above is a const
+    // destructured binding, so the schema's result needs its own local.
+    let grammarText = grammar;
+    if (!grammarText && json_schema && json_schema.trim()) {
+        if (typeof module._llmjs_grammar_from_schema !== "function") {
+            fail(new Error("this module build has no JSON schema support; the threaded build "
+                           + "(needs COOP/COEP) has it, or paste a GBNF grammar instead"));
+            return;
+        }
         const asGrammar = module.ccall("llmjs_grammar_from_schema", "string",
                                        ["string"], [json_schema]);
         if (!asGrammar) {
-            fail(new Error(`could not use the JSON schema: ${module.UTF8ToString(module._llmjs_last_error())}`));
+            const why = module.UTF8ToString(module._llmjs_last_error());
+            fail(new Error(`could not use the JSON schema: ${why}`));
             return;
         }
-        grammar = asGrammar;
+        grammarText = asGrammar;
     }
 
     if (createContext(context_size || currentNctx) < 0) {
@@ -465,7 +473,7 @@ async function run(opts) {
             ["string", "string", "string", "string", "number", "number", "number",
              "number", "number", "number", "number", "string"],
             [JSON.stringify(list), tools || "[]", chat_template_source, template_kwargs || "{}",
-             max_token_len, temp, top_k, top_p, repeat_penalty, repeat_last_n, seed, grammar],
+             max_token_len, temp, top_k, top_p, repeat_penalty, repeat_last_n, seed, grammarText],
         );
     } else {
         rc = module.ccall(
@@ -474,7 +482,7 @@ async function run(opts) {
             ["string", "number", "number", "number", "number", "number",
              "number", "number", "string"],
             [prompt, max_token_len, temp, top_k, top_p, repeat_penalty,
-             repeat_last_n, seed, grammar],
+             repeat_last_n, seed, grammarText],
         );
     }
     if (rc < 0) {