diff --git a/wasm/c/lumbda-c.loader.js b/wasm/c/lumbda-c.loader.js
index 1e2e8e2..bfde8d3 100644
--- a/wasm/c/lumbda-c.loader.js
+++ b/wasm/c/lumbda-c.loader.js
@@ -30,13 +30,19 @@ async function _bootstrap() {
     let outBuf = [];
     let errBuf = [];
     let currentOnChunk = null;
+    // Temporary debug — log every Module.print invocation so we can
+    // see exactly what Emscripten passes us (with/without trailing
+    // newline). Remove once the streaming-newline bug is resolved.
+    const DEBUG_STREAM = true;
     const module = await createLumbdaC({
         locateFile: (p) => wasmDir + p,
         print: (line) => {
+            if (DEBUG_STREAM) console.log("[c-tier print]", JSON.stringify(line));
             outBuf.push(line);
             if (currentOnChunk) currentOnChunk(line + "\n");
         },
         printErr: (line) => {
+            if (DEBUG_STREAM) console.log("[c-tier printErr]", JSON.stringify(line));
             errBuf.push(line);
             if (currentOnChunk) currentOnChunk(line + "\n");
         },
diff --git a/wasm/dist-repl/c/lumbda-c.loader.js b/wasm/dist-repl/c/lumbda-c.loader.js
index 1e2e8e2..bfde8d3 100644
--- a/wasm/dist-repl/c/lumbda-c.loader.js
+++ b/wasm/dist-repl/c/lumbda-c.loader.js
@@ -30,13 +30,19 @@ async function _bootstrap() {
     let outBuf = [];
     let errBuf = [];
     let currentOnChunk = null;
+    // Temporary debug — log every Module.print invocation so we can
+    // see exactly what Emscripten passes us (with/without trailing
+    // newline). Remove once the streaming-newline bug is resolved.
+    const DEBUG_STREAM = true;
     const module = await createLumbdaC({
         locateFile: (p) => wasmDir + p,
         print: (line) => {
+            if (DEBUG_STREAM) console.log("[c-tier print]", JSON.stringify(line));
             outBuf.push(line);
             if (currentOnChunk) currentOnChunk(line + "\n");
         },
         printErr: (line) => {
+            if (DEBUG_STREAM) console.log("[c-tier printErr]", JSON.stringify(line));
             errBuf.push(line);
             if (currentOnChunk) currentOnChunk(line + "\n");
         },
diff --git a/www/playground/c/lumbda-c.loader.js b/www/playground/c/lumbda-c.loader.js
index 1e2e8e2..bfde8d3 100644
--- a/www/playground/c/lumbda-c.loader.js
+++ b/www/playground/c/lumbda-c.loader.js
@@ -30,13 +30,19 @@ async function _bootstrap() {
     let outBuf = [];
     let errBuf = [];
     let currentOnChunk = null;
+    // Temporary debug — log every Module.print invocation so we can
+    // see exactly what Emscripten passes us (with/without trailing
+    // newline). Remove once the streaming-newline bug is resolved.
+    const DEBUG_STREAM = true;
     const module = await createLumbdaC({
         locateFile: (p) => wasmDir + p,
         print: (line) => {
+            if (DEBUG_STREAM) console.log("[c-tier print]", JSON.stringify(line));
             outBuf.push(line);
             if (currentOnChunk) currentOnChunk(line + "\n");
         },
         printErr: (line) => {
+            if (DEBUG_STREAM) console.log("[c-tier printErr]", JSON.stringify(line));
             errBuf.push(line);
             if (currentOnChunk) currentOnChunk(line + "\n");
         },
diff --git a/www/repl/c/lumbda-c.loader.js b/www/repl/c/lumbda-c.loader.js
index 1e2e8e2..bfde8d3 100644
--- a/www/repl/c/lumbda-c.loader.js
+++ b/www/repl/c/lumbda-c.loader.js
@@ -30,13 +30,19 @@ async function _bootstrap() {
     let outBuf = [];
     let errBuf = [];
     let currentOnChunk = null;
+    // Temporary debug — log every Module.print invocation so we can
+    // see exactly what Emscripten passes us (with/without trailing
+    // newline). Remove once the streaming-newline bug is resolved.
+    const DEBUG_STREAM = true;
     const module = await createLumbdaC({
         locateFile: (p) => wasmDir + p,
         print: (line) => {
+            if (DEBUG_STREAM) console.log("[c-tier print]", JSON.stringify(line));
             outBuf.push(line);
             if (currentOnChunk) currentOnChunk(line + "\n");
         },
         printErr: (line) => {
+            if (DEBUG_STREAM) console.log("[c-tier printErr]", JSON.stringify(line));
             errBuf.push(line);
             if (currentOnChunk) currentOnChunk(line + "\n");
         },