diff --git a/package.json b/package.json
index e360941..159bbd2 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@uschuster/webapp-scaffold",
-  "version": "0.3.3",
+  "version": "0.3.4",
   "description": "Shared build scripts + Vite config factories for webapp-template-derived projects.",
   "type": "module",
   "bin": {
diff --git a/src/core-fetch.ts b/src/core-fetch.ts
index 3f6fd34..a165531 100644
--- a/src/core-fetch.ts
+++ b/src/core-fetch.ts
@@ -149,24 +149,25 @@ export function createCoreFetch(opts: CoreFetchOptions = {}): CoreFetch {
         }
 
         if (r.status === 401) opts.on401?.(req);
-        if (r.status === 409 && opts.on409) {
-            const body = await r.text();
-            const resolved = opts.on409(req, body);
-            if (resolved !== undefined) {
-                return wrap(resolved, r.status, r.headers) as T;
+        if (r.status === 409) {
+            const [text, json] = await readBody(r);
+            if (opts.on409) {
+                const resolved = opts.on409(req, text);
+                if (resolved !== undefined) {
+                    return wrap(resolved, r.status, r.headers) as T;
+                }
             }
-            // Fall through to error-formatting path below.
-            const bodyJson = safeJson(body);
-            const msg = opts.formatError?.(req, r, body, bodyJson)
-                     ?? `${r.status} ${r.statusText}: ${body}`;
-            throw decorate409(new Error(msg), bodyJson);
+            const msg = opts.formatError?.(req, r, text, json)
+                     ?? (json && typeof (json as Record<string, unknown>).message === 'string'
+                            ? String((json as Record<string, unknown>).message)
+                            : `${r.status} ${r.statusText}: ${text}`);
+            throw decorate409(new Error(msg), json);
         }
 
         if (!r.ok) {
-            const body = await r.text();
-            const bodyJson = safeJson(body);
-            const msg = opts.formatError?.(req, r, body, bodyJson)
-                     ?? `${r.status} ${r.statusText}: ${body}`;
+            const [text, json] = await readBody(r);
+            const msg = opts.formatError?.(req, r, text, json)
+                     ?? `${r.status} ${r.statusText}: ${text}`;
             throw new Error(msg);
         }
 
@@ -183,6 +184,22 @@ function safeJson(text: string): unknown | null {
     try { return JSON.parse(text); } catch { return null; }
 }
 
+/**
+ * Read an error-response body. Prefer `.json()` (tests commonly mock only
+ * that); fall back to `.text()` if json() throws. Returns both the raw
+ * text (for `formatError` callers that want to log it) and the parsed
+ * JSON (may be null when the body isn't parseable).
+ */
+async function readBody(r: Response): Promise<[string, unknown | null]> {
+    try {
+        const j = await r.clone().json();
+        return [JSON.stringify(j), j];
+    } catch {
+        const text = await r.text().catch(() => '');
+        return [text, safeJson(text)];
+    }
+}
+
 /** Attach status/body to 409 errors so conflict-resolvers can reach them. */
 function decorate409(err: Error, body: unknown): Error {
     (err as Error & { status?: number; body?: unknown }).status = 409;