diff --git a/ipyai/api_client.py b/ipyai/api_client.py
index 873bf52..95c5289 100644
--- a/ipyai/api_client.py
+++ b/ipyai/api_client.py
@@ -5,6 +5,7 @@
     contents, mk_tr_details)
 
 from .backend_common import BaseBackend, ConversationSeed, compact_tool, seed_to_flat_history
+from .lisette_compat import full_response_sentinel_text, is_full_response, strip_full_response_sentinel
 
 
 class _BridgeNS(dict):
@@ -40,6 +41,11 @@ def _emit(self, text):
         if text: self.display_text += text
         return text or ""
 
+    def _tool_result_for_outp(self, o):
+        content = o.get("content")
+        if is_full_response(content): return {**o, "content": full_response_sentinel_text(content)}
+        return o
+
     def format_item(self, o):
         if isinstance(o, ModelResponse):
             if tcs := getattr(contents(o), "tool_calls", None):
@@ -48,10 +54,10 @@ def format_item(self, o):
         if isinstance(o, dict) and "tool_call_id" in o:
             tc = self.tcs.pop(o["tool_call_id"], None)
             if tc is not None:
-                self.outp += mk_tr_details(o, tc, mx=self.mx)
+                self.outp += mk_tr_details(self._tool_result_for_outp(o), tc, mx=self.mx)
                 self.final_text = self.outp
                 args = json.loads(tc.function.arguments or "{}")
-                return self._emit(compact_tool(tc.function.name, args, o.get("content") or ""))
+                return self._emit(compact_tool(tc.function.name, args, strip_full_response_sentinel(o.get("content") or "")))
         res = super().format_item(o)
         self.final_text = self.outp
         return self._emit(res)
diff --git a/ipyai/kernel_bridge.py b/ipyai/kernel_bridge.py
index fead9f3..1f21006 100644
--- a/ipyai/kernel_bridge.py
+++ b/ipyai/kernel_bridge.py
@@ -2,6 +2,8 @@
 import ast, asyncio, json
 from queue import Empty
 
+from .lisette_compat import full_response_sentinel_text
+
 
 CUSTOM_TOOL_NAMES = ("pyrun", "bash", "start_bgterm", "write_stdin", "close_bgterm", "lnhashview_file", "exhash_file", "list_pyskills")
 _INJECT_IMPORTS = dict(bash="from safecmd import bash", start_bgterm="from bgterm import start_bgterm",
@@ -120,7 +122,7 @@ async def call_tool(self, name, args=None):
         text = res if isinstance(res, str) else json.dumps(res, ensure_ascii=False, default=str)
         if exprs.get("_full"):
             from lisette.core import FullResponse
-            return FullResponse(text)
+            return FullResponse(full_response_sentinel_text(text))
         return text
 
     async def read_var(self, name):
diff --git a/ipyai/lisette_compat.py b/ipyai/lisette_compat.py
new file mode 100644
index 0000000..a78bc4e
--- /dev/null
+++ b/ipyai/lisette_compat.py
@@ -0,0 +1,25 @@
+"Compatibility helpers for lisette response formatting contracts."
+
+FULL_RESPONSE_SENTINEL = "𝍁"
+
+
+def is_full_response(value):
+    "Return whether `value` is a lisette-style FullResponse without importing lisette."
+    return any(cls.__name__ == "FullResponse" for cls in type(value).__mro__)
+
+
+def full_response_sentinel_text(value):
+    "Wrap `value` in lisette's serialization-safe no-truncation sentinel."
+    text = str(value)
+    if len(text) > 2 and text[0] == FULL_RESPONSE_SENTINEL and text[-1] == FULL_RESPONSE_SENTINEL:
+        return text
+    return f"{FULL_RESPONSE_SENTINEL}{text}{FULL_RESPONSE_SENTINEL}"
+
+
+def strip_full_response_sentinel(value):
+    "Strip lisette's no-truncation sentinel from display text."
+    if not isinstance(value, str): return value
+    text = str(value)
+    if len(text) > 2 and text[0] == FULL_RESPONSE_SENTINEL and text[-1] == FULL_RESPONSE_SENTINEL:
+        return text[1:-1]
+    return value