Neutralize </ctx-pack> sentinels in pack entry content

contextfun/cli.py

@@ -2037,7 +2037,7 @@ def cmd_pack(args: argparse.Namespace):
             lines.append("")
             lines.append("## Pinned context")
             for e in pinned_entries:
-                preview = (e["content"] or "").strip()
+                preview = _neutralize_pack_sentinels((e["content"] or "").strip())
                 if len(preview) > 500:
                     preview = preview[:497] + "..."
                 lines.append(f"- E{e['id']} S{e['session_id']} `{_entry_display_label(e)}`:\n\n  {preview}")
@@ -2053,7 +2053,7 @@ def cmd_pack(args: argparse.Namespace):
                     title += f" (types: {', '.join(sorted(focus))})"
                 lines.append(title)
                 for e in recent_entries:
-                    preview = (e["content"] or "").strip()
+                    preview = _neutralize_pack_sentinels((e["content"] or "").strip())
                     if len(preview) > 500:
                         preview = preview[:497] + "..."
                     lines.append(f"- E{e['id']} S{e['session_id']} `{_entry_display_label(e)}`:\n\n  {preview}")
@@ -2073,7 +2073,7 @@ def cmd_pack(args: argparse.Namespace):
             lines.append("")
             lines.append("Pinned context:")
             for e in pinned_entries:
-                preview = (e["content"] or "").strip().replace("\n", " ")
+                preview = _neutralize_pack_sentinels((e["content"] or "").strip().replace("\n", " "))
                 if len(preview) > 160:
                     preview = preview[:157] + "..."
                 lines.append(f"- E{e['id']} S{e['session_id']} {_entry_display_label(e)}: {preview}")
@@ -2086,13 +2086,20 @@ def cmd_pack(args: argparse.Namespace):
                 lines.append("")
                 lines.append("Recent entries:" + (f" (types: {', '.join(sorted(focus))})" if focus else ""))
                 for e in recent_entries:
-                    preview = (e["content"] or "").strip().replace("\n", " ")
+                    preview = _neutralize_pack_sentinels((e["content"] or "").strip().replace("\n", " "))
                     if len(preview) > 160:
                         preview = preview[:157] + "..."
                     lines.append(f"- E{e['id']} S{e['session_id']} {_entry_display_label(e)}: {preview}")
         print("\n".join(lines))
 
 
+def _neutralize_pack_sentinels(text: str) -> str:
+    # Prevent entry content from closing the outer <ctx-pack>…</ctx-pack> wrapper
+    # emitted by the resume skill (scripts/ctx_cmd.py). A zero-width space is
+    # invisible but breaks the literal tag match used by consumers.
+    return text.replace("</ctx-pack>", "</ctx-pack​>").replace("<ctx-pack>", "<ctx-pack​>")
+
+
 def _read_stdin_if_dash(text_arg):
     if text_arg == "-":
         return sys.stdin.read()

tests/test_pack_sentinel_guard.py

@@ -0,0 +1,58 @@
+"""Regression tests for _neutralize_pack_sentinels (contextfun/cli.py).
+
+Entry content that contains a literal </ctx-pack> would prematurely close the
+<ctx-pack>…</ctx-pack> wrapper emitted by the resume skill, so a consumer that
+splits on the literal tag mis-parses the pack. The guard inserts a zero-width
+space inside any such tag: the literal match breaks while the text stays
+visually identical.
+"""
+
+import importlib.util
+import unittest
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[1]
+CLI_PY = ROOT / "contextfun" / "cli.py"
+
+ZWSP = "​"
+
+
+def _load_cli_module():
+    spec = importlib.util.spec_from_file_location("ctx_cli_module", CLI_PY)
+    module = importlib.util.module_from_spec(spec)
+    assert spec is not None and spec.loader is not None
+    spec.loader.exec_module(module)
+    return module
+
+
+class PackSentinelGuardTests(unittest.TestCase):
+    def setUp(self):
+        self.cli = _load_cli_module()
+        self.guard = self.cli._neutralize_pack_sentinels
+
+    def test_closing_tag_no_longer_matches_literal(self):
+        out = self.guard("notes </ctx-pack> more")
+        self.assertNotIn("</ctx-pack>", out)
+        self.assertIn("</ctx-pack" + ZWSP + ">", out)
+
+    def test_opening_tag_no_longer_matches_literal(self):
+        out = self.guard("<ctx-pack> injected")
+        self.assertNotIn("<ctx-pack>", out)
+        self.assertIn("<ctx-pack" + ZWSP + ">", out)
+
+    def test_guarded_text_is_visually_identical_when_zwsp_stripped(self):
+        evil = "a </ctx-pack> b <ctx-pack> c"
+        self.assertEqual(self.guard(evil).replace(ZWSP, ""), evil)
+
+    def test_benign_text_is_unchanged(self):
+        benign = "ordinary entry with <other> tags & </closing> bits"
+        self.assertEqual(self.guard(benign), benign)
+
+    def test_multiple_occurrences_all_guarded(self):
+        out = self.guard("</ctx-pack> x </ctx-pack>")
+        self.assertNotIn("</ctx-pack>", out)
+        self.assertEqual(out.count("</ctx-pack" + ZWSP + ">"), 2)
+
+
+if __name__ == "__main__":
+    unittest.main()