diff --git a/ouroboros/tools/shell.py b/ouroboros/tools/shell.py
index acc83f8e1..f5a3d2d4f 100644
--- a/ouroboros/tools/shell.py
+++ b/ouroboros/tools/shell.py
@@ -532,7 +532,7 @@ def _run_shell(
         _record_scratch_fingerprints(ctx, scratch_abs)
         return (
             f"⚠️ TOOL_TIMEOUT (run_command): command exceeded the per-command timeout of {timeout_sec}s "
-            f"and its process group was killed; a child it detached may survive untracked (root={binding.root}, cwd={work_dir}). NOTE: this is the per-command "
+            f"and the host killed what it could still reach of its process tree; a background child may survive untracked (root={binding.root}, cwd={work_dir}). NOTE: this is the per-command "
             f"FOREGROUND timeout, NOT the task deadline. For genuinely long-running compute (training, "
             f"sampling, large builds/downloads), start it with start_service and poll "
             f"service_status/service_logs while you do other work, or pass an explicit timeout_sec=<seconds> "
@@ -681,7 +681,7 @@ def get_tools() -> List[ToolEntry]:
                 "cmd MUST be an array of strings, never one shell string. A builtin as cmd[0] (cd, export, ...) "
                 "is refused: use cwd= or [\"sh\", \"-c\", \"cd x && a | b\"] (also for pipes/chaining). "
                 "A background child (&, nohup) is no service: holding stdout/stderr it stalls the call until "
-                "timeout_sec, and afterwards nothing tracks or stops it (use start_service). "
+                "timeout_sec, and once the call returns nothing tracks it (use start_service). "
                 "Prefer read_file, search_code/query_code, write_file/edit_text to cat/head/sed, grep/find, redirects."
             ),
             "parameters": {"type": "object", "properties": {
diff --git a/tests/test_run_command_schema_truth.py b/tests/test_run_command_schema_truth.py
index efd265a8e..f4a33651d 100644
--- a/tests/test_run_command_schema_truth.py
+++ b/tests/test_run_command_schema_truth.py
@@ -61,9 +61,12 @@ def test_description_states_the_bare_builtin_refusal_and_the_sh_c_escape():
 
 def test_description_states_what_happens_to_a_background_child():
     description = _schema()["description"]
-    # What the empirical tests below prove: the call stalls until timeout_sec
-    # while the child holds stdio, and the child survives untracked either way.
-    for word in ("&", "nohup", "stalls the call until timeout_sec", "nothing tracks or stops it", "start_service"):
+    # What the empirical tests below prove on every platform: the call stalls until
+    # timeout_sec while the child holds stdio, and nothing tracks the child afterwards.
+    # Whether the timeout kill still REACHES it is the platform's business (Linux can
+    # resolve the exited shell's process group and kills it, macOS cannot and it
+    # survives), so the description promises neither a cleanup nor a survival.
+    for word in ("&", "nohup", "stalls the call until timeout_sec", "once the call returns nothing tracks it", "start_service"):
         assert word in description, word
     assert "killed" not in description and "cleaned up" not in description  # no promise the host does not keep
 
@@ -92,10 +95,11 @@ def test_background_child_holding_stdout_makes_the_call_wait_until_timeout(tmp_p
     try:
         assert result.startswith("⚠️ TOOL_TIMEOUT"), result
         assert elapsed >= 0.9, elapsed
-        # "nothing tracks or stops it": the shell exited at once, so the timeout's
-        # group kill had no tree left — the backgrounded child is still running.
+        # "once the call returns nothing tracks it": the shell exited at once. On
+        # Linux the timeout kill still resolves the dead shell's process group and
+        # takes the child with it; on macOS it cannot and the child keeps running.
+        # Either way the host holds no handle on it.
         alive = subprocess.run(["pgrep", "-f", marker], capture_output=True, text=True).stdout.split()
-        assert alive, "the backgrounded child did not outlive the timeout kill"
         assert not any(str(proc.pid) in alive for proc in list(_active_subprocesses)), "nothing tracks it"
     finally:
         subprocess.run(["pkill", "-f", marker], check=False)
diff --git a/tests/test_shell_extraction.py b/tests/test_shell_extraction.py
index f3e2f05c0..4aebefa1b 100644
--- a/tests/test_shell_extraction.py
+++ b/tests/test_shell_extraction.py
@@ -112,9 +112,11 @@ def test_shell_catalog_schema_bytes_and_handler_owners_are_stable():
     # Workflow scope: explicit saved-setting references and lazy-output guidance.
     # run_command states its real contract: only a bare builtin as cmd[0] is
     # refused, a background child stalls the call and is never tracked after it
-    # (tests/test_run_command_schema_truth.py).
+    # (tests/test_run_command_schema_truth.py). Rolled once more: the sentence no
+    # longer says the child is never STOPPED, which is false where the timeout kill
+    # still reaches the exited shell's process group (Linux).
     assert hashlib.sha256(schema_bytes).hexdigest() == (
-        "61a0e6006f609e84e7e9f71b82e376896a0fc9287b295fe75e6fe22d96e870e7"
+        "7d7a07b763cec4e8fc95bdfb733c2b8362bb8c0f0648b33825b56e52dccda4ce"
     )
     original = json.loads(schema_bytes)
     for schema in original:
@@ -129,7 +131,7 @@ def test_shell_catalog_schema_bytes_and_handler_owners_are_stable():
     )
     assert hashlib.sha256(json.dumps(original, sort_keys=True, ensure_ascii=False,
                                     separators=(",", ":")).encode()).hexdigest() == (
-        "d1ee448cd3c283f769dfc2a0de3d2771d7270720931223d64757575ab42a54f5"
+        "c6504272bceed19cc138a9cc8ee98a04db2f6ac3b41d70fdacbc4fa4022542bc"
     )
     assert {
         entry.name: (entry.handler.__module__, entry.handler.__name__)