fix: hide memory tool from cron agents

Cron agents are constructed with skip_memory=True, so the memory
backend is not initialised — exposing the memory tool only gives the
model an unbacked tool that fails at runtime with 'Memory is not
available.'  Add 'memory' to _resolve_cron_disabled_toolsets() so the
tool is stripped from the schema before the model can call it.

Fixes #38129.

Co-authored-by: Paolo Shamoon <Paolo@Dylans-Mac-Studio.local>

cron/scheduler.py

@@ -165,17 +165,19 @@ class CronPromptInjectionBlocked(Exception):
 def _resolve_cron_disabled_toolsets(cfg: dict) -> list[str]:
     """Toolsets a cron-spawned agent must never receive.
 
-    Three protected toolsets are always disabled in cron context:
+    Four protected toolsets are always disabled in cron context:
       - ``cronjob`` — would let a cron-spawned agent schedule more cron jobs
       - ``messaging`` — interactive, needs a live gateway session
       - ``clarify`` — interactive, blocks waiting for user input
+      - ``memory`` — cron agents are constructed with ``skip_memory=True``, so
+        exposing this tool only gives the model an unbacked tool that fails
 
     User-level ``agent.disabled_toolsets`` from config.yaml is layered on top
     so per-job ``enabled_toolsets`` cannot bypass policy that applies to
     ordinary agent runs (#25752 — LLM-supplied enabled_toolsets was widening
     past config.yaml's denylist).
     """
-    disabled = ["cronjob", "messaging", "clarify"]
+    disabled = ["cronjob", "messaging", "clarify", "memory"]
     agent_cfg = (cfg or {}).get("agent") or {}
     user_disabled = agent_cfg.get("disabled_toolsets") or []
     for name in user_disabled:

tests/cron/test_scheduler.py

@@ -533,6 +533,49 @@ class TestRunJobSessionPersistence:
             yield fake_db, mock_agent_cls
 
 
+    def test_run_job_memory_toolset_disabled_in_cron(self, tmp_path):
+        """memory toolset must be disabled in cron sessions — issue #38129.
+
+        Cron agents are constructed with skip_memory=True, so the memory
+        backend is not initialised.  Exposing the memory tool only gives the
+        model an unbacked tool that fails at runtime with
+        "Memory is not available."  Hiding it from the schema prevents that.
+        """
+        job = {
+            "id": "memory-hide-job",
+            "name": "test",
+            "prompt": "hello",
+        }
+        with self._run_job_patches(tmp_path) as (fake_db, mock_agent_cls):
+            run_job(job)
+
+        kwargs = mock_agent_cls.call_args.kwargs
+        assert "memory" in (kwargs["disabled_toolsets"] or []), (
+            "memory toolset should be disabled in cron to match skip_memory=True"
+        )
+
+    def test_run_job_disables_memory_even_when_per_job_enables_it(self, tmp_path):
+        """Cron runs pass skip_memory=True, so memory must not be exposed.
+
+        A cron job can request the memory tool through enabled_toolsets, but
+        there is no MemoryStore injected for cron agents.  Keep memory in the
+        disabled set so AIAgent filters the unbacked tool out before the model
+        can call it and receive "Memory is not available" failures.
+        """
+        job = {
+            "id": "memory-toolset-job",
+            "name": "test",
+            "prompt": "remember what you learn",
+            "enabled_toolsets": ["memory", "file"],
+        }
+        with self._run_job_patches(tmp_path) as (fake_db, mock_agent_cls):
+            run_job(job)
+
+        kwargs = mock_agent_cls.call_args.kwargs
+        assert kwargs["skip_memory"] is True
+        assert kwargs["enabled_toolsets"] == ["memory", "file"]
+        assert "memory" in kwargs["disabled_toolsets"]
+
     def test_tick_skips_due_jobs_while_dispatch_is_paused(self, tmp_path):
         """The drain gate runs before advancing a due job's schedule."""
         from cron.scheduler import tick