diff --git a/hermes_cli/main.py b/hermes_cli/main.py
index a57d4d953de..caca5e6a8a3 100644
--- a/hermes_cli/main.py
+++ b/hermes_cli/main.py
@@ -13525,8 +13525,9 @@ def main():
     )
     _add_session_filter_args(
         sessions_prune,
-        "Delete sessions older than AGE — days if bare number (default: 90), "
-        "or a duration like '5h'/'2d'/'1w', or an ISO timestamp",
+        "Delete sessions older than AGE — days if bare number, or a duration "
+        "like '5h'/'2d'/'1w', or an ISO timestamp (bare prune with no filters "
+        "defaults to 90 days; any filter matches all ages)",
     )
     sessions_prune.add_argument(
         "--include-archived",
@@ -13741,16 +13742,16 @@ def main():
                 format_epoch,
             )
 
-            # Preserve the historical default: bare `hermes sessions prune`
-            # means "older than 90 days" — and --source keeps that default
-            # too (it predates the extended filters; scripts may rely on
-            # `prune --source X --yes` meaning >90d). Any NEW attribute
-            # filter suppresses the implicit cutoff so e.g.
-            # `prune --model sonnet` matches ALL sessions for that model.
+            # Preserve the historical default ONLY for a truly bare
+            # `hermes sessions prune`: no time window and no filters at all
+            # means "older than 90 days". ANY filter — including --source —
+            # suppresses the implicit cutoff, so `prune --source cron`
+            # matches ALL cron sessions regardless of age. The preview +
+            # confirmation below (count, oldest/newest) is the safety net.
             _non_time_filters = any(
                 getattr(args, a, None) is not None
                 for a in (
-                    "title", "end_reason", "cwd",
+                    "source", "title", "end_reason", "cwd",
                     "min_messages", "max_messages", "model", "provider",
                     "user", "chat_id", "chat_type", "branch",
                     "min_tokens", "max_tokens", "min_cost", "max_cost",
@@ -13797,11 +13798,19 @@ def main():
                 print(f"No sessions match ({describe_filters(filters)}).")
                 return
 
+            # Candidates are ordered oldest-first — surface the age span so
+            # the confirmation makes the blast radius obvious.
+            _oldest = candidates[0].get("started_at")
+            _newest = candidates[-1].get("started_at")
+            _span = (
+                f"oldest {format_epoch(_oldest)}, newest {format_epoch(_newest)}"
+            )
+
             if args.dry_run or not args.yes:
                 shown = candidates if args.dry_run else candidates[:15]
                 print(
                     f"{len(candidates)} session(s) match "
-                    f"({describe_filters(filters)}):"
+                    f"({describe_filters(filters)}; {_span}):"
                 )
                 for s in shown:
                     title = (s.get("title") or "")[:36]
@@ -13819,7 +13828,7 @@ def main():
 
             if not args.yes:
                 if not _confirm_prompt(
-                    f"{verb} these {len(candidates)} session(s)? [y/N] "
+                    f"{verb} these {len(candidates)} session(s) ({_span})? [y/N] "
                 ):
                     print("Cancelled.")
                     return
diff --git a/hermes_cli/web_server.py b/hermes_cli/web_server.py
index 242983561b5..58cf4b33dbd 100644
--- a/hermes_cli/web_server.py
+++ b/hermes_cli/web_server.py
@@ -8234,11 +8234,28 @@ async def prune_sessions_endpoint(body: SessionPrune):
     )
     if body.older_than_days is not None and body.older_than_days < 1 and not has_window:
         raise HTTPException(status_code=400, detail="older_than_days must be >= 1")
+    # Mirror the CLI: the implicit 90-day cutoff only applies to a truly bare
+    # prune. Any attribute filter (source, title, model, ...) suppresses it
+    # unless the caller explicitly sent older_than_days.
+    _attr_filters_set = any(
+        getattr(body, f) is not None
+        for f in (
+            "source", "title_like", "end_reason", "cwd_prefix",
+            "min_messages", "max_messages", "model_like", "provider",
+            "user_id", "chat_id", "chat_type", "branch_like",
+            "min_tokens", "max_tokens", "min_cost", "max_cost",
+            "min_tool_calls", "max_tool_calls",
+        )
+    )
+    _older_than_explicit = "older_than_days" in body.model_fields_set
+    _effective_older_than = body.older_than_days
+    if has_window or (_attr_filters_set and not _older_than_explicit):
+        _effective_older_than = None
     profile_home = _cron_profile_home(body.profile)[1] if body.profile else get_hermes_home()
     db = _open_session_db_for_profile(body.profile)
     try:
         filters = dict(
-            older_than_days=None if has_window else body.older_than_days,
+            older_than_days=_effective_older_than,
             source=(body.source or None),
             started_before=body.started_before,
             started_after=body.started_after,
@@ -8267,6 +8284,9 @@ async def prune_sessions_endpoint(body: SessionPrune):
                 "ok": True,
                 "removed": 0,
                 "matched": len(rows),
+                # Rows are ordered oldest-first.
+                "oldest_started_at": rows[0]["started_at"] if rows else None,
+                "newest_started_at": rows[-1]["started_at"] if rows else None,
                 "sessions": [
                     {
                         "id": r["id"],
diff --git a/tests/hermes_cli/test_dashboard_admin_endpoints.py b/tests/hermes_cli/test_dashboard_admin_endpoints.py
index 6650d055a42..e0e083c5d19 100644
--- a/tests/hermes_cli/test_dashboard_admin_endpoints.py
+++ b/tests/hermes_cli/test_dashboard_admin_endpoints.py
@@ -452,6 +452,36 @@ class TestSessionManagementEndpoints:
             "/api/sessions/prune", json={"older_than_days": 0}
         ).status_code == 400
 
+    def test_prune_attr_filter_suppresses_default_cutoff(self):
+        # An attribute filter without an explicit older_than_days matches all
+        # ages (mirrors the CLI: any filter disables the implicit 90-day
+        # default). dry_run so nothing is deleted; the seeded session is
+        # recent + ended, so it would be invisible under a 90-day cutoff.
+        from hermes_state import SessionDB
+
+        db = SessionDB()
+        db.create_session(session_id="sess-recent-ended", source="cli")
+        db.end_session("sess-recent-ended", "completed")
+        db.close()
+
+        r = self.client.post(
+            "/api/sessions/prune",
+            json={"source": "cli", "dry_run": True},
+        )
+        assert r.status_code == 200
+        body = r.json()
+        assert body["matched"] >= 1
+        assert "oldest_started_at" in body and "newest_started_at" in body
+
+    def test_prune_explicit_older_than_kept_with_attr_filter(self):
+        # Explicit older_than_days is honored even alongside attribute filters.
+        r = self.client.post(
+            "/api/sessions/prune",
+            json={"source": "cli", "older_than_days": 9999, "dry_run": True},
+        )
+        assert r.status_code == 200
+        assert r.json()["matched"] == 0
+
 
 class TestSkillsHubSearchEndpoint:
     @pytest.fixture(autouse=True)
diff --git a/tests/hermes_cli/test_sessions_delete.py b/tests/hermes_cli/test_sessions_delete.py
index 5866d31102b..0c54da1cf15 100644
--- a/tests/hermes_cli/test_sessions_delete.py
+++ b/tests/hermes_cli/test_sessions_delete.py
@@ -1,5 +1,7 @@
 import sys
 
+import pytest
+
 
 def test_sessions_delete_accepts_unique_id_prefix(monkeypatch, capsys):
     import hermes_cli.main as main_mod
@@ -128,3 +130,93 @@ def test_sessions_prune_handles_eoferror_on_confirm(monkeypatch, capsys):
 
     output = capsys.readouterr().out
     assert "Cancelled" in output
+
+
+def _run_prune(monkeypatch, capsys, argv_tail, candidates=None):
+    """Run `hermes sessions prune <argv_tail>` against a FakeDB, capturing
+    the filter kwargs passed to list_prune_candidates. Auto-confirms."""
+    import hermes_cli.main as main_mod
+    import hermes_state
+
+    seen = {}
+    rows = candidates if candidates is not None else [
+        {
+            "id": "20260101_000000_aaaaaa",
+            "source": "cron",
+            "title": "oldest run",
+            "started_at": 1_600_000_000.0,
+            "ended_at": 1_600_000_100.0,
+            "message_count": 2,
+            "archived": 0,
+        },
+        {
+            "id": "20260601_000000_bbbbbb",
+            "source": "cron",
+            "title": "newest run",
+            "started_at": 1_700_000_000.0,
+            "ended_at": 1_700_000_100.0,
+            "message_count": 4,
+            "archived": 0,
+        },
+    ]
+
+    class FakeDB:
+        def list_prune_candidates(self, **kwargs):
+            seen.update(kwargs)
+            return rows
+
+        def prune_sessions(self, **kwargs):
+            return len(rows)
+
+        def close(self):
+            pass
+
+    monkeypatch.setattr(hermes_state, "SessionDB", lambda: FakeDB())
+    monkeypatch.setattr(
+        sys, "argv", ["hermes", "sessions", "prune", *argv_tail]
+    )
+    monkeypatch.setattr("builtins.input", lambda _prompt="": "y")
+    main_mod.main()
+    return seen, capsys.readouterr().out
+
+
+def test_sessions_prune_bare_keeps_90_day_default(monkeypatch, capsys):
+    """A truly bare `hermes sessions prune` keeps the implicit 90-day cutoff."""
+    import time as _time
+
+    filters, _out = _run_prune(monkeypatch, capsys, [])
+    assert filters["started_before"] is not None
+    assert filters["started_before"] == pytest.approx(
+        _time.time() - 90 * 86400, abs=60
+    )
+
+
+def test_sessions_prune_source_matches_all_ages(monkeypatch, capsys):
+    """--source alone suppresses the implicit 90-day cutoff (all ages)."""
+    filters, _out = _run_prune(monkeypatch, capsys, ["--source", "cron"])
+    assert filters["started_before"] is None
+    assert filters["started_after"] is None
+    assert filters["source"] == "cron"
+
+
+def test_sessions_prune_source_with_explicit_time_respected(monkeypatch, capsys):
+    """--source + explicit --older-than keeps the user's bound."""
+    import time as _time
+
+    filters, _out = _run_prune(
+        monkeypatch, capsys, ["--source", "cron", "--older-than", "30"]
+    )
+    assert filters["started_before"] == pytest.approx(
+        _time.time() - 30 * 86400, abs=60
+    )
+    assert filters["source"] == "cron"
+
+
+def test_sessions_prune_preview_shows_oldest_newest(monkeypatch, capsys):
+    """Confirmation preview surfaces count + oldest/newest session times."""
+    from hermes_cli.session_filters import format_epoch
+
+    _filters, out = _run_prune(monkeypatch, capsys, ["--source", "cron"])
+    assert "2 session(s) match" in out
+    assert f"oldest {format_epoch(1_600_000_000.0)}" in out
+    assert f"newest {format_epoch(1_700_000_000.0)}" in out
diff --git a/website/docs/user-guide/sessions.md b/website/docs/user-guide/sessions.md
index 66631448400..2e1ec54640f 100644
--- a/website/docs/user-guide/sessions.md
+++ b/website/docs/user-guide/sessions.md
@@ -348,8 +348,10 @@ hermes sessions prune --newer-than 5h
 # Explicit window with absolute timestamps
 hermes sessions prune --after "2026-07-05 09:00" --before "2026-07-05 14:30"
 
-# Only prune sessions from a specific platform
-hermes sessions prune --source telegram --older-than 60
+# Only prune sessions from a specific platform (all ages — any filter
+# disables the implicit 90-day default)
+hermes sessions prune --source telegram
+hermes sessions prune --source cron --older-than 60   # add a time flag to narrow
 
 # More filters — all AND together
 hermes sessions prune --newer-than 5h --title "smoke test"   # title substring
@@ -380,10 +382,12 @@ Attribute filters: `--source` (platform, exact), `--title` / `--model` /
 exact), `--end-reason`, `--user`, `--chat-id`, `--chat-type` (exact),
 `--cwd` (path prefix), plus numeric bounds `--min/--max-messages`,
 `--min/--max-tokens` (input+output), `--min/--max-cost` (USD, actual falling
-back to estimated), and `--min/--max-tool-calls`. Using any attribute filter
-(other than `--source`) disables the implicit 90-day default, so
-`hermes sessions prune --model gpt-4o` matches all ages — add a time flag to
-narrow it.
+back to estimated), and `--min/--max-tool-calls`. Using any filter disables
+the implicit 90-day default, so `hermes sessions prune --source cron` or
+`--model gpt-4o` matches all ages — add a time flag to narrow it. Only a
+completely bare `hermes sessions prune` keeps the 90-day cutoff. Every
+non-`--yes` run shows the match count plus the oldest and newest matching
+session before asking for confirmation.
 
 Archived sessions are skipped by default; pass `--include-archived` to
 delete them too.