fix(tools): resolve hermes CLI beside the interpreter in bot_mode_dm deliveries

Bot-to-bot message_agent delivery builds both transport argvs (local
teammate chat and peer dm) with a bare "hermes" as argv[0]. Since #96631
the delivery runner spawns under terminal_tool's isolated host-local
environment, which does not inherit the gateway's PATH — so on
docker/service installs (venv at /opt/hermes/.venv) every delivery exits
with FileNotFoundError: 'hermes'.

Resolve the CLI with bot_relay._hermes_cli() (#93590) — the venv sibling
of this interpreter, then shutil.which, then the bare name — at both
argv construction sites. The turn-lock matcher in _delivery_lock()
already matches argv[0] by basename, so absolute paths lock exactly as
before.

Fixes #100662

tests/tools/test_bot_mode_dm.py

@@ -16,7 +16,7 @@ from pathlib import Path
 
 import pytest
 
-from tools import bot_mode_dm, bot_mode_probe
+from tools import bot_mode_dm, bot_mode_probe, bot_relay
 
 
 @pytest.fixture(autouse=True)
@@ -234,6 +234,9 @@ def _runner_author(command):
 
 def test_local_delivery_command_and_ack(tmp_path, monkeypatch):
     calls = _capture_spawn(monkeypatch)
+    # These assertions target the -p/turn-args shape; pin the entrypoint resolution
+    # so the test stays hermetic across venvs that do/don't expose a sibling script.
+    monkeypatch.setattr(bot_relay, "_hermes_cli", lambda: "hermes")
     home = _managed_home(tmp_path, teammates=("researcher",))
     agent = _FakeAgent(home, title="Bot Chat")
 
@@ -295,6 +298,7 @@ def test_peer_delivery_command_pins_registry_profile_for_secondary_bots(
     tool-side roster (read from the machine-root config) validated the
     target."""
     calls = _capture_spawn(monkeypatch)
+    monkeypatch.setattr(bot_relay, "_hermes_cli", lambda: "hermes")
     home = _managed_home(tmp_path, peers=("spark",))
     # A reviewer-profile gateway context: the agent's session db lives under
     # that profile's home, so _agent_home() resolves there while the
@@ -316,6 +320,7 @@ def test_peer_delivery_command_pins_registry_profile_for_secondary_bots(
 
 def test_peer_delivery_command(tmp_path, monkeypatch):
     calls = _capture_spawn(monkeypatch)
+    monkeypatch.setattr(bot_relay, "_hermes_cli", lambda: "hermes")
     monkeypatch.setattr("socket.gethostname", lambda: "eri-mac.local")
     home = _managed_home(tmp_path, peers=("spark",))
     agent = _FakeAgent(home, title="Bot Chat")
@@ -341,6 +346,40 @@ def test_peer_delivery_command(tmp_path, monkeypatch):
     assert transport_argv == ["hermes", "-p", "default", "peer", "dm", "spark"]
 
 
+def test_delivery_pins_the_hermes_entrypoint_beside_this_interpreter(tmp_path, monkeypatch):
+    """A background delivery must not rely on PATH: the runner's service context
+    lacks the gateway's venv bin dir, so a bare ``hermes`` resolves to a system
+    install whose shebang picks the wrong interpreter and dies on import (#108628).
+    Both transports must invoke the entrypoint beside this interpreter instead."""
+    venv_bin = tmp_path / "venv" / ("Scripts" if sys.platform == "win32" else "bin")
+    venv_bin.mkdir(parents=True)
+    hermes_entry = venv_bin / ("hermes.exe" if sys.platform == "win32" else "hermes")
+    hermes_entry.write_text("#!/bin/sh\n", encoding="utf-8")
+    monkeypatch.setattr(sys, "executable", str(venv_bin / "python3"))
+
+    calls = _capture_spawn(monkeypatch)
+    home = _managed_home(tmp_path, teammates=("researcher",), peers=("spark",))
+    agent = _FakeAgent(home, title="Bot Chat")
+
+    result = json.loads(
+        bot_mode_dm.message_agent_tool(target="researcher", message="ping", agent=agent)
+    )
+    assert result["status"] == "sent"
+    mode, _dm_file, transport_argv = _runner_parts(calls[0]["command"])
+    assert mode == "query-file"
+    assert transport_argv[0] == str(hermes_entry)
+    assert transport_argv[1:] == ["-p", "researcher", "chat", "--in", "~", "-c", "Bot Chat",
+                                  "--create-if-missing", "-Q"]
+
+    result2 = json.loads(
+        bot_mode_dm.message_agent_tool(target="spark", message="ping", agent=agent)
+    )
+    assert result2["status"] == "sent"
+    mode, _dm_file, transport_argv = _runner_parts(calls[1]["command"])
+    assert mode == "stdin"
+    assert transport_argv == [str(hermes_entry), "-p", "default", "peer", "dm", "spark"]
+
+
 def test_peer_delivery_author_carries_the_sender_hostname_and_local_stays_bare(tmp_path, monkeypatch):
     """A peer dm crosses installs, so its author id is ``bot:<hostname>/<profile>``: the peer's own ``coder`` and a
     remote ``coder`` must not share one id. A teammate on this install still sees the bare ``bot:coder``."""

tools/bot_mode_dm.py

@@ -183,7 +183,7 @@ def message_agent_tool(target: str = "", message: str = "", task_id: Optional[st
             BOT_CHAT_TITLE, _handle, _hermes_root, _peers, _profile_name as _self_profile_name, _roster,
             is_bot_mode_managed,
         )
-        from tools.bot_relay import BOT_CHAT_TURN_ARGS
+        from tools.bot_relay import BOT_CHAT_TURN_ARGS, _hermes_cli
 
         if _session_title(agent) != BOT_CHAT_TITLE:
             return _err("message_agent is only available in a Bot Mode 'Bot Chat' session. "
@@ -231,7 +231,12 @@ def message_agent_tool(target: str = "", message: str = "", task_id: Optional[st
         # Pin the registry-owning profile: `hermes peer` resolves bot_peers via the profile-scoped
         # load_config(), while the roster above reads the machine-root config — the CLI must run
         # in that same profile or a secondary-profile bot sees an empty registry.
-        return _start_delivery(["hermes", "-p", _self_profile_name(root), "peer", "dm", dm_target], content,
+        # The delivery runs in a background service context whose PATH lacks the gateway's
+        # venv bin dir, so a bare "hermes" resolves to a system install and dies on import
+        # under the wrong interpreter (#108628). _hermes_cli pins the entrypoint beside
+        # this interpreter; _delivery_lock/_local_delivery_home match argv[0] by basename,
+        # so the absolute path stays compatible.
+        return _start_delivery([_hermes_cli(), "-p", _self_profile_name(root), "peer", "dm", dm_target], content,
                                f"@{peer_profile or peer_name} on peer '{peer_name}'", stdin_file=True,
                                author=peer_author, **delivery)
 
@@ -252,7 +257,7 @@ def message_agent_tool(target: str = "", message: str = "", task_id: Optional[st
         return _roster_err(f"No teammate named '{raw_target}' on this install, on a connected "
                            "machine, or on a registered peer. Pick a name from the roster "
                            "(roles are listed in your system prompt).")
-    return _start_delivery(["hermes", "-p", resolved, *BOT_CHAT_TURN_ARGS], content, f"@{_handle(resolved)}",
+    return _start_delivery([_hermes_cli(), "-p", resolved, *BOT_CHAT_TURN_ARGS], content, f"@{_handle(resolved)}",
                            stdin_file=False, profile_home=roster_homes[resolved], author=author, **delivery)