fix(issue-50): an injected record holds its session whatever its FIFO place; the ambient pane claim locks the caller's server (reviews 5a09a13f F-A, e8e471ff R1)

open_jobs reports a live pending record nobody signals on as `injected`:
its producer registered and injected it without a waiter (create
--onboard, a job sent by hand), so it holds the session like a running or
admitted job, and a waiter of the same second with a lower job id, or one
registered a moment earlier and still in its preflight, no longer passes
it in the FIFO. The waiter signals on its own record before its first
scan, so its record is never mistaken for one.

lib_py.pane_lock resolves the shim's ambient target (no -L,
HERDR_SESSION_NAME empty or `default`) to the server of the pane the
caller runs in - HERDR_SESSION, else HERDR_SOCKET_PATH's layout, as
lib.sh _herdr_caller_server reads them - so an ambient and a named call
into one server claim under one lock; outside a pane it stays the
default server's.

Tests: u2h (the tie, the later-registered onboarding, the signalled
control), u1/u4 labels, c10 forces the same-second registration, p1b,
s2 (real herdr: held lock stops both call forms; mixed concurrent calls
take distinct panes). Two FIFO fixtures now carry a waiter's signal.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

.agents/skills/lib.sh

@@ -1501,7 +1501,9 @@ _herdr_scope_is_pane_inherited() {
 # in the shim heredoc, which stays byte-identical (test_issue23_24 S11).
 #
 # _mam_pane_claim_target <herdr argv...>: prints the server a new-session call
-# targets ("" for the default one); rc 1 for any other call.
+# names ("" for the ambient target, which lib_py.pane_lock resolves to the
+# caller pane's server - the one herdr answers on - or the default server);
+# rc 1 for any other call.
 _mam_pane_claim_target() {
   local sess="${HERDR_SESSION_NAME:-}"
   while [ "${1:-}" = "-L" ]; do sess="${2:-}"; shift 2 || return 1; done

.agents/skills/lib_py/delegation/wrapper.py

@@ -268,9 +268,14 @@ def open_jobs(registry_dir: str, session: str, job_id: str, now: Optional[int] =
            within DISPATCH_SIGNAL_WINDOW, or - never signalled - created within
            its own ack_timeout_sec: a producer that registers and injects
            without a waiter (create --onboard) waits that long for `started`
-           (review 55219be1 R2). A live pending record whose admission names
+           (review 55219be1 R2). Such a never-signalled record is reported as
-           its current dispatch token is reported as `admitted`: it holds the
+           `injected` and a live pending record whose admission names its
-           session as a running job does, whatever its place in the FIFO.
+           current dispatch token as `admitted`: both hold the session as a
+           running job does, whatever their place in the FIFO - the prompt is
+           already in the pane (review 5a09a13f F-A: in the FIFO an `injected`
+           record of the same second lost to a lower job id). A waiter's own
+           record is unsignalled only until its first scan (wait_open_jobs
+           signals first).
     stale: [(job_id, reason)] - non-terminal records nothing has touched for
            longer than that: a wrapper killed before or while dispatching, a
            zombie's unclosed record, an onboarding never acknowledged. They
@@ -307,17 +312,21 @@ def open_jobs(registry_dir: str, session: str, job_id: str, now: Optional[int] =
                 seen, window = _parse_ts(rec.get("created_at")), _int_field(rec, "ack_timeout_sec", DEFAULT_ACK_TIMEOUT_SEC)
                 why = f"no dispatch signal and no started within {window}s"
             if seen is not None and now - seen <= window:
-                admitted = bool(rec.get(ADMITTED_TOKEN_FIELD)) and \
+                if not rec.get(DISPATCH_SIGNAL_FIELD):
-                    rec.get(ADMITTED_TOKEN_FIELD) == rec.get("dispatch_token")
+                    kind = "injected"
-                live.append((str(rec.get("created_at") or ""), other, "admitted" if admitted else status))
+                elif rec.get(ADMITTED_TOKEN_FIELD) and rec.get(ADMITTED_TOKEN_FIELD) == rec.get("dispatch_token"):
+                    kind = "admitted"
+                else:
+                    kind = status
+                live.append((str(rec.get("created_at") or ""), other, kind))
             else:
                 stale.append((other, f"pending, {why}"))
     return live, stale
 
 
 def _first_in_line(live, mine) -> bool:
-    """No live running or admitted job, and `mine` earliest among the live
+    """No live running, admitted or injected job, and `mine` earliest among
-    pending ones (FIFO by (created_at, job_id))."""
+    the live pending ones (FIFO by (created_at, job_id))."""
     if any(st != "pending" for _c, _j, st in live):
         return False
     return min([(c, j) for c, j, _st in live] + [mine]) == mine
@@ -449,9 +458,12 @@ def wait_open_jobs(a: argparse.Namespace) -> str:
     running (_started_own). The bound
     is min(--wait-s, this job's remaining wall clock). The identity is pinned
     at the start: --dispatch-token (the token the wrapper read for this
-    attempt), else the record's token read once. Every DISPATCH_SIGNAL_EVERY s
+    attempt), else the record's token read once. The waiter signals on its own
-    the waiter signals on its own record so later waiters see it alive; a
+    record before its first scan - an unsignalled live record is one a
-    waiter whose wrapper is gone stops (OwnerGone) and its signal goes stale.
+    producer injected without a waiter (open_jobs: `injected`), and this one
+    is not - and every DISPATCH_SIGNAL_EVERY s after, so other waiters see it
+    alive; a waiter whose wrapper is gone stops (OwnerGone) and its signal
+    goes stale.
     With --hold the admission is kept alive after the answer (_start_hold)."""
     me = _load_record(a.registry_dir, a.job) or {}
     token = getattr(a, "dispatch_token", None) or me.get("dispatch_token")
@@ -465,6 +477,9 @@ def wait_open_jobs(a: argparse.Namespace) -> str:
         rec = _load_record(a.registry_dir, a.job)
         if not _own(rec, token, a.agent_session):
             return "clear" if _started_own(rec, token, a.agent_session) else "superseded"
+        if last_signal is None or now - last_signal >= DISPATCH_SIGNAL_EVERY:
+            _signal_dispatch_wait(a.registry_dir, a.job, token, a.agent_session)
+            last_signal = now
         live, stale = open_jobs(a.registry_dir, a.agent_session, a.job, now)
         for other, reason in stale:
             if other not in reported:
@@ -476,9 +491,6 @@ def wait_open_jobs(a: argparse.Namespace) -> str:
             return "clear"
         if now >= deadline:
             return "busy " + " ".join(j for _c, j, _st in live)
-        if last_signal is None or now - last_signal >= DISPATCH_SIGNAL_EVERY:
-            _signal_dispatch_wait(a.registry_dir, a.job, token, a.agent_session)
-            last_signal = now
         _sleep(a, 1)
 
 

.agents/skills/lib_py/pane_lock.py

@@ -8,7 +8,13 @@ and the later `agent start` failed with agent_pane_busy. The shim now holds
 one lock per server from the choice to the claim.
 
   pane_lock.py path --session S   the lock file of herdr session S, under the
-                                  HOME whose socket the session uses
+                                  HOME whose socket the session uses. S empty
+                                  (or `default`) is the shim's ambient target:
+                                  herdr then answers on the server of the pane
+                                  this runs in (HERDR_SESSION / HERDR_SOCKET_PATH,
+                                  as lib.sh _herdr_caller_server reads them), or
+                                  the default server outside any pane - the
+                                  lock is that server's (review e8e471ff R1)
   pane_lock.py acquire --fd N     flock(LOCK_EX) on the inherited fd N; prints
                                   `locked`, or `timeout` once MAM_PANE_CLAIM_WAIT_S
                                   (default 120, minimum 1) has passed
@@ -32,9 +38,26 @@ from lib_py import ints
 DEFAULT_WAIT_S = 120
 
 
+def caller_server(env: Mapping[str, str]) -> str:
+    """The server whose pane this process runs in, by the pane's exports:
+    HERDR_SESSION when present, else HERDR_SOCKET_PATH's layout
+    ($HOME/.config/herdr/herdr.sock -> default, .../sessions/<name>/herdr.sock
+    -> name); "" outside a pane or for an unrecognised layout."""
+    if env.get("HERDR_SESSION"):
+        return env["HERDR_SESSION"]
+    sock = env.get("HERDR_SOCKET_PATH") or ""
+    if sock.endswith("/.config/herdr/herdr.sock"):
+        return "default"
+    if sock.endswith("/herdr.sock") and "/.config/herdr/sessions/" in sock:
+        return sock[:-len("/herdr.sock")].rsplit("/", 1)[-1]
+    return ""
+
+
 def lock_path(session: Optional[str], env: Mapping[str, str]) -> str:
     home = env.get("HOME") or env.get("HOME_DIR") or os.path.expanduser("~")
-    return os.path.join(home, ".local", "state", "mam", "pane-lock", (session or "default") + ".lock")
+    if session in (None, "", "default"):
+        session = caller_server(env) or "default"
+    return os.path.join(home, ".local", "state", "mam", "pane-lock", session + ".lock")
 
 
 def wait_s(env: Mapping[str, str]) -> int:

tests/test_issue26_ints.py

@@ -88,7 +88,8 @@ INPUTS = ["30", "0700", "0900", " 30 ", "0", "-5", "abc", "", "1e3", "9999999999
 # DELEGATE_JOB_/RECONCILE_…:-<digit>…}` that is neither here nor normalised
 # through INT_KNOBS, so a new knob has to be classified to land.
 # Issue #17 item 4: MAM_DELEGATE_FAIL_CLOSED and MAM_STALL_WATCH are read by
-# lib_py/delegation/wrapper.py now, not by shell code.
+# lib_py/delegation/wrapper.py now, not by shell code; MAM_PANE_CLAIM_WAIT_S
+# (minimum 1, default 120) by lib_py/pane_lock.py (test_issue50_pane_lock P5).
 NOT_ARITHMETIC = {
     "MAM_ALLOW_UNSIGNED_DISPATCH": "string compare", "MAM_DELEGATE_JOB_NO_MAIN": "string compare",
     "MAM_NO_AUTOSTART": "string compare", "MAM_SHIM_DEBUG": "string compare",

tests/test_issue50_dispatch.py

@@ -115,6 +115,8 @@ def test_u1_open_jobs_table(tmp_path, status, age, signal, ack, want):
     got = {j for _c, j, _s in live}, {j for j, _r in stale}
     if want == "live":
         assert got == ({other}, set())
+        if status == "pending":   # never signalled: injected by its producer, a holder; signalled: a waiter in the FIFO
+            assert live[0][2] == ("injected" if signal is None else "pending")
     elif want == "stale":
         assert got == (set(), {other}), got
         assert stale[0][1].startswith(status + ", no ")
@@ -169,8 +171,8 @@ def test_u2_clear_only_when_no_live_running_and_this_job_is_the_earliest_pending
     # A ends: clear
     _edit(tmp_path, a, status="completed")
     assert decide.wait_open_jobs(_ns(tmp_path, me)) == "clear"
-    # an earlier live pending waiter B: this job waits behind it (busy at the bound)
+    # an earlier live pending waiter B (signalled: a waiter is on it): this job waits behind it (busy at the bound)
-    b = _register(tmp_path, created_at=_iso(time.time() - 30))
+    b = _register(tmp_path, created_at=_iso(time.time() - 30), dispatch_wait_at=_iso(time.time()))
     assert decide.wait_open_jobs(_ns(tmp_path, me)) == f"busy {b}"
     # a later one does not hold this job up
     _edit(tmp_path, b, created_at=_iso(time.time() + 30))
@@ -180,11 +182,32 @@ def test_u2_clear_only_when_no_live_running_and_this_job_is_the_earliest_pending
 def test_u2b_a_tie_on_created_at_is_broken_by_job_id(tmp_path):
     same = _iso(time.time())
     _register_as(tmp_path, "aaaa0001", created_at=same)
-    _register_as(tmp_path, "aaaa0002", created_at=same)
+    _register_as(tmp_path, "aaaa0002", created_at=same, dispatch_wait_at=same)   # a live waiter
     assert decide.wait_open_jobs(_ns(tmp_path, "aaaa0001")) == "clear"
     assert decide.wait_open_jobs(_ns(tmp_path, "aaaa0002")) == "busy aaaa0001"
 
 
+# review 5a09a13f F-A: a live pending record nobody signals on is one its
+# producer injected without a waiter (create --onboard, a job sent by hand);
+# the prompt is in the pane, so it holds the session - never a FIFO peer that
+# a lower job id in the same second, or an earlier second, could pass
+
+@pytest.mark.parametrize("onboarding,waiter", [("ffffffff", "00000001"), ("00000001", "ffffffff")])
+def test_u2h_an_injected_record_holds_the_session_whatever_its_place_in_the_fifo(tmp_path, onboarding, waiter):
+    same = _iso(time.time())
+    _register_as(tmp_path, onboarding, created_at=same)                 # unsignalled, ack 180: live
+    _register_as(tmp_path, waiter, created_at=same)
+    assert decide.wait_open_jobs(_ns(tmp_path, waiter)) == f"busy {onboarding}"
+    assert "dispatch_admitted_token" not in _rec(tmp_path, waiter) and "dispatch_wait_at" in _rec(tmp_path, waiter)
+    assert "dispatch_wait_at" not in _rec(tmp_path, onboarding)
+    # registered after the waiter (which was still in its preflight): the same
+    _edit(tmp_path, onboarding, created_at=_iso(_at(same) + 1))
+    assert decide.wait_open_jobs(_ns(tmp_path, waiter)) == f"busy {onboarding}"
+    # control: the same record with a waiter's signal on it is a FIFO peer
+    _edit(tmp_path, onboarding, created_at=same, dispatch_wait_at=same)
+    assert decide.wait_open_jobs(_ns(tmp_path, waiter)) == ("clear" if waiter < onboarding else f"busy {onboarding}")
+
+
 def test_u2c_a_dead_waiter_is_ignored_and_reported(tmp_path, capsys):
     b = _register(tmp_path, ack=5, created_at=_iso(time.time() - 60), dispatch_wait_at=_iso(time.time() - WINDOW - 1))
     me = _register(tmp_path)
@@ -473,11 +496,13 @@ def test_u4_open_jobs_prints_live_and_stale(tmp_path):
     a = _register(tmp_path, status="running")
     _event(tmp_path, a, time.time())
     b = _register(tmp_path, created_at=_iso(time.time() - 1000))
+    c = _register(tmp_path)                                  # within its ack budget, no waiter on it
     me = _register(tmp_path)
     res = _cli(tmp_path, "open-jobs", "--job", me, "--agent-session", "herdr:s", "--registry-dir", str(tmp_path))
     assert res.returncode == 0, res.stderr
     assert f"{a}  running" in res.stdout
     assert f"{b}  stale     pending, no dispatch signal and no started within 180s" in res.stdout
+    assert f"{c}  injected" in res.stdout
 
 
 def _hold_pids(jid):

tests/test_issue50_dispatch_herdr.py

@@ -19,6 +19,7 @@ so the herdr idle wait stays and the registry wait runs before it.
 from __future__ import annotations
 
 import calendar
+import fcntl
 import json
 import os
 import re
@@ -522,15 +523,29 @@ def _onboarding(box: Box, ack: int) -> str:
 
 
 def test_c10_a_pending_onboarding_within_its_ack_budget_blocks_the_session_past_the_signal_window(box):
+    # review 5a09a13f F-A: the onboarding and the first job are registered in
+    # the same second (create registers, then injects; the job's wrapper
+    # registers a moment later), where the FIFO's (created_at, job_id) once
+    # let a lower id pass the injected onboarding; the second job comes a
+    # different second
+    while time.time() % 1 > 0.05:
+        time.sleep(0.005)
     t0 = time.time()
-    a = _onboarding(box, 180)
+    a = box.register(ack_timeout_sec=180)
     known = box.job_ids()
     for label in ("before", "after"):
         if label == "after":
             time.sleep(max(0.0, t0 + 31.5 - time.time()))       # A is now older than the signal window
         proc = box.submit(prompt="work " + label, MAM_DISPATCH_WAIT_S="3")
+        if label == "before":
+            prompt = box.herdr("agent", "prompt", SESSION, "Onboarding " + a)
+            assert prompt.returncode == 0, prompt.stdout + prompt.stderr
         b = box.wait_new_job(known)
         known.add(b)
+        print(label, "created", a, box.record(a)["created_at"], b, box.record(b)["created_at"],
+              "registered at +%.2fs" % (time.time() - t0))
+        if label == "before":
+            assert box.record(b)["created_at"] == box.record(a)["created_at"], "the same-second tie this exercises"
         rc, out, err = box.finish(proc)
         assert rc == 5, (label, out + err)
         rec = box.record(b)
@@ -727,6 +742,49 @@ def test_a3_three_concurrent_creates_in_one_folder_take_distinct_panes(local_mqt
         _teardown(b)
 
 
+def test_s2_an_ambient_and_a_named_call_share_the_servers_pane_claim():
+    """review e8e471ff R1: a call with the ambient target - no -L, HERDR_SESSION_NAME
+    empty or `default` - from a pane of server S is answered by S (the pane's
+    HERDR_SESSION / HERDR_SOCKET_PATH), so it claims under S's lock, the one a
+    call naming S takes: held, both wait; racing, they take distinct panes."""
+    b = _make_box(f"t50-{uuid.uuid4().hex[:8]}")
+    ambient = dict(HERDR_SESSION_NAME="default", HERDR_SESSION=b.sess,
+                   HERDR_SOCKET_PATH=str(b.home / ".config/herdr/sessions" / b.sess / "herdr.sock"))
+    new_session = 'herdr new-session -d -s {name} -c "$WORKSPACE_ROOT" "claude --dangerously-skip-permissions"'
+    try:
+        assert b.sh("herdr agent list").returncode == 0      # the server is up before the race
+        lock = b.home / ".local/state/mam/pane-lock" / f"{b.sess}.lock"
+        lock.parent.mkdir(parents=True, exist_ok=True)
+        with lock.open("a") as held:
+            fcntl.flock(held, fcntl.LOCK_EX)
+            for env in ({}, ambient):
+                res = b.sh(new_session.format(name="t50-held-creator-claude"), MAM_PANE_CLAIM_WAIT_S="1", **env)
+                assert res.returncode == 1 and "another pane claim" in res.stderr, (env, res.stdout, res.stderr)
+            assert json.loads(b.herdr("agent", "list").stdout)["result"]["agents"] == []
+        _hold_pane_creation(b, 8)
+        procs = []
+        for name, env in (("t50-named-creator-claude", {}), ("t50-ambient-creator-claude", ambient)):
+            if procs:
+                time.sleep(2)
+            out = tempfile.TemporaryFile("w+", dir=str(b.home))
+            err = tempfile.TemporaryFile("w+", dir=str(b.home))
+            procs.append((name, subprocess.Popen(["bash", "-c", f'source "{SKILLS}/lib.sh"\n' + new_session.format(name=name)],
+                                                 stdout=out, stderr=err, text=True, cwd=str(b.ctl), env=b.env(**env)), out, err))
+        outcome = {}
+        for name, proc, out, err in procs:
+            rc = proc.wait(timeout=120)
+            out.seek(0); err.seek(0)
+            outcome[name] = (rc, out.read(), err.read())
+        assert all(o[0] == 0 for o in outcome.values()), {n: (o[0], o[2][-800:]) for n, o in outcome.items()}
+        assert "agent_pane_busy" not in "".join(o[1] + o[2] for o in outcome.values())
+        panes = _agent_panes(b)
+        assert sorted(panes) == sorted(n for n, *_ in procs), panes
+        assert len({p for p, _c in panes.values()}) == 2, ("two agents on one pane", panes)
+        assert all(Path(c).resolve() == b.ctl.resolve() for _p, c in panes.values()), panes
+    finally:
+        _teardown(b)
+
+
 def test_s_three_concurrent_new_sessions_in_one_folder_take_distinct_panes():
     """The shim alone, no create around it: three `new-session` into one cwd on
     one running server at once. Before the pane claim was serialised, two of

tests/test_issue50_pane_lock.py

@@ -55,6 +55,31 @@ def test_p1_the_lock_file_is_per_server_under_the_sessions_home(tmp_path):
     assert res.stdout.strip() == pane_lock.lock_path("t50-x", env), res.stderr
 
 
+# review e8e471ff R1: the ambient target (no -L, HERDR_SESSION_NAME empty or
+# `default`) is answered by the server of the pane the caller runs in - the
+# pane's HERDR_SESSION / HERDR_SOCKET_PATH say which - so that is the lock;
+# only outside a pane is it the default server's
+
+def test_p1b_the_ambient_target_locks_the_callers_server(tmp_path):
+    home = {"HOME": str(tmp_path)}
+    sock = {"HERDR_SOCKET_PATH": str(tmp_path / ".config/herdr/sessions/t50-x/herdr.sock")}
+    named = pane_lock.lock_path("t50-x", home)
+    for ambient in ("", "default", None):
+        assert pane_lock.lock_path(ambient, {**home, **sock}) == named, ambient
+        assert pane_lock.lock_path(ambient, {**home, "HERDR_SESSION": "t50-x"}) == named, ambient
+        assert pane_lock.lock_path(ambient, {**home, "HERDR_SESSION": "t50-x",          # HERDR_SESSION first
+                                             "HERDR_SOCKET_PATH": str(tmp_path / ".config/herdr/sessions/t50-y/herdr.sock")}) == named
+        assert pane_lock.lock_path(ambient, {**home, "HERDR_SOCKET_PATH": str(tmp_path / ".config/herdr/herdr.sock")}) \
+            == pane_lock.lock_path("default", home) == str(tmp_path / ".local/state/mam/pane-lock/default.lock")
+        assert pane_lock.lock_path(ambient, {**home, "HERDR_SOCKET_PATH": "/elsewhere/herdr.sock"}).endswith("/default.lock")
+        assert pane_lock.lock_path(ambient, home).endswith("/default.lock")
+    assert pane_lock.lock_path("t50-y", {**home, **sock}) != named, "a named target is that server's, wherever it is called from"
+    outside = {k: v for k, v in os.environ.items() if not k.startswith("HERDR_")}   # this test may run in a pane
+    res = subprocess.run([sys.executable, "-m", "lib_py.pane_lock", "path", "--session", ""], capture_output=True, text=True,
+                         env=dict(outside, PYTHONPATH=str(SKILLS), HOME=str(tmp_path), **sock), timeout=60)
+    assert res.stdout.strip() == named, res.stderr
+
+
 def test_p2_a_free_lock_is_taken_at_once_and_a_held_one_times_out(tmp_path):
     lock = tmp_path / "s.lock"
     t0 = time.time()