A MAM script often runs inside one herdr server's pane (the orchestrator's)
while targeting another (the isolated MAM server). The pane exports
HERDR_WORKSPACE_ID, HERDR_PANE_ID and HERDR_TAB_ID, and those ids only mean
something on the server that issued them. They reached the scope filters as a
foreign workspace, whose fail-closed miss (ISSUE-3 / F-2b) reports a live
session as absent: has-session, kill-session, agent prompt and the delegate-job
preflight all answered "no such session". Reproduced on Linux and macOS in the
#23 comments, worked around until now with `env -u` at every call site.
mam_herdr drops the three ids for a call aimed at a named server other than the
caller's own. Scope then falls back to .mam/herdr_workspace_id and finally to
server-global, which is what _herdr_ws_scope already does. `default` is not a
crossing: it is the sentinel for "pass no session flag", so herdr answers on
the ambient server, which for a caller in a pane is that caller's own. A caller
outside any pane keeps an exported scope, so H-18/H-21/H-23 keep their meaning.
The fix lives in mam_herdr, not in the shim heredoc: that heredoc is
materialised into $WORKSPACE_ROOT/.mam/shim/herdr, one file shared by every
checkout bound to a control plane and rewritten on every herdr call, so editing
it would put unreviewed code in the control root and let two checkouts
overwrite each other. S11 fixes that invariant.
lib_py/loop/watcher.py builds its own herdr argv and is the one path that does
not go through mam_herdr, so it applies the same rule via scoped_env.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
engine.transition is now the only writer of job status. It implements the target
table in state-transitions.md §3: claim, non-terminal metadata, explicit
terminals, idempotent re-receipt, refusal of conflicting or late signals with an
audit entry, stale-attempt rejection, and deadline timeout.
Two write paths become one. update_job_status merged fields unconditionally;
pick_pending hand-rolled a correct pending->running swap plus its own audit
mirror. Neither was wrong alone, but a rule added to one silently missed the
other, which is the shape that produced the phase 1 transport bugs. Both keep
their signatures and their preserved legacy bodies behind MAM_ENGINE_CAS=0.
A merged `status` value is routed to the request that owns it, so a raw field
write can no longer slip past the table. Getting that wrong first was caught by
the characterization tests: a metadata merge was overwriting the caller's status
with the pre-merge value.
Lock discipline is now enforced, not described. The lock covers a decision and
one record write; audit mirroring is queued and flushed after release, carrying a
monotonic transition_seq so ordering survives the move. A test watches for
subprocess, socket and sleep calls while the lock is held and asserts none.
Structural correction to my own plan, caught by a phase 1 guard: the plan put the
engine in lib_py/loop, but delegation would then have had to import a sibling,
which is exactly what mixes trees under a frozen loop. The engine belongs with
the registry writers, so it lives in lib_py/delegation and loop consumes it.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UrDNJkHmm18uu7n7JwV5Qd
GodopuandClaude Opus 5