docs(process): framing revision 4 — record what implementing found

Not a new design round. Every bet resolved, and one acceptance turned
out to be satisfiable vacuously.

Acceptance 2's in-drain clause said "the live descendant's named late
output absent" without saying how the descendant stays live. It does
not, by default: `poll_one` TERMs the whole group on leader exit. The
first fixture's marker was therefore absent on both paths, and the pin
would have stayed green with the collapse fixed.

Bets 1 and 2 hold — every site took a directed outcome without
restructuring, and every consequence is reachable, so the lane does not
shrink. Bet 3 resolves the shutdown coupling as real and measured. Bet
4 is falsified exactly as its own clause anticipated: `ProcessEvent` is
keyed by `ProcessId` while the ledger is keyed by pgid and is
deliberately independent of managed records, every production consumer
polls per known id, and `take_all_events` has no production consumer at
all. Q#RL3 is answered accordingly and reporting is parked as its own
lane.

Also records the four sites and the two reusable lessons in
`docs/agent-handoff.md` — that a seam for a background loop has to be
directed, and that an absence assertion is only as good as its
fixture's ability to produce the thing.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Lv428Fth9LRtffwJSsqH7T

docs/active-work.md

@@ -333,14 +333,32 @@ compatible.
     githubsucks/test-ambient-config-isolation
   ```
 
-## Reap-ledger silent failures — FRAMING OPEN, revision 3
+## Reap-ledger silent failures — IMPLEMENTED, PR OPEN
 
 - **Branch `reap-ledger-silent-failures`**, worktree
   `../pmacs-reap-ledger`, based on `githubsucks/main` @ `22df6ab`.
-  **Framing only; no code, no PR yet.**
-  `docs/reap-ledger-silent-failures-framing.md`, revision 3; two review
-  rounds closed (round 1: three blocking, two major; round 2: two
-  blocking, two major; all accepted).
+  `docs/reap-ledger-silent-failures-framing.md`, **revision 4**;
+  approved at revision 3 after two review rounds (round 1: three
+  blocking, two major; round 2: two blocking, two major; all accepted).
+  Revision 4 records implementation findings, not a new design round.
+- **All four bets resolved.** Bet 1 (every site takes a directed
+  outcome) and Bet 2 (every consequence is reachable) hold. **Bet 3
+  resolves the shutdown coupling as real and measured** — under 500ms
+  with a failed force-kill plus an errored probe, versus the full 2s
+  bound with only the force-kill failing. **Bet 4 is falsified: no
+  reporting channel exists**, so reporting becomes its own lane.
+- **The in-drain pin's first fixture was vacuous, and the bite caught
+  it.** `poll_one` TERMs the group on leader exit, so an untrapped
+  descendant died before writing its late marker — absent on *both*
+  paths. With the seam reverted the pin failed only the consumed-plan
+  check, never the content assertion. Fixed with `trap '' TERM` behind
+  the readiness gate.
+- **Gates: 10/10 green** on the pushed tree, all five bootstrap-storage
+  variables controlled — fmt, diff-check, clippy, `--lib` (1888),
+  `--lib --features crdt` (2073), compile-mode (67), copy-mode in both
+  feature configurations (18/19), M4 with the basedpyright skip (149),
+  required GPU (221). The five new process pins ran **15/15** as a
+  repetition set, since supervisor tests are load-sensitive.
 - **Unparked from PR #200's §5.** #200 retired the premise that
   justified the ledger's leniency and deliberately changed no
   disposition; this lane owns what it refused.

docs/agent-handoff.md

@@ -257,6 +257,61 @@ commands, read `docs/active-work.md` immediately after this file.
     disagree — and it still establishes no identity, because it is read
     inside the same read-then-act window and no portable mechanism closes
     that for a *group* (`pidfd` covers a process; macOS has neither).
+- **Reap-ledger silent failures — DIAGNOSTIC, in flight**
+  (`docs/reap-ledger-silent-failures-framing.md`). The lane #200's
+  framing §5 parked and its evidence unparked. **Four `kill(2)` results
+  are discarded in the group reap ledger**, and each discard has its own
+  consequence — three in the persistent ledger, one in the in-drain
+  twin:
+  - `tick_reap_ledger`'s probe cannot tell `ESRCH` (the group is gone —
+    correct) from any other errno (we could not ask — not correct), and
+    `retain` deletes the entry either way, cancelling escalation.
+  - The deadline escalation sets `killed = true` whether or not the
+    `SIGKILL` landed, so a failed one is **never retried by anything**.
+  - `shutdown()`'s force-kill does the same, on the path written
+    specifically to stop a leak at editor exit.
+  - `final_drain_runtime`'s twin collapses every errno into "dead",
+    which quiesces the drain and **cancels the readers** — truncated
+    output rather than a leaked process, and terminal for that drain
+    where a later tick could revisit the ledger.
+  - **None of the four has been observed to fire.** #200's evidence is an
+    explicit `SIGTERM` failing in `signal()`, not any ledger call. What
+    it retires is the *reason* ("EPERM cannot happen for our own
+    children"), not the behaviour.
+  - **`shutdown()`'s loop exit depends on the silent drop, and this is
+    now measured.** It runs while `any_running() || !reap_ledger.is_empty()`,
+    so an early exit needs the ledger empty **and** no live managed
+    record — the leader-exited-survivor case the ledger exists to serve.
+    With a failed force-kill followed by an errored probe it exits in
+    under 500ms instead of holding its 2s bound, having concluded
+    cleanup finished because the probe failed. Making the probe strict
+    without touching the loop converts that silent early exit into a
+    guaranteed 2s stall at every editor exit that hits it: **the two
+    cannot be changed independently.**
+  - **There is no channel for a background tick to report on.**
+    `ProcessEvent` is keyed by `ProcessId`, while the ledger is keyed by
+    pgid and is deliberately independent of managed records, so in the
+    case that matters there is no id to attribute to. Every production
+    consumer polls `take_events(id)` per known id; `take_all_events`
+    would sidestep the keying but **has no production consumer at all**
+    (two test call sites only). `pmacs.error` is dead. Reporting is
+    therefore its own lane, as the framing's Bet 4 anticipated.
+  - **A test seam for a background loop has to be directed.**
+    `shutdown()` signals every managed process before it reaches its
+    ledger force-kill, so one undirected "next kill fails" slot is eaten
+    by the wrong call and the test passes while proving nothing. The
+    persistent sites take a FIFO each (the coupling pin needs two
+    outcomes pending at once); the in-drain site needs one outcome that
+    **repeats for a whole drain**, because a one-shot is consumed by the
+    next 1ms probe and can never survive the 50ms window `quiesced`
+    requires.
+  - **An absence assertion needs a fixture that could have produced the
+    thing.** The in-drain pin's first fixture had no `trap '' TERM`, so
+    `poll_one`'s leader-exit group TERM killed the descendant before it
+    wrote its late marker: the marker was absent on *both* paths and the
+    pin would have stayed green with the collapse fixed. The bite caught
+    it — the reverted seam failed only the consumed-plan check, not the
+    content assertion. That is what the consumed-plan check is for.
 - **Lean 4 arc (Arc 8) — stages 1, 2, 3a, 3b, 4a, 4b ALL LANDED**
   (`docs/lean4-mode-framing.md`; #160, #161, #167, #170, #179, #181). pmacs edits Lean 4: `arborium-lean` highlighting, a
   `lean4` major mode, `⟨⟩ ⦃⦄ ⟮⟯` pairs, and a `lake serve` language

docs/reap-ledger-silent-failures-framing.md

@@ -1,8 +1,9 @@
 # Framing — group cleanup fails silently at four sites
 
-**Revision 3.** Status: awaiting review round 3. Proposed lane:
+**Revision 4.** Status: **APPROVED at revision 3; implemented.** Lane
 `reap-ledger-silent-failures`, worktree `../pmacs-reap-ledger`, based on
-`githubsucks/main` @ `22df6ab` (a reading; re-measure at branch time).
+`githubsucks/main` @ `22df6ab`. Revision 4 records what implementation
+found; it is not a new design round.
 
 **Parked by PR #200's framing §5 and unparked by its evidence.** #200
 retired the premise that justified the ledger's leniency; it deliberately
@@ -10,6 +11,53 @@ changed no disposition, and said so. This lane owns what it refused.
 
 ## Revision history
 
+**Revision 3 → 4**, found **while implementing**, not a new design
+round. Every bet resolved; one acceptance turned out to be satisfiable
+vacuously.
+
+- **Acceptance 2's in-drain clause could be met by a vacuous fixture,
+  and was.** "The live descendant's named late output absent" says
+  nothing about how the descendant stays live — and `poll_one` sends
+  `SIGTERM` to the whole group on leader exit, so an untrapped
+  descendant dies before it can write. The marker was then absent on
+  *both* paths and the pin would have stayed green with the collapse
+  fixed. The bite is what caught it: with the seam reverted, the pin
+  failed only the consumed-plan check, never the content assertion. The
+  fixture now uses `trap '' TERM` behind `survivor_script`'s readiness
+  gate. **The lesson generalises past this pin: an absence assertion is
+  only as good as the fixture's ability to produce the thing.**
+- **Bet 1 holds.** All four sites took a directed outcome with no
+  restructuring. `final_drain_runtime` — the one §3 named as at risk,
+  being a free function — needed only a shared handle on the context it
+  already receives.
+- **Bet 2 holds, in the direction that keeps the lane.** All four
+  consequences are reachable; none was already foreclosed by an earlier
+  guard. The lane does not shrink.
+- **Bet 3 resolves: the coupling is real and measured.** With a failed
+  force-kill and an errored probe, `shutdown()` returns in **under
+  500ms** instead of holding its 2s bound, with the survivor alive. With
+  only the failed force-kill it burns the full bound. §1.3's warning
+  stands: making the probe strict without touching the loop converts a
+  silent early exit into a guaranteed 2s stall.
+- **Bet 4 is falsified, exactly as its own clause anticipated: no
+  channel exists.** `ProcessEvent` is keyed by `ProcessId` while the
+  ledger is keyed by pgid and is deliberately independent of managed
+  records, so in the leader-exited-survivor case there is no id to
+  attribute to. Every production consumer polls `take_events(id)` per
+  known id (`lua_bindings/mod.rs:8933`, `:10731`, `mcp.rs:361`).
+  `take_all_events` would sidestep the keying but **has no production
+  consumer at all** — its only two call sites are tests, despite a doc
+  comment naming a `*processes*` buffer. `pmacs.error` was already
+  known dead. **Reporting becomes its own lane** (§5), and this PR ships
+  instrumentation plus tests without it, which is what §7 said it would
+  do in this case.
+- **The in-drain `SIGKILL` is still unpinned**, as §1.2a promised. Its
+  `group_killed` flag stays local and the persistent ledger retries in
+  the same outer tick, so pinning the local non-retry still needs a
+  call-count assertion or a direct free-function test. Unchanged, and
+  restated here so a later reader does not mistake the shipped seam for
+  covering it.
+
 **Revision 2 → 3**, after review round 2 (two blocking, two major).
 All four accepted; all four verified in the code first.
 
@@ -271,10 +319,17 @@ noted so a red run on it is not mistaken for this lane's doing.*
   *Unknown. `killed = true` on a failed `SIGKILL` is clearly wrong as
   bookkeeping; what should replace it is a policy question, not an
   obvious fix.*
-- **Q#RL3** — How does a background tick report anything? *The ledger
-  emits no events and has no status channel. `pmacs.error` is defined
-  only by a test stub and is dead at 15 call sites, so it is not the
-  answer. This is the lane's real design question.*
+- **Q#RL3** — How does a background tick report anything? **ANSWERED at
+  revision 4: it cannot, today.** `ProcessEvent` is keyed by
+  `ProcessId`; the ledger is keyed by pgid and is deliberately
+  independent of managed records, so in the leader-exited-survivor case
+  — the one the mechanism exists for — there is no id to attribute to.
+  All three production consumers poll `take_events(id)` per known id
+  (`lua_bindings/mod.rs:8933`, `:10731`, `mcp.rs:361`).
+  `take_all_events` would sidestep the keying but has **no production
+  consumer**; its only call sites are two tests, notwithstanding a doc
+  comment naming a `*processes*` buffer. `pmacs.error` was already dead
+  at 15 sites. Reporting is therefore parked as its own lane (§5).
 - **Q#RL4** — Does the `shutdown()` loop need its own termination
   condition if (a) becomes strict? *Almost certainly (§1.3), and that
   coupling is why the two cannot be changed independently.*