diff --git a/agents/sage/work/s4-follow-up/trackers-boot.test.mjs b/agents/sage/work/s4-follow-up/trackers-boot.test.mjs
new file mode 100644
index 00000000..b7710013
--- /dev/null
+++ b/agents/sage/work/s4-follow-up/trackers-boot.test.mjs
@@ -0,0 +1,66 @@
+// Sage's row 39 gate check, not part of the candidate: the S4 host boots the
+// S3 adapter through the real process.mjs when bootConfig emits trackers.
+import { test } from "node:test";
+import assert from "node:assert/strict";
+import { chmodSync, mkdirSync, writeFileSync } from "node:fs";
+import { join } from "node:path";
+import { Client } from "../../bus/src/client.mjs";
+import { bootConfig, loadSystem } from "../src/config.mjs";
+import { startHost, startTimeOf } from "../src/host.mjs";
+import { writeJson } from "../../business/tests/helpers.mjs";
+import { FakeVikunja } from "../../tasks/src/fake.mjs";
+import { SCOPES } from "../../tasks/tests/world.mjs";
+import { fixture, tmp } from "./helpers.mjs";
+
+test("bootConfig trackers reach the S3 adapter in the real broker child, which goes ready against a fake Vikunja", async (t) => {
+  const root = tmp(t);
+  const fake = new FakeVikunja();
+  const srv = await fake.listen();
+  t.after(() => srv.close());
+  const owner = fake.user("svc-acme");
+  const bots = {};
+  for (const r of ["sync", "pm", "cto", "coder", "reviewer"]) bots[r] = fake.user(`bot-acme-${r}`, { owner });
+  const project = fake.project("Acme", owner);
+  for (const r of ["pm", "cto", "coder", "reviewer"]) fake.share(project, bots[r], 1);
+  fake.share(project, bots.sync, 0);
+  fake.install(project);
+
+  const f = fixture(root, "acme", (doc) => {
+    doc.vars["tracker.baseUrl"] = srv.url;
+    doc.tracker.sync.botId = bots.sync;
+    for (const r of Object.keys(doc.roles)) doc.roles[r].tracker.botId = bots[r];
+    return doc;
+  });
+  const put = (file, token) => {
+    writeFileSync(file, token + "\n");
+    chmodSync(file, 0o600);
+  };
+  put(f.doc.tracker.sync.credentials.vikunja.file, fake.token(bots.sync, SCOPES.sync));
+  for (const r of Object.keys(f.doc.roles)) put(f.doc.roles[r].credentials.vikunja.file, fake.token(bots[r], r === "pm" ? SCOPES.pm : SCOPES.worker));
+  writeJson(join(root, "project", ".mosaic", "project.json"), { projectVersion: 1, id: "stack", vars: { "tracker.project": project } });
+
+  mkdirSync(f.dataRoot, { recursive: true, mode: 0o700 });
+  const boot = bootConfig({ system: loadSystem({ env: f.env }), businessId: "acme", env: f.env });
+  assert.deepEqual(boot.trackers, { acme: { baseUrl: srv.url, project, pollSeconds: 60, reconcileMinutes: 60 } });
+  const host = await startHost({ boot, business: "acme", log: () => {} });
+  t.after(() => host.close(0));
+
+  const launch = await host.bindLaunch({ business: "acme", role: "pm", run: "pm-run", harness: "pi", pid: process.pid, startTime: startTimeOf(process.pid) });
+  const pm = new Client({ path: host.path, cap: launch.cap });
+  await pm.call("role.claim");
+  let code;
+  const end = Date.now() + 15000;
+  do {
+    code = await pm.call("task.close", {}).then(() => "ok", (e) => e.code);
+    if (code !== "tracker-starting") break;
+    await new Promise((r) => setTimeout(r, 100));
+  } while (Date.now() < end);
+  console.log(`task.close {} answered: ${code}; fake saw ${fake.requests.length} requests, first ${fake.requests.slice(0, 3).map((r) => `${r.method} ${r.path} ${r.status}`).join(", ")}`);
+  assert.ok(fake.requests.some((r) => r.path === "/info"), "the adapter called the fake");
+  assert.doesNotMatch(code, /^(tracker-|credential-|scope-too-broad)/, "the adapter is ready, so the verb fails on its own arguments");
+  const before = fake.requests.length;
+  const missing = await pm.call("task.close", { task_ref: `vikunja:${project}/999`, verdict: "gate check" }).then(() => "ok", (e) => e.code);
+  console.log(`task.close on a missing task answered: ${missing}; it made ${fake.requests.slice(before).map((r) => `${r.method} ${r.path} ${r.status}`).join(", ")}`);
+  assert.ok(fake.requests.length > before, "a well-formed verb reached Vikunja through the adapter");
+  assert.equal(await host.close(0), 0);
+});
diff --git a/docs/plans/2026-09-26_lead-decisions.md b/docs/plans/2026-09-26_lead-decisions.md
index c9980be3..5b782fce 100644
--- a/docs/plans/2026-09-26_lead-decisions.md
+++ b/docs/plans/2026-09-26_lead-decisions.md
@@ -1396,3 +1396,39 @@ which stay with him. Each item names who decided it and what happened.
       - Tests for mutants M22 to M24, M26 and M29.
     - Follow-ups, not round 2: F2 (a refused DM retries every 30 min with
       no limit) and J4 (loose types in confirmed lines).
+
+72. **S4 follow-up row and the conversation cohort row (2026-10-09).**
+    Source: Filbert's and Darkwing's round 1 and round 2 reviews of
+    #1521, the row 38 and row 39 gate runs, and my probe of the cohort
+    failures. Brief: `docs/plans/2026-10-09_s4-follow-up-and-cohort.md`.
+    - The items decision 71 and the reviews held for later go in one
+      row for Rocko: F2, J4, the N2, N4, N5 and M28 mutants, the reader
+      capability check, the host's `broker.connected` guard, clearer
+      journal errors, the `mkdir -m 0700` line in the install message,
+      the flaky discord lock test, and my trackers boot test. Filbert
+      and Darkwing review, since the row changes the DM path again.
+    - F2 ruling. Retrying `unknown` outcomes (network, 5xx or 429)
+      stays unlimited at the 30-minute cap. A missed blocking decision
+      still costs more than a duplicate DM. A definite refusal is a
+      4xx other than 429. Five of them for one decision stop that DM:
+      one `gave-up` line, one log line, and the digest says "DM refused,
+      not retried". The count comes from the journal, so a restart
+      doesn't start it over. Five is enough to ride out a binding typo
+      fixed within a few hours. Fewer would give up on a fixable
+      mistake, and more only lengthens the journal.
+    - J4 ruling. Opening the journal type-checks confirmed lines and
+      refuses a bad one with exit 3, the same as a malformed line.
+      Today's lookups go by string, so the loose types do no harm yet.
+      But a journal that loads anything stops being evidence.
+    - The packet's BUILD.md M28 line stays as approved. BUILD-LOG holds
+      the correction. The bus shim's `spawnSync` timeout (Filbert round
+      1, note 8) stays out of scope until a bus row needs it.
+    - Cohort row. K1, K3 and K10 fail on this host in isolation. All
+      three use an `ignoreTerm` child under a systemd user scope. That
+      child survives SIGTERM outside a scope. They passed on 2026-10-05,
+      the package hasn't changed since 243e153c, and no systemd, kernel
+      or node upgrade landed after 2026-09-03. Darkwing owns the
+      diagnosis and fix, and Dewey reviews. Dewey wrote CHAT-03 I1, and
+      row 40 gates on this suite. If the cause is the host's systemd
+      configuration, the row reports it and stops. That's Jason's
+      machine.
diff --git a/docs/plans/2026-10-09_s4-follow-up-and-cohort.md b/docs/plans/2026-10-09_s4-follow-up-and-cohort.md
new file mode 100644
index 00000000..5342a008
--- /dev/null
+++ b/docs/plans/2026-10-09_s4-follow-up-and-cohort.md
@@ -0,0 +1,207 @@
+# S4 follow-up and the conversation cohort failures (2026-10-09)
+
+Status: written by Sage, lead, under lead decision 72. It follows
+`docs/plans/BRIEF-TEMPLATE.md` and amends no section of the slice 1
+brief. Two rows, one heading each.
+
+## S4 follow-up: notifier retry limit, journal types and the round 2 test gaps
+
+### Problem
+
+Row 39 (S4, #1521) landed as 2f5303c1 with items the reviews left for
+later. They are listed below.
+
+- **F2.** `packages/cli/src/notifier.mjs` retries a refused DM with
+  backoff capped at 30 minutes and no attempt limit. It also appends a
+  journal line on every attempt, so a DM that Discord refuses for good
+  keeps sending and grows `sent.jsonl` by 48 lines a day.
+- **J4.** Confirmed journal lines with loose types load. Examples are a
+  numeric `decision` and a digest line with no `day` (Filbert round 1,
+  note 4).
+- **Surviving mutants.** N2, N4 and N5 survive (Filbert round 2, notes
+  4 to 6):
+  - N2: the directory check uses `statSync` instead of `lstatSync`.
+  - N4: `append` opens without `O_NOFOLLOW`.
+  - N5: `watchChildren`'s early check ignores `signalCode`.
+- **M28.** It survived. No test covers the host's "a bus host already
+  runs" refusal. The BUILD-LOG entry for row 39 records the correction.
+- **Reader capability.** host.test checks that the launch capability
+  stays out of `/proc/<pid>/cmdline` and `environ`. It doesn't check
+  the reader capability sent to the notifier (Filbert round 1, note 5).
+- **Host shutdown path.** `packages/cli/src/host.mjs:144` and `:150` call
+  `broker.send({ op: "close" })` without checking `broker.connected`.
+  Against a broker that already died, that throws `ERR_IPC_CHANNEL_CLOSED`.
+- **Test cleanup.** The host test "a notifier that dies" has no
+  `t.after` close, so a failure leaves children running.
+- **Raw errors.**
+  - A read-only or 0500 journal directory surfaces a raw `EACCES`, not a
+    `CliError` (Filbert round 2, note 10; Darkwing round 2, note 2).
+  - A symlinked directory refuses with "must be mode 0700 and owned by
+    this user". That is true, but it doesn't name the link (Filbert
+    round 2, note 9).
+- **Install message.** `scripts/bus-service.sh` tells the operator to
+  write `notify.json` but never says to create the directory 0700
+  (Darkwing round 2, note 1). An operator who runs a plain `mkdir -p`
+  gets a host that refuses with exit 3.
+- **Flaky discord test.** `packages/discord/tests/journal.test.mjs:120`
+  publishes pid `2 ** 22 - 7` and expects `ownerState` to be `dead`. On
+  a host where that pid is live, it reads `unknown`. That was the only
+  failure in the row 39 M28 mutant run.
+- **Trackers boot test.** The combined-tree check that S4's host
+  boots S3's tracker adapter from config ran from scratch at the row 39
+  gate and isn't in the suite. It is at
+  `agents/sage/work/s4-follow-up/trackers-boot.test.mjs`. Its relative
+  imports assume `packages/cli/tests/`.
+
+### Owner and reviewer
+
+- Owner: rocko.
+- Reviewers: filbert, and darkwing because the row changes the DM path
+  and the discord package's tests.
+
+### Files owned
+
+- `packages/cli/src/notifier.mjs`, `packages/cli/src/host.mjs`
+- `packages/cli/tests/*`, including the new
+  `packages/cli/tests/trackers-boot.test.mjs`
+- `packages/cli/README.md`
+- `packages/discord/tests/journal.test.mjs`
+- `scripts/bus-service.sh`
+- `docs/TOOLS.md`, only if a command's output changes
+- `agents/rocko/work/s4-follow-up/` (the packet)
+
+### What ships
+
+1. **F2, under decision 72.**
+   - A DM refused with an HTTP 4xx other than 429 is a definite
+     refusal. After 5 definite refusals for one decision, the notifier
+     stops sending that DM. It appends one `gave-up` line and logs it
+     once.
+   - The count comes from the journal, so a restart doesn't reset it.
+   - The digest lists that decision as "DM refused, not retried".
+   - An `unknown` outcome (network, 5xx or 429) keeps the capped
+     backoff with no limit. Under decision 70, a duplicate DM is
+     cheaper than a missed one.
+   - The `outcome` comment in `notifier.mjs` and the README name the
+     new value.
+2. **J4.**
+   - Opening the journal type-checks every complete line:
+     - `at`: ISO string
+     - `kind`: `dm` or `digest`
+     - `decision`: string, required for `dm`
+     - `day`: `YYYY-MM-DD` string, required for `digest`
+     - `outcome`: one of the four values
+     - `messageId`: string or null
+     - `status`: integer when present
+   - A line that fails refuses with exit 3, as a malformed line does
+     today. The decision 71 torn-tail rule is unchanged.
+3. **Tests.**
+   - Tests that kill N2, N4, N5 and M28.
+   - A reader-capability exposure check in host.test.
+   - `t.after` cleanup in "a notifier that dies".
+4. **Host shutdown.** Guard both `broker.send` calls with
+   `broker.connected`.
+5. **Errors.**
+   - A journal directory the notifier can't write refuses with a
+     `CliError`, exit 3, naming the path.
+   - A symlinked directory refuses with a message that says it is a
+     link.
+6. **Install message.** `bus-service.sh`'s install message adds
+   `mkdir -m 0700 -p <dataRoot>/notify/<business>`.
+7. **Discord test.** `journal.test.mjs:120` uses a pid that is
+   provably not running, for example a reaped child's pid checked with
+   `kill(pid, 0)`. It must not depend on a fixed number.
+8. **Trackers boot test.** Move it into `packages/cli/tests/` as
+   written, adjusting only its imports if needed.
+9. **Suites.** cli, discord, bus and tasks node suites,
+   `test-discord.sh` and every `test-*.sh` green. Include a mutant
+   table for N2, N4, N5, M28 and the F2 limit.
+
+### Out of scope
+
+- Round 1 note 8, the `spawnSync` timeout in `human-cli`. It lives in
+  the bus shim. It goes to a bus row if it ever bites.
+- The live DM run. That is Sage's, at Jason's go, under decision 70.
+- The packet `agents/rocko/work/slice1-s4/BUILD.md`. It stays as
+  approved, and BUILD-LOG holds the M28 correction.
+
+### Gate
+
+- Filbert and Darkwing approve on the row's issue.
+- Sage reruns the integration gate on a git worktree with the candidate
+  applied: every node package suite and every `scripts/test-*.sh`.
+  Expect zero failures, except the three conversation cases owned by
+  the next row, and only until that row lands.
+
+## Conversation cohort: K1, K3 and K10 fail on the scope fixtures
+
+### Problem
+
+`packages/conversation/tests/cohort.test.mjs` fails K1, K3 and K10 on
+this host.
+
+- **Where it fails.** It failed at the row 38 and row 39 gates, and
+  again on the canonical tree run alone on 2026-10-09 at 12:50Z. That
+  run was `node --test --test-name-pattern='^K(1|3|10):'`: 0 pass,
+  3 fail.
+- **The assertions.**
+  - K1: "the escaped child is a listed member".
+  - K3: "the member ignored TERM". The child is dead after TERM.
+  - K10: "the member is alive across the crash".
+- **What all three share.** Each spawns a tool child with `ignoreTerm`
+  under a systemd user scope (`packages/conversation/tests/fake-pi.mjs`,
+  `spawnChild`).
+- **Outside a scope.** The same child spawned outside a scope survives
+  SIGTERM (Sage's probe, 2026-10-09).
+- **What passes.** K2 (process-group fallback), K11 to K15 and the
+  in-process cases pass.
+- **History.** All three passed at the row 44 gate on 2026-10-05. The
+  package hasn't changed since 243e153c (2026-10-04).
+- **Not a package upgrade.** The host's last relevant upgrades were
+  systemd 261.2, kernel 7.2.2 and node 26.8.1, all on 2026-09-03,
+  before that gate. So something else on the host or in the user
+  manager changed.
+- **Who it blocks.** Row 40 (S5) gates on the conversation suite being
+  green.
+
+### Owner and reviewer
+
+- Owner: darkwing.
+- Reviewer: dewey, who wrote CHAT-03 I1 and owns row 40, which needs
+  this suite green.
+
+### Files owned
+
+- `packages/conversation/tests/*`
+- `packages/conversation/src/cohort.mjs`, only if the diagnosis shows a
+  real defect in the cohort proof rather than in the fixture
+- `agents/darkwing/work/cohort-k1/` (the packet: diagnosis, probes and
+  receipts)
+
+### What ships
+
+1. **Diagnosis.** Say why an `ignoreTerm` child in the scope dies or
+   leaves the member list early. Back it with receipts:
+   - `systemctl --user show` on the scope
+   - `cgroup.procs` before and after TERM
+   - the child's exit signal
+2. **Fixture defect.** If it is a fixture or environment defect, fix
+   the fixture so the three cases test what their names say on this
+   host. Never weaken an assertion to pass.
+3. **Code defect.** If it is a defect in `cohort.mjs`, fix it. A
+   `stopped` proof must stay impossible while a member lives.
+4. **Suites.** conversation and webui suites green on this host, and
+   K1, K3 and K10 green in 3 consecutive isolated runs.
+
+### Out of scope
+
+- Changes to the host's systemd configuration or user manager. If the
+  diagnosis points there, report it and stop; that's Jason's machine.
+- Any CHAT-03 behavior beyond the stop and cohort proof.
+
+### Gate
+
+- Dewey approves on the row's issue.
+- Sage reruns the conversation suite and the three cases in isolation
+  on a worktree with the candidate applied. Expect 152/152, then 3/3
+  three times.