diff --git a/agents/honker/work/queue-194/BUILD.md b/agents/honker/work/queue-194/BUILD.md
index 2cde30412..6e3568701 100644
--- a/agents/honker/work/queue-194/BUILD.md
+++ b/agents/honker/work/queue-194/BUILD.md
@@ -725,3 +725,33 @@ tokens are gone, but neither refusal says so. Only `credential-revoke-failed` ha
   re-checks under its lock); or run `beforeWrite` inside `writer.write` after the `:188` check; and in
   either case give `revision-conflict` and `outcome-unknown` text that says tokens may already be revoked
   when a revoke ran.
+
+### sage-1634: N1 fixed in b3 (2026-10-21T01:20Z)
+
+Sage ruled N1 a blocker for 194: it is the row's own code in files the row already changes. Option 1 is in.
+The section above stays as written; this entry supersedes its "no b3 change".
+
+- `business/src/instance-settings.mjs` `commit()`: before `beforeWrite`, compare the requested revision with
+  `writer.read(business).revision` and refuse `revision-conflict` on a difference, without calling
+  `beforeWrite`. It runs for every caller (add, set, veto, hire, fire, delete). Every caller already read the
+  file with `writer.read` (it validates), so a file that went invalid in between refuses `BusinessError`,
+  also before any revoke.
+- Fire reads its revision fresh (`:311`) in the same synchronous call, so it reaches a stale revision only
+  through another process writing between that read and `commit()`. No test makes that happen without an
+  injected writer; the check is the same line, and the delete test kills both mutants.
+- Test: bus `lifecycle-revoke.test.mjs` T21. A delete raised on revision R and taken; a credential issue for
+  rev-3 writes the file; the delete refuses `revision-conflict`. The business file's bytes and rev-2's
+  Credentials entry are unchanged, the vikunja token file is still there with its bytes, the store holds only
+  it, and the status reads valid.
+- Refusal text: `revision-conflict` says the file changed since that revision (CLI `instances.mjs` REASONS,
+  Console `serve.mjs` INSTANCE_REASONS). Neither says anything was revoked, so no change. The Console's
+  AGENT_REASONS has no entry for it.
+- Mutants for the slot: M76 drops the early check (T21 fails: the token file is removed); M77 moves it after
+  `beforeWrite` (T21 fails the same way, then refuses).
+- Runs, singly or whole as Sage asked: business whole 207 pass, bus whole 525 pass, seat whole 164 pass
+  (sandbox.test included), cli instances 14, cli lifecycle 16, webui agents 8, all 0 fail.
+
+Follow-up (option 2, not in b3): run `beforeWrite` inside `writer.write`, under its lock and after the
+`organization.mjs:188` check. Until then a window remains: a write landing between the early read and the
+writer's lock still lets a fire or delete revoke and then refuse `revision-conflict`, and an `outcome-unknown`
+after a revoke still doesn't say the tokens are gone.
diff --git a/packages/bus/tests/lifecycle-revoke.test.mjs b/packages/bus/tests/lifecycle-revoke.test.mjs
index 464885fe4..8b8c7ccec 100644
--- a/packages/bus/tests/lifecycle-revoke.test.mjs
+++ b/packages/bus/tests/lifecycle-revoke.test.mjs
@@ -142,3 +142,23 @@ test('T20 delete: with no entry in the running bus, a token file is cleared and
   assert.equal(f.bytes(), before);
   assert.deepEqual(f.status('coder'), { gitea: 'not-issued', vikunja: 'valid' });
 });
+
+test('T21 delete: a write between the raise and the take makes the delete refuse revision-conflict before it revokes anything', async (t) => {
+  const f = await setup(t);
+  f.ask('credentials.issue', { agent: 'rev-2', service: 'vikunja', token: TOKEN, date: '2099-01-01' });
+  const { request } = f.ask('instances.set', { revision: f.ask('instances').revision, instance: 'rev-2', op: 'delete' });
+  assert.equal(f.bus.lifecycleTake({ business: 'demo', request }).go, true);
+  // A write after the raise: the request's revision is now stale.
+  const raised = f.bytes();
+  f.ask('credentials.issue', { agent: 'rev-3', service: 'gitea', token: 'fake_other_token_9876543210', date: '2099-02-01' });
+  assert.ok(f.bytes() !== raised, 'the issue wrote the business file');
+  const before = f.bytes();
+  const entry = structuredClone(JSON.parse(before).roles['rev-2'].credentials);
+  assert.equal(f.code(() => f.bus.lifecycleDelete({ business: 'demo', request })), 'revision-conflict');
+  // Nothing revoked: the token stays issued, Credentials is unchanged and no store file is removed.
+  assert.equal(f.bytes(), before);
+  assert.deepEqual(JSON.parse(f.bytes()).roles['rev-2'].credentials, entry);
+  assert.equal(readFileSync(join(f.agentDir('rev-2'), 'vikunja'), 'utf8'), TOKEN + '\n');
+  assert.deepEqual(readdirSync(f.agentDir('rev-2')), ['vikunja']);
+  assert.deepEqual(f.status('rev-2'), { gitea: 'not-issued', vikunja: 'valid' });
+});
diff --git a/packages/business/src/instance-settings.mjs b/packages/business/src/instance-settings.mjs
index 3a8c6aeae..73364355f 100644
--- a/packages/business/src/instance-settings.mjs
+++ b/packages/business/src/instance-settings.mjs
@@ -367,6 +367,11 @@ export function instanceSettings({ dir, rolesDir, system, levels = () => null, r
         }
       }
     }
+    // Row 194 N1 (sage-1634): a delete writes on the revision its request read when it was raised,
+    // so a write since then makes it stale. The revision is checked here, before the revoke, because
+    // the writer's own check comes after it. A write between this read and the writer's lock still
+    // revokes and then refuses (BUILD.md follow-up).
+    if (writer.read(business).revision !== revision) throw new OrganizationError("revision-conflict", "organization revision changed; read again");
     if (beforeWrite) beforeWrite();
     const receipt = writer.write(business, next, { revision, actor, context });
     return { ...read(business), transaction: receipt.transaction, restart: false };