diff --git a/CHANGELOG.md b/CHANGELOG.md
index 09d3cac92..5f1a13758 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,15 @@
 # Changelog
 
+## [1.93.13.0] - 2026-11-02
+
+**gstack's own tests no longer write into a developer's real gbrain.** If you export `GBRAIN_DATABASE_URL` for your working brain and run gstack's test suite, tests that spawn bins with a temp `HOME` used to pass that URL straight through. With no gbrain config under the temp `HOME`, the real `gbrain` on your PATH then added `brain-sync-remote-*` sources and test pages to your live brain. From #3466 by @AndreIntelas.
+
+### Fixed
+- **The test preload (`test-setup.ts`) strips the variables gbrain uses to pick a brain** before any test module loads: `GBRAIN_DATABASE_URL`, `GBRAIN_DIRECT_DATABASE_URL`, `DATABASE_URL` and `GBRAIN_HOME`. It prints one line on stderr for each variable it strips. This covers `bun test <file>` and every shard of `bun run test`.
+
+### Tests
+- `test/state-root-config-merge.test.ts`: a `bun test` run with all four variables exported spawns a child under a temp `HOME` that calls `buildGbrainEnv`, and the child sees none of them. It fails on main.
+
 ## [1.93.12.0] - 2026-11-02
 
 **The Opus 5.5 `lite` skills now keep the install's gbrain blocks, disabled skills and the Claims Need Evidence rule (GST-944).** The lite tree Capy publishes was rendered without the install's settings. On a machine with gbrain detected, Opus 5.5 sessions lost the brain context-load and save-results blocks that the full install serves, and skills turned off with `disabled_skills` showed up again in the lite router. `./setup --loadout lite` was not affected.
diff --git a/VERSION b/VERSION
index 7f209dd81..c2fc44987 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-1.93.12.0
+1.93.13.0
diff --git a/agents-digest/gstack-AGENTS.md b/agents-digest/gstack-AGENTS.md
index 513f2a765..923c3f576 100644
--- a/agents-digest/gstack-AGENTS.md
+++ b/agents-digest/gstack-AGENTS.md
@@ -1,4 +1,4 @@
-# gstack digest v1.93.12.0 — regenerate/re-copy after upgrading gstack
+# gstack digest v1.93.13.0 — regenerate/re-copy after upgrading gstack
 
 Behavioral rules from gstack (https://github.com/garrytan/gstack), compressed
 for agent hosts without a full skill install. The full skills add workflows,
diff --git a/package.json b/package.json
index 098af7b3f..4c4f97952 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "gstack",
-  "version": "1.93.12",
+  "version": "1.93.13",
   "description": "Garry's Stack — Claude Code skills + fast headless browser. One repo, one install, entire AI engineering workflow.",
   "license": "MIT",
   "type": "module",
diff --git a/test-setup.ts b/test-setup.ts
index 31234cc63..a9c6fc020 100644
--- a/test-setup.ts
+++ b/test-setup.ts
@@ -39,6 +39,15 @@ for (const name of ['GSTACK_STATE_ROOT', 'GSTACK_STATE_DIR']) {
 // an unattended Capy session it never set up. The shard engine strips the same
 // list for the lanes; this reaches direct runs too.
 for (const name of CAPY_LAUNCH_MARKERS) delete process.env[name];
+// The variables gbrain reads to pick a brain (#3466). Tests spawn bins with
+// { ...process.env, HOME: <tmp> }; with no gbrain config under the temp HOME,
+// buildGbrainEnv passes an exported URL through and a real gbrain on PATH
+// writes test pages and sources into the developer's live brain.
+for (const name of ['GBRAIN_DATABASE_URL', 'GBRAIN_DIRECT_DATABASE_URL', 'DATABASE_URL', 'GBRAIN_HOME']) {
+  if (process.env[name] === undefined) continue;
+  delete process.env[name];
+  process.stderr.write(`test-setup: stripped inherited ${name}; tests must not reach a live gbrain\n`);
+}
 process.env.GSTACK_TEST_LEGACY_ROOT = path.join(os.tmpdir(), `gstack-test-legacy-root-${process.pid}-${Date.now()}-unused`);
 // Workflow leases (bin/gstack-lease) default to the installation's git dir;
 // for the dev checkout under test that is this repo's .git, and a live test
diff --git a/test/state-root-config-merge.test.ts b/test/state-root-config-merge.test.ts
index a0e5cd73e..d6a1a25e5 100644
--- a/test/state-root-config-merge.test.ts
+++ b/test/state-root-config-merge.test.ts
@@ -163,4 +163,42 @@ describe('test preload hermeticity', () => {
     expect(r.stderr).toContain('test-setup: stripped inherited GSTACK_STATE_DIR; tests isolate state via GSTACK_HOME');
     expect(r.stderr.match(/test-setup: stripped/g)?.length).toBe(2);
   });
+
+  test('bun test strips an inherited live-brain URL, so a temp-HOME gbrain child never sees it (#3466)', () => {
+    const live = path.join(tmp, 'live-gbrain');
+    fs.mkdirSync(live, { recursive: true });
+    fs.writeFileSync(path.join(live, 'config.json'), JSON.stringify({ database_url: 'postgresql://live-config.invalid/brain' }));
+    const childHome = path.join(tmp, 'child-home');
+    fs.mkdirSync(childHome, { recursive: true });
+    const probe = path.join(tmp, 'brain-probe.test.ts');
+    fs.writeFileSync(probe, [
+      "import { test, expect } from 'bun:test';",
+      "import { spawnSync } from 'child_process';",
+      "test('probe', () => {",
+      "  const script = \"const { buildGbrainEnv } = require(\" + JSON.stringify(" + JSON.stringify(path.join(ROOT, 'lib', 'gbrain-exec.ts')) + ") + \"); const e = buildGbrainEnv(); console.log(['GBRAIN_DATABASE_URL','GBRAIN_DIRECT_DATABASE_URL','DATABASE_URL','GBRAIN_HOME'].map(k => k + '=' + (e[k] ?? '<unset>')).join(' '));\";",
+      "  const r = spawnSync(process.execPath, ['--no-env-file', '--config=/dev/null', '-e', script], {",
+      "    env: { ...process.env, HOME: " + JSON.stringify(childHome) + " }, encoding: 'utf-8', timeout: 30_000,",
+      "  });",
+      "  expect(r.stdout.trim()).toBe('GBRAIN_DATABASE_URL=<unset> GBRAIN_DIRECT_DATABASE_URL=<unset> DATABASE_URL=<unset> GBRAIN_HOME=<unset>');",
+      "});",
+    ].join('\n'));
+    const r = spawnSync('bun', ['test', '--preload', path.join(ROOT, 'test-setup.ts'), probe], {
+      cwd: tmp,
+      env: {
+        ...env, GSTACK_HOME: resolved,
+        GBRAIN_DATABASE_URL: 'postgresql://live-brain.invalid/brain',
+        GBRAIN_DIRECT_DATABASE_URL: 'postgresql://live-brain.invalid/direct',
+        DATABASE_URL: 'postgresql://live-brain.invalid/fallback',
+        GBRAIN_HOME: live,
+      },
+      encoding: 'utf-8',
+      timeout: 60_000,
+    });
+    expect(r.stderr).not.toContain('live-brain.invalid');
+    expect(r.stderr).not.toContain('live-config.invalid');
+    expect(r.status).toBe(0);
+    for (const name of ['GBRAIN_DATABASE_URL', 'GBRAIN_DIRECT_DATABASE_URL', 'DATABASE_URL', 'GBRAIN_HOME']) {
+      expect(r.stderr).toContain(`test-setup: stripped inherited ${name}; tests must not reach a live gbrain`);
+    }
+  });
 });