diff --git a/lib/gstack-memory-helpers.ts b/lib/gstack-memory-helpers.ts
index 8b20f32031..472410e345 100644
--- a/lib/gstack-memory-helpers.ts
+++ b/lib/gstack-memory-helpers.ts
@@ -19,7 +19,7 @@
 
 import { existsSync, readFileSync, writeFileSync, mkdirSync, statSync, appendFileSync } from "fs";
 import { dirname, join } from "path";
-import { execSync, execFileSync } from "child_process";
+import { execSync, execFileSync, spawnSync } from "child_process";
 import { homedir } from "os";
 
 // ── Types ──────────────────────────────────────────────────────────────────
@@ -247,9 +247,16 @@ export function detectEngineTier(): EngineDetect {
 function freshDetectEngineTier(): EngineDetect {
   const now = Date.now();
   try {
-    const out = execSync("gbrain doctor --json --fast 2>/dev/null", { encoding: "utf-8", timeout: 5000 });
-    const parsed = JSON.parse(out);
-    const engine: EngineTier = parsed?.engine === "supabase" ? "supabase" : parsed?.engine === "pglite" ? "pglite" : "unknown";
+    const result = spawnSync("gbrain", ["doctor", "--json", "--fast"], {
+      encoding: "utf-8", timeout: 5000, stdio: ["ignore", "pipe", "ignore"], env: process.env,
+    });
+    if (result.error) return { engine: "unknown", detected_at: now, schema_version: 1 };
+
+    const parsed = JSON.parse(result.stdout);
+    const engine = detectEngineFromDoctorJson(parsed);
+    if (engine === "unknown" && process.env.GSTACK_DEBUG) {
+      process.stderr.write(`[gstack-memory-helpers] unable to detect gbrain engine from doctor JSON: ${JSON.stringify(parsed)}\n`);
+    }
     return {
       engine,
       supabase_url: parsed?.supabase_url || undefined,
@@ -261,6 +268,23 @@ function freshDetectEngineTier(): EngineDetect {
   }
 }
 
+function detectEngineFromDoctorJson(parsed: unknown): EngineTier {
+  const obj = (parsed && typeof parsed === "object" ? parsed : {}) as Record<string, unknown>;
+  const direct = [obj.engine, obj.engine_kind, obj.backend, obj.engine_type].find(isEngineTier);
+  if (direct) return direct;
+  const check = Array.isArray(obj.checks)
+    ? obj.checks.find((c) => c && typeof c === "object" && /engine|backend|kind/i.test(String((c as Record<string, unknown>).name)))
+    : null;
+  const nested = check
+    ? [check.value, check.engine, check.kind].find(isEngineTier)
+    : null;
+  return nested || "unknown";
+}
+
+function isEngineTier(value: unknown): value is EngineTier {
+  return value === "supabase" || value === "pglite";
+}
+
 // ── Public: parseSkillManifest ────────────────────────────────────────────
 
 /**
diff --git a/test/gstack-memory-helpers.test.ts b/test/gstack-memory-helpers.test.ts
index 864fde635c..41ca18f703 100644
--- a/test/gstack-memory-helpers.test.ts
+++ b/test/gstack-memory-helpers.test.ts
@@ -11,7 +11,7 @@
  * Free-tier (~50ms total). Runs in `bun test`.
  */
 
-import { describe, it, expect, beforeEach, afterAll } from "bun:test";
+import { describe, it, expect, beforeEach, afterEach, afterAll } from "bun:test";
 import { mkdtempSync, writeFileSync, readFileSync, existsSync, rmSync, mkdirSync } from "fs";
 import { tmpdir } from "os";
 import { join } from "path";
@@ -272,19 +272,34 @@ describe("withErrorContext", () => {
 
 describe("detectEngineTier", () => {
   let savedHome: string | undefined;
+  let savedPath: string | undefined;
   let testHome: string;
 
   beforeEach(() => {
     savedHome = process.env.GSTACK_HOME;
+    savedPath = process.env.PATH;
     testHome = mkdtempSync(join(tmpdir(), "gstack-test-engine-"));
     process.env.GSTACK_HOME = testHome;
+    process.env.PATH = `${testHome}:${savedPath || ""}`;
+    writeFileSync(join(testHome, "gbrain"), "#!/bin/sh\nprintf '%s\\n' \"$GSTACK_TEST_GBRAIN_STDOUT\"\nexit \"$GSTACK_TEST_GBRAIN_STATUS\"\n", { mode: 0o755 });
+    mockDoctor('{"engine":"pglite","status":"ok"}');
   });
 
-  afterAll(() => {
+  afterEach(() => {
+    if (savedPath === undefined) delete process.env.PATH;
+    else process.env.PATH = savedPath;
     if (savedHome === undefined) delete process.env.GSTACK_HOME;
     else process.env.GSTACK_HOME = savedHome;
+    delete process.env.GSTACK_TEST_GBRAIN_STDOUT;
+    delete process.env.GSTACK_TEST_GBRAIN_STATUS;
+    rmSync(testHome, { recursive: true, force: true });
   });
 
+  function mockDoctor(stdout: string, exitCode = 0) {
+    process.env.GSTACK_TEST_GBRAIN_STDOUT = stdout;
+    process.env.GSTACK_TEST_GBRAIN_STATUS = String(exitCode);
+  }
+
   it("returns a valid EngineDetect shape (engine, detected_at, schema_version)", () => {
     const result = detectEngineTier();
     expect(["pglite", "supabase", "unknown"]).toContain(result.engine);
@@ -293,6 +308,20 @@ describe("detectEngineTier", () => {
     expect(result.detected_at).toBeGreaterThan(0);
   });
 
+  for (const [name, stdout, exitCode, supabaseUrl] of [
+    ["preserves schema_version 1 engine detection from doctor output", '{"engine":"supabase","supabase_url":"https://example.supabase.co","status":"ok"}', 0, "https://example.supabase.co"],
+    ["detects schema_version 2 engine from top-level doctor fields", '{"status":"ok","schema_version":2,"health_score":100,"engine_kind":"supabase","checks":[]}', 0, undefined],
+    ["detects schema_version 2 engine from checks even when doctor exits non-zero", '{"status":"warn","schema_version":2,"health_score":80,"checks":[{"name":"resolver_health","status":"warn"},{"name":"backend","value":"supabase"}]}', 1, undefined],
+  ] as const) {
+    it(name, () => {
+      mockDoctor(stdout, exitCode);
+      const result = detectEngineTier();
+      expect(result.engine).toBe("supabase");
+      if (supabaseUrl) expect(result.supabase_url).toBe(supabaseUrl);
+      expect(result.schema_version).toBe(1);
+    });
+  }
+
   it("writes a cache file at ~/.gstack/.gbrain-engine-cache.json", () => {
     detectEngineTier();
     const cachePath = join(testHome, ".gbrain-engine-cache.json");