fix(gbrain): classify probe timeout as its own status; sync proceeds instead of skipping (#1964)

The 5s engine probe misclassified healthy-but-slow engines (cold Supabase
pooler connections measured at 6.9-10.7s) as broken-config, so /sync-gbrain
silently skipped code+memory and told the user their config was malformed.

- New "timeout" status: probe killed at the deadline with no recognized
  stderr pattern. Default deadline is now 15s, overridable via
  GSTACK_GBRAIN_PROBE_TIMEOUT_MS (tests set 300ms against a fake that
  sleeps 2s).
- Sync stages PROCEED on timeout with a stderr warning naming the env knob;
  a genuinely-dead engine surfaces its real error at the first operation
  instead of a false config diagnosis.
- Consistency everywhere "ok" gated behavior: gstack-gbrain-detect --is-ok
  exits 0 on timeout, and gen-skill-docs' detection gate accepts it, so a
  slow engine no longer silently suppresses brain-aware features.
- Status cache: key now includes the effective probe timeout (raising it
  invalidates a cached timeout) and GBRAIN_HOME; config detection honors
  GBRAIN_HOME so relocated-home users stop being misclassified as
  missing-config.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

test/gbrain-local-status.test.ts

@@ -6,15 +6,17 @@
  * on PATH that emits canned exit codes + stderr matching the patterns the
  * classifier looks for.
  *
- * Five status cases:
+ * Six status cases:
  *   1. no-cli         — gbrain absent from PATH
- *   2. missing-config — gbrain present, ~/.gbrain/config.json absent
+ *   2. missing-config — gbrain present, config.json absent (honors GBRAIN_HOME)
  *   3. broken-config  — gbrain present, config exists, stderr contains "config.json"
  *   4. broken-db      — gbrain present, config exists, stderr contains "Cannot connect to database"
- *   5. ok             — gbrain present, config exists, sources list returns valid JSON
+ *   5. timeout        — probe exceeds GSTACK_GBRAIN_PROBE_TIMEOUT_MS with no recognized error (#1964)
+ *   6. ok             — gbrain present, config exists, sources list returns valid JSON
  *
- * Plus cache behavior: hit, TTL expiry, invariant invalidation (HOME change),
- * --no-cache bypass.
+ * Plus cache behavior: hit, TTL expiry, invariant invalidation (HOME change,
+ * probe-timeout change), --no-cache bypass. Timeout tests keep runtime sane by
+ * setting GSTACK_GBRAIN_PROBE_TIMEOUT_MS=300 against a fake gbrain that sleeps 2s.
  */
 
 import { describe, it, expect, beforeEach, afterEach } from "bun:test";
@@ -31,10 +33,14 @@ import {
 import { tmpdir } from "os";
 import { join } from "path";
 
+import { spawnSync } from "child_process";
+
 import {
   localEngineStatus,
   cacheFilePath,
+  probeTimeoutMs,
   CACHE_TTL_MS,
+  DEFAULT_PROBE_TIMEOUT_MS,
   type LocalEngineStatus,
 } from "../lib/gbrain-local-status";
 
@@ -55,7 +61,7 @@ interface FakeEnv {
  */
 function makeEnv(opts: {
   withGbrain?: boolean;
-  gbrainBehavior?: "ok" | "broken-db" | "broken-config" | "throws";
+  gbrainBehavior?: "ok" | "broken-db" | "broken-config" | "throws" | "slow";
   withConfig?: boolean;
 }): FakeEnv {
   const tmp = mkdtempSync(join(tmpdir(), "gbrain-local-status-test-"));
@@ -96,8 +102,24 @@ function makeEnv(opts: {
 }
 
 function makeFakeGbrainScript(
-  behavior: "ok" | "broken-db" | "broken-config" | "throws",
+  behavior: "ok" | "broken-db" | "broken-config" | "throws" | "slow",
 ): string {
+  // "slow": healthy engine on a cold pooler connection (#1964) — sleeps past
+  // the (test-lowered) probe timeout, then would answer fine.
+  if (behavior === "slow") {
+    return `#!/bin/sh
+if [ "$1" = "--version" ]; then
+  echo "gbrain 0.33.1.0"
+  exit 0
+fi
+if [ "$1 $2" = "sources list" ]; then
+  sleep 2
+  echo '{"sources":[]}'
+  exit 0
+fi
+exit 0
+`;
+  }
   const stderrLine =
     behavior === "broken-db"
       ? 'echo "Cannot connect to database: . Fix: Check your connection URL in ~/.gbrain/config.json" >&2'
@@ -136,17 +158,19 @@ function applyEnv(env: FakeEnv): () => void {
     HOME: process.env.HOME,
     PATH: process.env.PATH,
     GSTACK_HOME: process.env.GSTACK_HOME,
+    GBRAIN_HOME: process.env.GBRAIN_HOME,
+    GSTACK_GBRAIN_PROBE_TIMEOUT_MS: process.env.GSTACK_GBRAIN_PROBE_TIMEOUT_MS,
   };
   process.env.HOME = env.home;
   process.env.PATH = `${env.bindir}:/usr/bin:/bin`;
   process.env.GSTACK_HOME = env.gstackHome;
+  delete process.env.GBRAIN_HOME;
+  delete process.env.GSTACK_GBRAIN_PROBE_TIMEOUT_MS;
   return () => {
-    if (prev.HOME === undefined) delete process.env.HOME;
-    else process.env.HOME = prev.HOME;
-    if (prev.PATH === undefined) delete process.env.PATH;
-    else process.env.PATH = prev.PATH;
-    if (prev.GSTACK_HOME === undefined) delete process.env.GSTACK_HOME;
-    else process.env.GSTACK_HOME = prev.GSTACK_HOME;
+    for (const [k, v] of Object.entries(prev)) {
+      if (v === undefined) delete process.env[k];
+      else process.env[k] = v;
+    }
   };
 }
 
@@ -206,6 +230,73 @@ describe("lib/gbrain-local-status — five status cases", () => {
     restoreEnv = applyEnv(env);
     expect(localEngineStatus({ noCache: true })).toBe("ok");
   });
+
+  it("returns 'timeout' (not broken-config) when the probe exceeds the deadline (#1964)", () => {
+    env = makeEnv({ withGbrain: true, gbrainBehavior: "slow", withConfig: true });
+    restoreEnv = applyEnv(env);
+    process.env.GSTACK_GBRAIN_PROBE_TIMEOUT_MS = "300";
+    expect(localEngineStatus({ noCache: true })).toBe("timeout");
+  });
+
+  it("honors GBRAIN_HOME for config detection (codex D11)", () => {
+    // Config lives ONLY at the alternate GBRAIN_HOME; ~/.gbrain has none.
+    env = makeEnv({ withGbrain: true, gbrainBehavior: "ok", withConfig: false });
+    restoreEnv = applyEnv(env);
+    const altHome = join(env.tmp, "alt-gbrain");
+    mkdirSync(altHome, { recursive: true });
+    writeFileSync(
+      join(altHome, "config.json"),
+      JSON.stringify({ engine: "pglite", database_url: "pglite:///fake" }),
+    );
+    // Without GBRAIN_HOME: misclassified as missing-config.
+    expect(localEngineStatus({ noCache: true })).toBe("missing-config");
+    // With GBRAIN_HOME: the relocated config is found.
+    process.env.GBRAIN_HOME = altHome;
+    expect(localEngineStatus({ noCache: true })).toBe("ok");
+  });
+});
+
+describe("gstack-gbrain-detect --is-ok — timeout is usable (eng review D1)", () => {
+  it("exits 0 when the engine probe times out (slow-but-healthy must not suppress brain features)", () => {
+    const env = makeEnv({ withGbrain: true, gbrainBehavior: "slow", withConfig: true });
+    try {
+      const detect = join(import.meta.dir, "..", "bin", "gstack-gbrain-detect");
+      const r = spawnSync(process.execPath, [detect, "--is-ok"], {
+        encoding: "utf-8",
+        timeout: 20_000,
+        env: {
+          ...process.env,
+          HOME: env.home,
+          GSTACK_HOME: env.gstackHome,
+          PATH: `${env.bindir}:/usr/bin:/bin`,
+          GSTACK_GBRAIN_PROBE_TIMEOUT_MS: "300",
+          GSTACK_DETECT_NO_CACHE: "1",
+          GBRAIN_HOME: "",
+        },
+      });
+      expect(r.status).toBe(0);
+    } finally {
+      env.cleanup();
+    }
+  });
+});
+
+describe("probeTimeoutMs — env override parsing", () => {
+  it("defaults to 15s when unset", () => {
+    expect(probeTimeoutMs({})).toBe(DEFAULT_PROBE_TIMEOUT_MS);
+    expect(DEFAULT_PROBE_TIMEOUT_MS).toBe(15_000);
+  });
+
+  it("parses a numeric override", () => {
+    expect(probeTimeoutMs({ GSTACK_GBRAIN_PROBE_TIMEOUT_MS: "300" })).toBe(300);
+  });
+
+  it("falls back to the default on non-numeric, empty, and non-positive values", () => {
+    expect(probeTimeoutMs({ GSTACK_GBRAIN_PROBE_TIMEOUT_MS: "fast" })).toBe(DEFAULT_PROBE_TIMEOUT_MS);
+    expect(probeTimeoutMs({ GSTACK_GBRAIN_PROBE_TIMEOUT_MS: "" })).toBe(DEFAULT_PROBE_TIMEOUT_MS);
+    expect(probeTimeoutMs({ GSTACK_GBRAIN_PROBE_TIMEOUT_MS: "0" })).toBe(DEFAULT_PROBE_TIMEOUT_MS);
+    expect(probeTimeoutMs({ GSTACK_GBRAIN_PROBE_TIMEOUT_MS: "-5" })).toBe(DEFAULT_PROBE_TIMEOUT_MS);
+  });
 });
 
 describe("lib/gbrain-local-status — cache behavior", () => {
@@ -275,6 +366,31 @@ describe("lib/gbrain-local-status — cache behavior", () => {
     expect(localEngineStatus({ noCache: false })).toBe("broken-db");
   });
 
+  it("caches a 'timeout' result (sync probes 3x/run — uncached would cost 3 deadlines)", () => {
+    env = makeEnv({ withGbrain: true, gbrainBehavior: "slow", withConfig: true });
+    restoreEnv = applyEnv(env);
+    process.env.GSTACK_GBRAIN_PROBE_TIMEOUT_MS = "300";
+    expect(localEngineStatus({ noCache: false })).toBe("timeout");
+
+    // Swap the fake to a fast-ok binary; the cached timeout should still win
+    // within TTL (same key — proving the result was cached, not re-probed).
+    writeFileSync(join(env.bindir, "gbrain"), makeFakeGbrainScript("ok"));
+    chmodSync(join(env.bindir, "gbrain"), 0o755);
+    expect(localEngineStatus({ noCache: false })).toBe("timeout");
+  });
+
+  it("invalidates a cached 'timeout' when GSTACK_GBRAIN_PROBE_TIMEOUT_MS changes (key invariant, codex D13)", () => {
+    env = makeEnv({ withGbrain: true, gbrainBehavior: "slow", withConfig: true });
+    restoreEnv = applyEnv(env);
+    process.env.GSTACK_GBRAIN_PROBE_TIMEOUT_MS = "300";
+    expect(localEngineStatus({ noCache: false })).toBe("timeout");
+
+    // User raises the timeout past the fake's 2s sleep: cache key changes,
+    // re-probe succeeds.
+    process.env.GSTACK_GBRAIN_PROBE_TIMEOUT_MS = "5000";
+    expect(localEngineStatus({ noCache: false })).toBe("ok");
+  });
+
   it("invalidates cache when HOME changes (key invariant)", () => {
     env = makeEnv({ withGbrain: true, gbrainBehavior: "ok", withConfig: true });
     restoreEnv = applyEnv(env);