diff --git a/__tests__/audit/replay-source-equivalence.test.ts b/__tests__/audit/replay-source-equivalence.test.ts
index c77af845..64e10080 100644
--- a/__tests__/audit/replay-source-equivalence.test.ts
+++ b/__tests__/audit/replay-source-equivalence.test.ts
@@ -194,7 +194,7 @@ describe("the audit replays the same policies from either source", () => {
     const raw = execFileSync("bun", [probe], { cwd: REPO, encoding: "utf8" }).trim().split("\n").pop() ?? "";
     const measured = JSON.parse(raw) as { compiled: string; mixed: string; policies: number };
 
-    expect(measured.policies).toBe(38);
+    expect(measured.policies).toBe(39);
     // The pack's function text IS the compiled function text, so the cache key
     // does not move and no existing audit result is invalidated.
     expect(measured.mixed).toBe(measured.compiled);
diff --git a/__tests__/hooks/builtin-pack-conformance.test.ts b/__tests__/hooks/builtin-pack-conformance.test.ts
index 36f6a228..7e0b9e19 100644
--- a/__tests__/hooks/builtin-pack-conformance.test.ts
+++ b/__tests__/hooks/builtin-pack-conformance.test.ts
@@ -108,7 +108,7 @@ describe("builtin pack conformance", () => {
   it("packages every builtin except the one packs may not carry", () => {
     const expected = POLICY_CATALOG.filter((p) => !p.alwaysOn).map((p) => p.name);
     expect(manifest.policies.map((p) => p.name)).toEqual(expected);
-    expect(manifest.policies).toHaveLength(38);
+    expect(manifest.policies).toHaveLength(39);
     // The omitted one is the guard against disabling failproofai. pack-manifest
     // REFUSES a pack declaring alwaysOn, so shipping it here would produce a
     // pack our own loader rejects.
diff --git a/__tests__/hooks/builtin-policies.test.ts b/__tests__/hooks/builtin-policies.test.ts
index cd3c4500..0e6034a4 100644
--- a/__tests__/hooks/builtin-policies.test.ts
+++ b/__tests__/hooks/builtin-policies.test.ts
@@ -38,8 +38,8 @@ describe("hooks/builtin-policies", () => {
 
   describe("BUILTIN_POLICIES", () => {
     // 40 before `block-self-pause` was merged into `block-failproofai-commands`.
-    it("has 39 built-in policies", () => {
-      expect(BUILTIN_POLICIES).toHaveLength(39);
+    it("has 40 built-in policies", () => {
+      expect(BUILTIN_POLICIES).toHaveLength(40);
     });
 
     it("has 11 default-enabled policies", () => {
@@ -2587,10 +2587,11 @@ describe("hooks/builtin-policies", () => {
   describe("workflow policy metadata", () => {
     const workflowPolicies = BUILTIN_POLICIES.filter((p) => p.category === "Workflow");
 
-    it("all 5 workflow policies exist", () => {
-      expect(workflowPolicies).toHaveLength(5);
+    it("all 6 workflow policies exist", () => {
+      expect(workflowPolicies).toHaveLength(6);
       const names = workflowPolicies.map((p) => p.name).sort();
       expect(names).toEqual([
+        "require-battery-green-before-stop",
         "require-ci-green-before-stop",
         "require-commit-before-stop",
         "require-no-conflicts-before-stop",
diff --git a/__tests__/hooks/policy-catalog.test.ts b/__tests__/hooks/policy-catalog.test.ts
index 9d4529b0..a0a7c96d 100644
--- a/__tests__/hooks/policy-catalog.test.ts
+++ b/__tests__/hooks/policy-catalog.test.ts
@@ -38,13 +38,14 @@ const EXPECTED_ORDER = [
   "warn-background-process", "warn-repeated-tool-calls", "require-commit-before-stop",
   "require-push-before-stop", "require-pr-before-stop",
   "require-no-conflicts-before-stop", "require-ci-green-before-stop",
+  "require-battery-green-before-stop",
 ];
 
 describe("policy catalog / implementation split", () => {
   describe("the join", () => {
     it("keeps catalog and joined view the same length and order", () => {
-      expect(POLICY_CATALOG).toHaveLength(39);
-      expect(BUILTIN_POLICIES).toHaveLength(39);
+      expect(POLICY_CATALOG).toHaveLength(40);
+      expect(BUILTIN_POLICIES).toHaveLength(40);
       expect(BUILTIN_POLICIES.map((p) => p.name)).toEqual(POLICY_CATALOG.map((e) => e.name));
     });
 
@@ -59,20 +60,20 @@ describe("policy catalog / implementation split", () => {
       expect(holes).toEqual([]);
     });
 
-    it("assigns 39 DISTINCT implementations, never a shared wrapper", () => {
-      // The wrapper-collapse guard. `fn: (ctx) => IMPLS[name](ctx)` yields 39
+    it("assigns 40 DISTINCT implementations, never a shared wrapper", () => {
+      // The wrapper-collapse guard. `fn: (ctx) => IMPLS[name](ctx)` yields 40
       // distinct function OBJECTS with near-identical source text, which freezes
       // audit/cache.ts's engineVersion — it then stops changing when policy logic
       // changes and stale audit results are served for the full 30-day TTL with
       // no symptom anywhere.
-      expect(new Set(BUILTIN_POLICIES.map((p) => p.fn.toString())).size).toBe(39);
+      expect(new Set(BUILTIN_POLICIES.map((p) => p.fn.toString())).size).toBe(40);
     });
 
     it("has unique names", () => {
       // findBuiltin takes the FIRST match and registerPolicy takes the LAST — a
       // duplicate silently registers one policy fewer while the audit title comes
       // from the other copy.
-      expect(new Set(BUILTIN_POLICIES.map((p) => p.name)).size).toBe(39);
+      expect(new Set(BUILTIN_POLICIES.map((p) => p.name)).size).toBe(40);
     });
 
     it("adds no fields the catalog did not have", () => {
diff --git a/__tests__/hooks/require-battery-green-before-stop.test.ts b/__tests__/hooks/require-battery-green-before-stop.test.ts
new file mode 100644
index 00000000..1e9483ee
--- /dev/null
+++ b/__tests__/hooks/require-battery-green-before-stop.test.ts
@@ -0,0 +1,83 @@
+// @vitest-environment node
+import { describe, it, expect } from "vitest";
+import { mkdtempSync, mkdirSync, writeFileSync, chmodSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import type { PolicyContext } from "../../src/hooks/policy-types";
+
+// Import the builtin policies array to get the policy function
+import { BUILTIN_POLICIES } from "../../src/hooks/builtin-policies";
+
+const policy = BUILTIN_POLICIES.find((p) => p.name === "require-battery-green-before-stop")!;
+
+function makeCtx(overrides: Partial<PolicyContext>): PolicyContext {
+  return {
+    eventType: "Stop",
+    payload: {},
+    ...overrides,
+  } as PolicyContext;
+}
+
+function repoWithBattery(exitCode: 0 | 1): string {
+  const dir = mkdtempSync(join(tmpdir(), "fpai-battery-"));
+  const scriptDir = join(dir, "scripts", "verify");
+  mkdirSync(scriptDir, { recursive: true });
+  const script = join(scriptDir, "battery.sh");
+  writeFileSync(script, `#!/bin/sh\nexit ${exitCode}\n`);
+  chmodSync(script, 0o755);
+  return dir;
+}
+
+describe("require-battery-green-before-stop policy", () => {
+  it("exists in BUILTIN_POLICIES, off by default, Stop-only", () => {
+    expect(policy).toBeDefined();
+    expect(policy.defaultEnabled).toBe(false);
+    expect(policy.match.events).toEqual(["Stop"]);
+  });
+
+  it("allows when no cwd in session (graceful fallback)", async () => {
+    const result = await policy.fn(makeCtx({}));
+    expect(result.decision).toBe("allow");
+  });
+
+  it("allows when no battery script exists (fail-open)", async () => {
+    const dir = mkdtempSync(join(tmpdir(), "fpai-nobattery-"));
+    const result = await policy.fn(makeCtx({ session: { cwd: dir } }));
+    expect(result.decision).toBe("allow");
+    expect(result.reason).toMatch(/no .*battery/i);
+  });
+
+  it("allows when the battery passes", async () => {
+    const dir = repoWithBattery(0);
+    const result = await policy.fn(makeCtx({ session: { cwd: dir } }));
+    expect(result.decision).toBe("allow");
+  });
+
+  it("denies when the battery fails", async () => {
+    const dir = repoWithBattery(0);
+    const sub = join(dir, "packages", "app");
+    mkdirSync(sub, { recursive: true });
+    writeFileSync(join(dir, "scripts", "verify", "battery.sh"), "#!/bin/sh\nexit 1\n");
+    chmodSync(join(dir, "scripts", "verify", "battery.sh"), 0o755);
+    const result = await policy.fn(makeCtx({ session: { cwd: sub } }));
+    expect(result.decision).toBe("deny");
+    expect(result.reason).toMatch(/battery/i);
+  });
+
+  it("finds the battery from a nested working directory", async () => {
+    const dir = repoWithBattery(0);
+    const sub = join(dir, "a", "b");
+    mkdirSync(sub, { recursive: true });
+    const result = await policy.fn(makeCtx({ session: { cwd: sub } }));
+    expect(result.decision).toBe("allow");
+  });
+
+  it("allows in plan mode without running anything", async () => {
+    // A red battery repo: allow here proves the plan-mode bypass,
+    // since the same repo denies without plan mode (see above).
+    const result = await policy.fn(
+      makeCtx({ session: { cwd: repoWithBattery(1), permissionMode: "plan" } }),
+    );
+    expect(result.decision).toBe("allow");
+  });
+});
diff --git a/src/hooks/builtin-policies.ts b/src/hooks/builtin-policies.ts
index 8ca25220..a55e5476 100644
--- a/src/hooks/builtin-policies.ts
+++ b/src/hooks/builtin-policies.ts
@@ -3070,6 +3070,38 @@ function requireCiGreenBeforeStop(ctx: PolicyContext): PolicyResult {
   }
 }
 
+function findBatteryUp(startDir: string, maxDepth = 5): string | null {
+  let dir = resolve(startDir);
+  for (let i = 0; i <= maxDepth; i++) {
+    const candidate = join(dir, "scripts", "verify", "battery.sh");
+    try {
+      if (statSync(candidate).isFile()) return candidate;
+    } catch {
+      // not here — keep climbing
+    }
+    const parent = resolve(join(dir, ".."));
+    if (parent === dir) return null;
+    dir = parent;
+  }
+  return null;
+}
+
+function requireBatteryGreenBeforeStop(ctx: PolicyContext): PolicyResult {
+  if (isPlanMode(ctx)) return allow("Plan mode — no changes made, skipping battery check.");
+  const cwd = ctx.session?.cwd;
+  if (!cwd) return allow("No working directory available, skipping battery check.");
+  const battery = findBatteryUp(cwd);
+  if (!battery) return allow("No scripts/verify/battery.sh found, skipping battery check.");
+  try {
+    execFileSync("sh", [battery, "--l0"], {
+      cwd, encoding: "utf8", stdio: ["pipe", "pipe", "pipe"], timeout: 120000,
+    });
+  } catch {
+    return deny("Battery L0 red. Run sh scripts/verify/battery.sh --full, fix, then stop.");
+  }
+  return allow("Battery L0 green.");
+}
+
 // -- Registry --
 
 /**
@@ -3123,6 +3155,7 @@ const POLICY_IMPLEMENTATIONS: Record<string, PolicyFunction> = {
   "require-pr-before-stop": requirePrBeforeStop,
   "require-no-conflicts-before-stop": requireNoConflictsBeforeStop,
   "require-ci-green-before-stop": requireCiGreenBeforeStop,
+  "require-battery-green-before-stop": requireBatteryGreenBeforeStop,
 };
 
 /**
diff --git a/src/hooks/policy-catalog.ts b/src/hooks/policy-catalog.ts
index 7659772b..54b4e2ac 100644
--- a/src/hooks/policy-catalog.ts
+++ b/src/hooks/policy-catalog.ts
@@ -540,4 +540,13 @@ export const POLICY_CATALOG: PolicyCatalogEntry[] = [
     defaultEnabled: false,
     category: "Workflow",
   },
+  {
+    name: "require-battery-green-before-stop",
+    displayTitle: "Stopped with red local battery",
+    impact: "Unverified work can't ship.",
+    description: "Require battery.sh L0 green before stopping; skip when absent",
+    match: { events: ["Stop"] },
+    defaultEnabled: false,
+    category: "Workflow",
+  },
 ];