diff --git a/server/src/__tests__/heartbeat-run-scratch-recovery.test.ts b/server/src/__tests__/heartbeat-run-scratch-recovery.test.ts
new file mode 100644
index 00000000000..4a0b8aa7339
--- /dev/null
+++ b/server/src/__tests__/heartbeat-run-scratch-recovery.test.ts
@@ -0,0 +1,129 @@
+import { randomUUID } from "node:crypto";
+import fs from "node:fs/promises";
+import os from "node:os";
+import path from "node:path";
+import { afterAll, afterEach, beforeAll, describe, expect, it, vi } from "vitest";
+import { agents, companies, createDb, heartbeatRunEvents, heartbeatRuns } from "@paperclipai/db";
+import { getEmbeddedPostgresTestSupport, startEmbeddedPostgresTestDatabase } from "./helpers/embedded-postgres.js";
+
+vi.mock("../telemetry.ts", () => ({ getTelemetryClient: () => ({ track: vi.fn() }) }));
+vi.mock("../middleware/logger.js", () => ({
+  logger: {
+    child: vi.fn(function child(this: unknown) {
+      return this;
+    }),
+    trace: vi.fn(),
+    debug: vi.fn(),
+    info: vi.fn(),
+    warn: vi.fn(),
+    error: vi.fn(),
+    fatal: vi.fn(),
+  },
+  httpLogger: vi.fn(),
+}));
+
+import { heartbeatService } from "../services/heartbeat.ts";
+import { HEARTBEAT_RUN_SCRATCH_MARKER } from "../services/run-scratch.js";
+
+const embeddedPostgresSupport = await getEmbeddedPostgresTestSupport();
+const describeEmbeddedPostgres = embeddedPostgresSupport.supported ? describe : describe.skip;
+
+describeEmbeddedPostgres("heartbeat recovery sweeps orphaned run scratch", () => {
+  let db!: ReturnType<typeof createDb>;
+  let tempDb: Awaited<ReturnType<typeof startEmbeddedPostgresTestDatabase>> | null = null;
+  let originalTmpdir: string | undefined;
+  let scratchRoot = "";
+
+  beforeAll(async () => {
+    tempDb = await startEmbeddedPostgresTestDatabase("paperclip-run-scratch-recovery-");
+    db = createDb(tempDb.connectionString);
+    originalTmpdir = process.env.TMPDIR;
+    scratchRoot = await fs.mkdtemp(path.join(os.tmpdir(), "paperclip-scratch-root-"));
+    process.env.TMPDIR = scratchRoot;
+  }, 20_000);
+
+  afterEach(async () => {
+    await db.delete(heartbeatRunEvents);
+    await db.delete(heartbeatRuns);
+    await db.delete(agents);
+    await db.delete(companies);
+    await fs.rm(scratchRoot, { recursive: true, force: true });
+    await fs.mkdir(scratchRoot, { recursive: true });
+  });
+
+  afterAll(async () => {
+    if (originalTmpdir === undefined) delete process.env.TMPDIR;
+    else process.env.TMPDIR = originalTmpdir;
+    await fs.rm(scratchRoot, { recursive: true, force: true });
+    await tempDb?.cleanup();
+  });
+
+  async function seedRun(status: string) {
+    const companyId = randomUUID();
+    const agentId = randomUUID();
+    const runId = randomUUID();
+    await db.insert(companies).values({
+      id: companyId,
+      name: "Paperclip",
+      issuePrefix: `T${companyId.replace(/-/g, "").slice(0, 6).toUpperCase()}`,
+      requireBoardApprovalForNewAgents: false,
+    });
+    await db.insert(agents).values({
+      id: agentId,
+      companyId,
+      name: "Coder",
+      role: "engineer",
+      status: "idle",
+      adapterType: "codex_local",
+      adapterConfig: {},
+      runtimeConfig: {},
+      permissions: {},
+    });
+    await db.insert(heartbeatRuns).values({
+      id: runId,
+      companyId,
+      agentId,
+      invocationSource: "on_demand",
+      status,
+      nextEventSeq: 1,
+    });
+    return { companyId, agentId, runId };
+  }
+
+  async function leaveScratch(run: { companyId: string; agentId: string; runId: string }, runIdInMarker = run.runId) {
+    const dir = await fs.mkdtemp(path.join(scratchRoot, `paperclip-run-x-${run.runId.slice(0, 12)}-`));
+    await fs.writeFile(
+      path.join(dir, HEARTBEAT_RUN_SCRATCH_MARKER),
+      JSON.stringify({
+        version: 1,
+        companyId: run.companyId,
+        agentId: run.agentId,
+        runId: runIdInMarker,
+        issueId: null,
+        issueIdentifier: null,
+        createdAt: new Date().toISOString(),
+      }),
+    );
+    return dir;
+  }
+
+  const exists = (p: string) => fs.stat(p).then(() => true, () => false);
+
+  it("removes a terminal run's leftover directory and keeps others, even beside a malformed marker", async () => {
+    const terminal = await seedRun("failed");
+    const queued = await seedRun("queued");
+    const terminalDir = await leaveScratch(terminal);
+    const queuedDir = await leaveScratch(queued);
+    const malformedDir = await leaveScratch(terminal, "not-a-uuid");
+    const unknownRunDir = await leaveScratch(terminal, randomUUID());
+    const unmarkedDir = await fs.mkdtemp(path.join(scratchRoot, "paperclip-run-x-unmarked-"));
+
+    await heartbeatService(db).reapOrphanedRuns();
+
+    expect(await exists(terminalDir)).toBe(false);
+    expect(await exists(queuedDir)).toBe(true);
+    expect(await exists(malformedDir)).toBe(true);
+    expect(await exists(unknownRunDir)).toBe(true);
+    expect(await exists(unmarkedDir)).toBe(true);
+  });
+});
diff --git a/server/src/services/heartbeat.ts b/server/src/services/heartbeat.ts
index 6dff2d1c475..dc73e163043 100644
--- a/server/src/services/heartbeat.ts
+++ b/server/src/services/heartbeat.ts
@@ -471,6 +471,7 @@ import {
   buildHeartbeatRunScratchEnv,
   cleanupHeartbeatRunScratch,
   prepareHeartbeatRunScratch,
+  sweepOrphanedRunScratch,
   type HeartbeatRunScratch,
 } from "./run-scratch.js";
 import {
@@ -3978,6 +3979,16 @@ export function heartbeatService(
                 "failed to record heartbeat run scratch cleanup event",
               );
             });
+            // Earlier process attempts of this run (before a restart) left their
+            // own scratch directories; the run is terminal, so remove them too.
+            if (scratchCleanup.removed) {
+              await sweepOrphanedRunScratch({
+                runId: run.id,
+                resolveRunStates: async (ids) => new Map(ids.map((id) => [id, "terminal" as const])),
+              }).catch((sweepError) => {
+                logger.warn({ err: sweepError, runId: run.id }, "failed to sweep earlier run scratch attempts");
+              });
+            }
           }
         }
         if (latestRun?.status === "interrupted" && latestRun.runtimeMode === "legacy" &&
diff --git a/server/src/services/heartbeat/recovery.ts b/server/src/services/heartbeat/recovery.ts
index 065ecafa922..cd00e460eb0 100644
--- a/server/src/services/heartbeat/recovery.ts
+++ b/server/src/services/heartbeat/recovery.ts
@@ -38,6 +38,8 @@ import { legacyExecutionNeedsReconciliationWithEvidence, terminalizeLegacyExecut
 import { reconcileRetainedWorkspaces } from "../workspace-recovery.js";
 import { randomUUID } from "node:crypto";
 import os from "node:os";
+import { sweepOrphanedRunScratch, type RunScratchSweepRunState } from "../run-scratch.js";
+import { isHeartbeatRunTerminalStatus } from "./run-lifecycle.js";
 import {
   and,
   asc,
@@ -2721,6 +2723,25 @@ export function createHeartbeatRecovery(db: Db, dependencies: HeartbeatRecoveryD
       logger.warn({ err: error }, "failed to retry captured instruction revisions");
     });
 
+    await sweepOrphanedRunScratch({
+      resolveRunStates: async (runIds) => {
+        // Markers are untrusted: only well-formed UUIDs reach the query.
+        const uuid = /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i;
+        const validIds = runIds.filter((id) => uuid.test(id));
+        // A run absent from this database may belong to another instance sharing the temp root.
+        const states = new Map<string, RunScratchSweepRunState>(runIds.map((id) => [id, "unknown"]));
+        if (validIds.length === 0) return states;
+        const rows = await db.select({ id: heartbeatRuns.id, status: heartbeatRuns.status })
+          .from(heartbeatRuns).where(inArray(heartbeatRuns.id, validIds));
+        for (const row of rows) states.set(row.id, isHeartbeatRunTerminalStatus(row.status) ? "terminal" : "active");
+        return states;
+      },
+    }).then((swept) => {
+      if (swept.removed.length > 0) logger.info({ removed: swept.removed.length, truncated: swept.truncated }, "swept orphaned run scratch directories");
+    }).catch(error => {
+      logger.warn({ err: error }, "failed to sweep orphaned run scratch directories");
+    });
+
     // Complete persisted native results before generic orphan recovery. The
     // reconciler reads the durable workspace barrier and persisted runtime
     // mode, never the current feature flag.
diff --git a/server/src/services/run-scratch.test.ts b/server/src/services/run-scratch.test.ts
index a6e54aa8569..d84f82a83f1 100644
--- a/server/src/services/run-scratch.test.ts
+++ b/server/src/services/run-scratch.test.ts
@@ -7,7 +7,9 @@ import {
   buildHeartbeatRunScratchEnv,
   cleanupHeartbeatRunScratch,
   prepareHeartbeatRunScratch,
+  sweepOrphanedRunScratch,
   type HeartbeatRunScratch,
+  type RunScratchSweepRunState,
 } from "./run-scratch.js";
 
 const cleanupDirs = new Set<string>();
@@ -123,3 +125,112 @@ describe("heartbeat run scratch cleanup", () => {
     expect(result.tempKeysApplied).toEqual(["TEMP", "TMP"]);
   });
 });
+
+describe("orphaned run scratch sweep", () => {
+  async function makeRoot() {
+    const root = await fs.mkdtemp(path.join(os.tmpdir(), "paperclip-sweep-test-"));
+    cleanupDirs.add(root);
+    return root;
+  }
+  async function leave(root: string, runId: string, createdAt = new Date().toISOString()) {
+    const dir = await fs.mkdtemp(path.join(root, `paperclip-run-x-${runId}-`));
+    await fs.writeFile(
+      path.join(dir, HEARTBEAT_RUN_SCRATCH_MARKER),
+      JSON.stringify({ version: 1, companyId: "c", agentId: "a", runId, issueId: null, issueIdentifier: null, createdAt }),
+    );
+    return dir;
+  }
+  const exists = (p: string) => fs.stat(p).then(() => true, () => false);
+  const states = (m: Record<string, RunScratchSweepRunState>) => async (ids: string[]) =>
+    new Map(ids.map((id) => [id, m[id] ?? "missing"] as const));
+
+  it("removes leftover attempt dirs of a terminal run, keeps active and unmarked dirs", async () => {
+    const root = await makeRoot();
+    const killedA = await leave(root, "run-done");
+    const killedB = await leave(root, "run-done");
+    const active = await leave(root, "run-live");
+    const unmarked = await fs.mkdtemp(path.join(root, "paperclip-run-x-nomarker-"));
+    const foreign = await fs.mkdtemp(path.join(root, "other-"));
+
+    const result = await sweepOrphanedRunScratch({
+      tmpRoot: root,
+      resolveRunStates: states({ "run-done": "terminal", "run-live": "active" }),
+    });
+
+    expect(result.removed.sort()).toEqual([killedA, killedB].sort());
+    expect(await exists(killedA)).toBe(false);
+    expect(await exists(killedB)).toBe(false);
+    expect(await exists(active)).toBe(true);
+    expect(await exists(unmarked)).toBe(true);
+    expect(await exists(foreign)).toBe(true);
+  });
+
+  it("limits a per-run sweep to that run", async () => {
+    const root = await makeRoot();
+    const a = await leave(root, "run-a");
+    const b = await leave(root, "run-b");
+    await sweepOrphanedRunScratch({
+      tmpRoot: root,
+      runId: "run-a",
+      resolveRunStates: states({ "run-a": "terminal", "run-b": "terminal" }),
+    });
+    expect(await exists(a)).toBe(false);
+    expect(await exists(b)).toBe(true);
+  });
+
+  it("keeps dirs whose run this instance cannot see, however old", async () => {
+    const root = await makeRoot();
+    const foreignRun = await leave(root, "run-other-instance", new Date(Date.now() - 48 * 3600_000).toISOString());
+    await sweepOrphanedRunScratch({ tmpRoot: root, resolveRunStates: states({}) });
+    expect(await exists(foreignRun)).toBe(true);
+  });
+
+  it("reaches orphans past the scan limit on repeated sweeps", async () => {
+    const root = await makeRoot();
+    const kept = [await leave(root, "run-keep1"), await leave(root, "run-keep2")];
+    const orphan = await leave(root, "run-zzorphan");
+    const resolveRunStates = states({ "run-keep1": "active", "run-keep2": "active", "run-zzorphan": "terminal" });
+    for (let i = 0; i < 3 && (await exists(orphan)); i += 1) {
+      await sweepOrphanedRunScratch({ tmpRoot: root, maxScan: 2, resolveRunStates });
+    }
+    expect(await exists(orphan)).toBe(false);
+    expect(await exists(kept[0]!)).toBe(true);
+    expect(await exists(kept[1]!)).toBe(true);
+  });
+
+  it("finds a run's dirs for a per-run sweep regardless of unrelated entries", async () => {
+    const root = await makeRoot();
+    for (let i = 0; i < 4; i += 1) await leave(root, `run-other${i}`);
+    const target = await leave(root, "run-target");
+    await sweepOrphanedRunScratch({
+      tmpRoot: root,
+      runId: "run-target",
+      maxScan: 1,
+      resolveRunStates: states({ "run-target": "terminal" }),
+    });
+    expect(await exists(target)).toBe(false);
+  });
+
+  it("does not follow symlinks and bounds removals per sweep", async () => {
+    const root = await makeRoot();
+    const outside = await fs.mkdtemp(path.join(os.tmpdir(), "paperclip-sweep-outside-"));
+    cleanupDirs.add(outside);
+    await fs.writeFile(
+      path.join(outside, HEARTBEAT_RUN_SCRATCH_MARKER),
+      JSON.stringify({ version: 1, companyId: "c", agentId: "a", runId: "run-t", createdAt: new Date().toISOString() }),
+    );
+    await fs.symlink(outside, path.join(root, "paperclip-run-x-link"));
+    const dirs = [await leave(root, "run-t"), await leave(root, "run-t"), await leave(root, "run-t")];
+
+    const result = await sweepOrphanedRunScratch({
+      tmpRoot: root,
+      maxRemove: 2,
+      resolveRunStates: states({ "run-t": "terminal" }),
+    });
+
+    expect(await exists(outside)).toBe(true);
+    expect(result.removed).toHaveLength(2);
+    expect(result.truncated).toBe(true);
+    expect((await Promise.all(dirs.map(exists))).filter(Boolean)).toHaveLength(1);
+  });
+});
diff --git a/server/src/services/run-scratch.ts b/server/src/services/run-scratch.ts
index 1ade7abfbc8..a8152604f5d 100644
--- a/server/src/services/run-scratch.ts
+++ b/server/src/services/run-scratch.ts
@@ -1,3 +1,4 @@
+import type { Dirent } from "node:fs";
 import fs from "node:fs/promises";
 import os from "node:os";
 import path from "node:path";
@@ -158,3 +159,116 @@ export async function cleanupHeartbeatRunScratch(input: {
   await fs.rm(dir, { recursive: true, force: true });
   return { removed: true, dir };
 }
+
+/** "unknown" means this instance cannot establish ownership; it is never removed. */
+export type RunScratchSweepRunState = "terminal" | "active" | "unknown";
+
+export interface SweepRunScratchResult {
+  scanned: number;
+  removed: string[];
+  kept: number;
+  truncated: boolean;
+}
+
+export const RUN_SCRATCH_SWEEP_MAX_SCAN = 500;
+export const RUN_SCRATCH_SWEEP_MAX_REMOVE = 100;
+
+// Instances with separate databases share the temp root, so a run absent from
+// this instance's database may belong to another live instance. Keep those.
+let sweepCursor = 0;
+
+/**
+ * Remove leftover run scratch directories whose owning run is terminal (or
+ * whose run row is long gone). Earlier process attempts of a run that crossed
+ * a restart leave directories that the live attempt's cleanup never sees.
+ *
+ * Safety: only real (non-symlink) `paperclip-run-*` directories directly under
+ * the temp root, with a valid regular-file marker, are considered. Active runs
+ * and unmarked directories are always kept. Work per sweep is bounded.
+ */
+export async function sweepOrphanedRunScratch(input: {
+  resolveRunStates: (runIds: string[]) => Promise<Map<string, RunScratchSweepRunState>>;
+  /** Restrict the sweep to one run's directories (used when that run ends). */
+  runId?: string;
+  tmpRoot?: string;
+  maxScan?: number;
+  maxRemove?: number;
+}): Promise<SweepRunScratchResult> {
+  const tmpRoot = path.resolve(input.tmpRoot ?? os.tmpdir());
+  const maxScan = input.maxScan ?? RUN_SCRATCH_SWEEP_MAX_SCAN;
+  const maxRemove = input.maxRemove ?? RUN_SCRATCH_SWEEP_MAX_REMOVE;
+  const result: SweepRunScratchResult = { scanned: 0, removed: [], kept: 0, truncated: false };
+
+  let entries: Dirent[];
+  try {
+    entries = await fs.readdir(tmpRoot, { withFileTypes: true });
+  } catch {
+    return result;
+  }
+
+  // A per-run sweep pre-filters by the run segment of the directory name, so it
+  // is not limited by unrelated entries. A global sweep rotates its start so
+  // entries that are always kept cannot starve later ones.
+  const runNeedle = input.runId !== undefined
+    ? `-${sanitizePathSegment(input.runId.slice(0, 12), "run")}-`
+    : null;
+  const named = entries
+    .filter((entry) =>
+      entry.name.startsWith("paperclip-run-") && entry.isDirectory() && !entry.isSymbolicLink() &&
+      (runNeedle === null || entry.name.includes(runNeedle)))
+    .sort((a, b) => (a.name < b.name ? -1 : 1));
+  const start = runNeedle === null && named.length > 0 ? sweepCursor % named.length : 0;
+  const candidates: Array<{ dir: string; marker: HeartbeatRunScratchMetadata }> = [];
+  for (let i = 0; i < named.length; i += 1) {
+    const entry = named[(start + i) % named.length]!;
+    if (runNeedle === null && result.scanned >= maxScan) {
+      result.truncated = true;
+      sweepCursor = start + i;
+      break;
+    }
+    result.scanned += 1;
+    const dir = path.join(tmpRoot, entry.name);
+    try {
+      const markerPath = path.join(dir, HEARTBEAT_RUN_SCRATCH_MARKER);
+      const markerStat = await fs.lstat(markerPath);
+      if (!markerStat.isFile()) {
+        result.kept += 1;
+        continue;
+      }
+      const marker = await readMarker(markerPath);
+      if (!marker || (input.runId !== undefined && marker.runId !== input.runId)) {
+        result.kept += 1;
+        continue;
+      }
+      candidates.push({ dir, marker });
+    } catch {
+      result.kept += 1;
+    }
+  }
+  if (runNeedle === null && !result.truncated) sweepCursor = 0;
+  if (candidates.length === 0) return result;
+
+  const states = await input.resolveRunStates([...new Set(candidates.map((c) => c.marker.runId))]);
+  for (const { dir, marker } of candidates) {
+    const state = states.get(marker.runId) ?? "active";
+    const removable = state === "terminal";
+    if (!removable || result.removed.length >= maxRemove) {
+      if (removable) result.truncated = true;
+      result.kept += 1;
+      continue;
+    }
+    try {
+      // Re-check just before removal: never remove through a swapped symlink.
+      const stat = await fs.lstat(dir);
+      if (!stat.isDirectory() || stat.isSymbolicLink()) {
+        result.kept += 1;
+        continue;
+      }
+      await fs.rm(dir, { recursive: true, force: true });
+      result.removed.push(dir);
+    } catch {
+      result.kept += 1;
+    }
+  }
+  return result;
+}