diff --git a/CHANGELOG.md b/CHANGELOG.md
index 393a5583a1b..94d52c0e37b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -480,6 +480,7 @@ Docs: https://docs.openclaw.ai
 - Doctor/plugins: discover doctor contracts from load-path channel plugins during `openclaw doctor --fix`, so plugin-owned legacy config repair runs before validation. (#77477) Thanks @jalehman.
 - Dependencies: bump transitive `basic-ftp` to 5.3.1 so the runtime lockfile no longer includes the vulnerable 5.3.0 build flagged by the production dependency audit. (#78637) Thanks @sallyom.
 - Agents/compaction: clamp compaction summary reserve tokens to each model's output limit so high-context compaction no longer requests invalid `max_tokens` values. (#54392) Thanks @adzendo.
+- Agents/subagents: have completed session-mode subagent registry rows honor `agents.defaults.subagents.archiveAfterMinutes` (default 60 minutes; same knob run-mode already uses for `archiveAtMs`) instead of a hardcoded 5-minute TTL, so `subagents list` and other registry-backed surfaces still show recently-completed runs and operators have one consistent retention knob across spawn modes. (#78263) Thanks @arniesaha.
 
 ## 2026.5.3-1
 
diff --git a/src/agents/subagent-registry.test.ts b/src/agents/subagent-registry.test.ts
index 5a263580717..654f8511c4a 100644
--- a/src/agents/subagent-registry.test.ts
+++ b/src/agents/subagent-registry.test.ts
@@ -893,6 +893,14 @@ describe("subagent registry seam flow", () => {
 
   it("passes stored agentDir through swept context-engine cleanup paths", async () => {
     const now = Date.parse("2026-03-24T12:00:00Z");
+    // Session-mode reaping now honors agents.defaults.subagents.archiveAfterMinutes
+    // (same knob run-mode uses for archiveAtMs). The default-config mock above sets
+    // archiveAfterMinutes: 0, which disables session-mode reaping; opt this test
+    // into a real retention window so the swept-cleanup path still fires.
+    mocks.getRuntimeConfig.mockReturnValueOnce({
+      agents: { defaults: { subagents: { archiveAfterMinutes: 1 } } },
+      session: { mainKey: "main", scope: "per-sender" as const },
+    });
     mod.addSubagentRunForTests({
       runId: "run-session-swept-context-engine",
       childSessionKey: "agent:alt:session:child-session",
diff --git a/src/agents/subagent-registry.ts b/src/agents/subagent-registry.ts
index e8dcec65420..a9eb2da494f 100644
--- a/src/agents/subagent-registry.ts
+++ b/src/agents/subagent-registry.ts
@@ -36,6 +36,7 @@ import {
   reconcileOrphanedRestoredRuns,
   reconcileOrphanedRun,
   resolveAnnounceRetryDelayMs,
+  resolveArchiveAfterMs,
   resolveSubagentRunOrphanReason,
   resolveSubagentSessionStatus,
   safeRemoveAttachmentsDir,
@@ -196,8 +197,6 @@ const LIFECYCLE_ERROR_RETRY_GRACE_MS = 15_000;
  * `timed out` completion right before the eventual success.
  */
 const LIFECYCLE_TIMEOUT_RETRY_GRACE_MS = 15_000;
-/** Absolute TTL for session-mode runs after cleanup completes (no archiveAtMs). */
-const SESSION_RUN_TTL_MS = 5 * 60_000; // 5 minutes
 /** Absolute TTL for orphaned pendingLifecycleError / pendingLifecycleTimeout entries. */
 const PENDING_LIFECYCLE_TERMINAL_TTL_MS = 5 * 60_000; // 5 minutes
 /** Grace period before treating a "running" subagent without a live run context as stale. */
@@ -751,6 +750,7 @@ async function sweepSubagentRuns() {
   try {
     const now = Date.now();
     const storeCache = new Map<string, Record<string, SessionEntry>>();
+    const sessionRetentionMs = resolveArchiveAfterMs(subagentRegistryDeps.getRuntimeConfig());
     let mutated = false;
     for (const [runId, entry] of subagentRuns.entries()) {
       if (typeof entry.endedAt !== "number") {
@@ -813,12 +813,18 @@ async function sweepSubagentRuns() {
         }
       }
 
-      // Session-mode runs have no archiveAtMs — apply absolute TTL after cleanup completes.
+      // Session-mode runs have no archiveAtMs because the child session is retained
+      // independently — but the registry row itself still needs to be reaped after
+      // cleanup, otherwise `subagents list` and other registry-backed surfaces grow
+      // without bound. Honor the same `agents.defaults.subagents.archiveAfterMinutes`
+      // window run-mode uses for `archiveAtMs`, so operators get one consistent
+      // retention knob (default 60 minutes; 0 disables session-mode reaping).
       // Use cleanupCompletedAt (not endedAt) to avoid interrupting deferred cleanup flows.
       if (!entry.archiveAtMs) {
         if (
+          typeof sessionRetentionMs === "number" &&
           typeof entry.cleanupCompletedAt === "number" &&
-          now - entry.cleanupCompletedAt > SESSION_RUN_TTL_MS
+          now - entry.cleanupCompletedAt > sessionRetentionMs
         ) {
           clearPendingLifecycleError(runId);
           void notifyContextEngineSubagentEnded({