fix: preserve plugin maintenance config compatibility

src/config/sessions/store-maintenance.ts

@@ -47,6 +47,12 @@ export type ResolvedSessionMaintenanceConfig = {
   highWaterBytes: number | null;
 };
 
+export type ResolvedSessionMaintenanceConfigInput = Omit<
+  ResolvedSessionMaintenanceConfig,
+  "modelRunPruneAfterMs"
+> &
+  Partial<Pick<ResolvedSessionMaintenanceConfig, "modelRunPruneAfterMs">>;
+
 function resolvePruneAfterMs(maintenance?: SessionMaintenanceConfig): number {
   const raw = maintenance?.pruneAfter ?? maintenance?.pruneDays;
   const normalized = normalizeStringifiedOptionalString(raw);
@@ -147,6 +153,15 @@ export function resolveMaintenanceConfigFromInput(
   };
 }
 
+export function normalizeResolvedMaintenanceConfigInput(
+  maintenance: ResolvedSessionMaintenanceConfigInput,
+): ResolvedSessionMaintenanceConfig {
+  return {
+    ...maintenance,
+    modelRunPruneAfterMs: maintenance.modelRunPruneAfterMs ?? DEFAULT_MODEL_RUN_PRUNE_AFTER_MS,
+  };
+}
+
 export function resolveSessionEntryMaintenanceHighWater(maxEntries: number): number {
   if (!Number.isSafeInteger(maxEntries) || maxEntries <= 0) {
     return 1;

src/config/sessions/store.ts

@@ -69,6 +69,7 @@ import {
   pruneStaleModelRunEntries,
   pruneStaleEntries,
   type ResolvedSessionMaintenanceConfig,
+  type ResolvedSessionMaintenanceConfigInput,
   type SessionMaintenanceWarning,
 } from "./store-maintenance.js";
 import { runExclusiveSessionStoreWrite } from "./store-writer.js";
@@ -173,7 +174,11 @@ export {
   resolveMaintenanceConfig,
 };
 export type { SessionMaintenanceApplyReport } from "./store-maintenance-operations.js";
-export type { ResolvedSessionMaintenanceConfig, SessionMaintenanceWarning };
+export type {
+  ResolvedSessionMaintenanceConfig,
+  ResolvedSessionMaintenanceConfigInput,
+  SessionMaintenanceWarning,
+};
 
 type SaveSessionStoreOptions = {
   /** Skip pruning, capping, and rotation (e.g. during one-time migrations). */

src/plugin-sdk/session-store-runtime.test.ts

@@ -165,6 +165,51 @@ describe("session-store-runtime compatibility surface", () => {
     expect(getSessionEntry({ sessionKey: staleSessionKey, storePath })).toBeUndefined();
   });
 
+  it("accepts pre-model-run maintenance configs through entry patches", async () => {
+    const staleModelRunKey = "agent:main:explicit:model-run-123e4567-e89b-12d3-a456-426614174000";
+    const activeSessionKey = "agent:main:active";
+    const now = Date.now();
+    await saveSessionStore(
+      storePath,
+      {
+        [staleModelRunKey]: {
+          sessionId: "session-probe",
+          updatedAt: now - 2 * DAY_MS,
+        },
+        [activeSessionKey]: {
+          sessionId: "session-active",
+          updatedAt: now,
+        },
+      },
+      { skipMaintenance: true },
+    );
+
+    const legacyMaintenanceConfig = {
+      mode: "enforce" as const,
+      pruneAfterMs: 7 * DAY_MS,
+      maxEntries: 500,
+      resetArchiveRetentionMs: 7 * DAY_MS,
+      maxDiskBytes: null,
+      highWaterBytes: null,
+    };
+
+    await expect(
+      patchSessionEntry({
+        sessionKey: activeSessionKey,
+        storePath,
+        maintenanceConfig: legacyMaintenanceConfig,
+        update: () => ({ model: "gpt-5.5" }),
+      }),
+    ).resolves.toMatchObject({
+      model: "gpt-5.5",
+      sessionId: "session-active",
+    });
+
+    expect(getSessionEntry({ sessionKey: staleModelRunKey, storePath })).toMatchObject({
+      sessionId: "session-probe",
+    });
+  });
+
   it("keeps deprecated whole-store mutations grouped as one compatibility operation", async () => {
     const firstSessionKey = "agent:main:first";
     const secondSessionKey = "agent:main:second";

src/plugin-sdk/session-store-runtime.ts

@@ -12,7 +12,8 @@ import {
   updateSessionEntry,
 } from "../config/sessions/session-accessor.js";
 import { loadSessionStore as loadSessionStoreImpl } from "../config/sessions/store-load.js";
-import type { ResolvedSessionMaintenanceConfig } from "../config/sessions/store.js";
+import { normalizeResolvedMaintenanceConfigInput } from "../config/sessions/store-maintenance.js";
+import type { ResolvedSessionMaintenanceConfigInput } from "../config/sessions/store.js";
 import type { SessionEntry } from "../config/sessions/types.js";
 
 type SessionStoreReadParams = {
@@ -42,7 +43,7 @@ type SessionStoreEntryPatch = (
 
 type PatchSessionEntryParams = SessionStoreReadParams & {
   fallbackEntry?: SessionEntry;
-  maintenanceConfig?: ResolvedSessionMaintenanceConfig;
+  maintenanceConfig?: ResolvedSessionMaintenanceConfigInput;
   preserveActivity?: boolean;
   replaceEntry?: boolean;
   update: SessionStoreEntryPatch;
@@ -128,7 +129,10 @@ export async function patchSessionEntry(
 ): Promise<SessionEntry | null> {
   return await patchAccessorSessionEntry(toSessionAccessScope(params), params.update, {
     fallbackEntry: params.fallbackEntry,
-    maintenanceConfig: params.maintenanceConfig,
+    maintenanceConfig:
+      params.maintenanceConfig !== undefined
+        ? normalizeResolvedMaintenanceConfigInput(params.maintenanceConfig)
+        : undefined,
     preserveActivity: params.preserveActivity,
     replaceEntry: params.replaceEntry,
   });

src/plugins/runtime/runtime-agent.ts

@@ -19,11 +19,12 @@ import {
   type SessionAccessScope,
   updateSessionEntry,
 } from "../../config/sessions/session-accessor.js";
+import { normalizeResolvedMaintenanceConfigInput } from "../../config/sessions/store-maintenance.js";
 import {
   loadSessionStore,
   saveSessionStore,
   updateSessionStore,
-  type ResolvedSessionMaintenanceConfig,
+  type ResolvedSessionMaintenanceConfigInput,
 } from "../../config/sessions/store.js";
 import type { SessionEntry } from "../../config/sessions/types.js";
 import { createLazyRuntimeMethod, createLazyRuntimeModule } from "../../shared/lazy-runtime.js";
@@ -59,7 +60,7 @@ type RuntimeSessionStoreEntryUpdateParams = {
 
 type RuntimeSessionStoreEntryPatchParams = RuntimeSessionStoreReadParams & {
   fallbackEntry?: SessionEntry;
-  maintenanceConfig?: ResolvedSessionMaintenanceConfig;
+  maintenanceConfig?: ResolvedSessionMaintenanceConfigInput;
   preserveActivity?: boolean;
   replaceEntry?: boolean;
   update: (
@@ -123,7 +124,10 @@ async function patchSessionEntry(
 ): Promise<SessionEntry | null> {
   return await patchAccessorSessionEntry(toSessionAccessScope(params), params.update, {
     fallbackEntry: params.fallbackEntry,
-    maintenanceConfig: params.maintenanceConfig,
+    maintenanceConfig:
+      params.maintenanceConfig !== undefined
+        ? normalizeResolvedMaintenanceConfigInput(params.maintenanceConfig)
+        : undefined,
     preserveActivity: params.preserveActivity,
     replaceEntry: params.replaceEntry,
   });

src/plugins/runtime/types-core.ts

@@ -75,7 +75,7 @@ type RuntimeSessionStoreEntrySummary = {
 };
 type RuntimeSessionStoreEntryPatchParams = RuntimeSessionStoreReadParams & {
   fallbackEntry?: RuntimeSessionEntry;
-  maintenanceConfig?: import("../../config/sessions/store.js").ResolvedSessionMaintenanceConfig;
+  maintenanceConfig?: import("../../config/sessions/store.js").ResolvedSessionMaintenanceConfigInput;
   preserveActivity?: boolean;
   replaceEntry?: boolean;
   update: (