diff --git a/src/config/sessions/session-entry-lifecycle.test.ts b/src/config/sessions/session-entry-lifecycle.test.ts
index c482bb13788e..b1122d27c57e 100644
--- a/src/config/sessions/session-entry-lifecycle.test.ts
+++ b/src/config/sessions/session-entry-lifecycle.test.ts
@@ -52,6 +52,88 @@ describe("session entry lifecycle seam", () => {
     ).toBeUndefined();
   });
 
+  it("preserves an existing raw row key while exposing normalized context", async () => {
+    fs.writeFileSync(
+      storePath,
+      JSON.stringify({
+        GLOBAL: {
+          sessionId: "session-raw",
+          updatedAt: 10,
+        },
+      }),
+    );
+    let contextKey: string | undefined;
+
+    await patchSessionLifecycleEntry(
+      { sessionKey: "GLOBAL", storePath },
+      (entry, context) => {
+        contextKey = context.sessionKey;
+        entry.fastMode = true;
+        return entry;
+      },
+      { replaceEntry: true, skipMaintenance: true },
+    );
+
+    const store = loadSessionStore(storePath, { skipCache: true });
+    expect(contextKey).toBe("global");
+    expect(store.GLOBAL?.fastMode).toBe(true);
+    expect(store.global).toBeUndefined();
+  });
+
+  it("collapses legacy aliases when a usable canonical row exists", async () => {
+    fs.writeFileSync(
+      storePath,
+      JSON.stringify({
+        "agent:main:main": {
+          sessionId: "session-canonical",
+          updatedAt: 10,
+          fastMode: false,
+        },
+        "Agent:Main:Main": {
+          sessionId: "session-legacy",
+          updatedAt: 20,
+          fastMode: false,
+        },
+      }),
+    );
+
+    await patchSessionLifecycleEntry(
+      { sessionKey: "Agent:Main:Main", storePath },
+      (entry) => {
+        entry.fastMode = true;
+        return entry;
+      },
+      { replaceEntry: true, skipMaintenance: true },
+    );
+
+    const store = loadSessionStore(storePath, { skipCache: true });
+    expect(store["agent:main:main"]?.sessionId).toBe("session-legacy");
+    expect(store["agent:main:main"]?.fastMode).toBe(true);
+    expect(store["Agent:Main:Main"]).toBeUndefined();
+  });
+
+  it("preserves a fallback raw row key", async () => {
+    await patchSessionLifecycleEntry(
+      { sessionKey: "UNKNOWN", storePath },
+      (entry) => {
+        entry.fastMode = true;
+        return entry;
+      },
+      {
+        fallbackEntry: {
+          sessionId: "session-fallback",
+          updatedAt: 10,
+        },
+        replaceEntry: true,
+        skipMaintenance: true,
+      },
+    );
+
+    const store = loadSessionStore(storePath, { skipCache: true });
+    expect(store.UNKNOWN?.fastMode).toBe(true);
+    expect(store.unknown).toBeUndefined();
+  });
+
   it("patches multiple entries without exposing a mutable store", async () => {
     await upsertSessionEntry(
       { sessionKey: "agent:main:one", storePath },
diff --git a/src/config/sessions/session-entry-lifecycle.ts b/src/config/sessions/session-entry-lifecycle.ts
index 625e311ee5e3..4d6a258a0f2a 100644
--- a/src/config/sessions/session-entry-lifecycle.ts
+++ b/src/config/sessions/session-entry-lifecycle.ts
@@ -1,5 +1,6 @@
 import { getRuntimeConfig } from "../io.js";
 import { resolveStorePath } from "./paths.js";
+import { hasMismatchedCaseSensitiveDeliveryProof } from "./store-entry.js";
 import {
   archiveRemovedSessionTranscripts,
   loadSessionStore,
@@ -63,6 +64,11 @@ export async function patchSessionLifecycleEntry(
       if (!existing) {
         return { changed: false, entry: null };
       }
+      const storageKey = resolveLifecyclePatchStorageKey({
+        store,
+        resolved,
+        requestedKey: scope.sessionKey,
+      });
       const patch = await update(structuredClone(existing), {
         existingEntry: resolved.existing ? structuredClone(resolved.existing) : undefined,
         sessionKey: resolved.normalizedKey,
@@ -78,8 +84,11 @@ export async function patchSessionLifecycleEntry(
         : options.preserveActivity
           ? mergeSessionEntryPreserveActivity(existing, patch)
           : mergeSessionEntry(existing, patch);
-      store[resolved.normalizedKey] = next;
+      store[storageKey] = next;
       for (const legacyKey of resolved.legacyKeys) {
+        if (legacyKey === storageKey) {
+          continue;
+        }
         delete store[legacyKey];
       }
       return { changed: true, entry: next };
@@ -219,6 +228,35 @@ function collectReferencedSessionIds(store: Record<string, SessionEntry>): Set<s
   );
 }
 
+// Preserve the concrete row key for behavior-neutral file-backed updates. Callers
+// still receive the normalized key in context for canonical decisions.
+function resolveLifecyclePatchStorageKey(params: {
+  store: Record<string, SessionEntry>;
+  requestedKey: string;
+  resolved: ReturnType<typeof resolveSessionStoreEntry>;
+}): string {
+  if (
+    params.resolved.existing &&
+    params.store[params.resolved.normalizedKey] === params.resolved.existing
+  ) {
+    return params.resolved.normalizedKey;
+  }
+  const canonicalEntry = params.store[params.resolved.normalizedKey];
+  if (
+    canonicalEntry &&
+    !hasMismatchedCaseSensitiveDeliveryProof(canonicalEntry, params.resolved.normalizedKey)
+  ) {
+    return params.resolved.normalizedKey;
+  }
+  const existingLegacyKey = params.resolved.legacyKeys.find(
+    (legacyKey) => params.store[legacyKey] === params.resolved.existing,
+  );
+  if (existingLegacyKey) {
+    return existingLegacyKey;
+  }
+  return params.requestedKey.trim() || params.resolved.normalizedKey;
+}
+
 function rememberRemovedSessionFile(
   removedSessionFiles: Map<string, string | undefined>,
   entry: SessionEntry,