revert: PR 18288 accidental merge (#19224)

Merged via /review-pr -> /prepare-pr -> /merge-pr.

Prepared head SHA: 3cda31578c
Co-authored-by: sebslight <19554889+sebslight@users.noreply.github.com>
Co-authored-by: sebslight <19554889+sebslight@users.noreply.github.com>
Reviewed-by: @sebslight

CHANGELOG.md

@@ -24,6 +24,7 @@ Docs: https://docs.openclaw.ai
 ### Fixes
 
 - Agents: revert accidental per-model thinkingDefault override merge. (#19195) Thanks @sebslight.
+- Sessions: revert accidental session transcript permission hardening from PR #18288. (#19224) Thanks @sebslight.
 - Voice call/Gateway: prevent overlapping closed-loop turn races with per-call turn locking, route transcript dedupe via source-aware fingerprints with strict cache eviction bounds, and harden `voicecall latency` stats for large logs without spread-operator stack overflow. (#19140) Thanks @mbelinky.
 - iOS/Onboarding: stop auth Step 3 retry-loop churn by pausing reconnect attempts on unauthorized/missing-token gateway errors and keeping auth/pairing issue state sticky during manual retry. (#19153) Thanks @mbelinky.
 - Fix types in all tests. Typecheck the whole repository.

src/agents/pi-embedded-runner/session-manager-init.ts

@@ -43,7 +43,7 @@ export async function prepareSessionManagerForRun(params: {
 
   if (params.hadSessionFile && header && !hasAssistant) {
     // Reset file so the first assistant flush includes header+user+assistant in order.
-    await fs.writeFile(params.sessionFile, "", { encoding: "utf-8", mode: 0o600 });
+    await fs.writeFile(params.sessionFile, "", "utf-8");
     sm.fileEntries = [header];
     sm.byId?.clear?.();
     sm.labelsById?.clear?.();

src/auto-reply/reply/session.ts

@@ -89,10 +89,7 @@ function forkSessionFromParent(params: {
       cwd: manager.getCwd(),
       parentSession: parentSessionFile,
     };
-    fs.writeFileSync(sessionFile, `${JSON.stringify(header)}\n`, {
-      encoding: "utf-8",
-      mode: 0o600,
-    });
+    fs.writeFileSync(sessionFile, `${JSON.stringify(header)}\n`, "utf-8");
     return { sessionId, sessionFile };
   } catch {
     return null;

src/gateway/server-methods/sessions.ts

@@ -471,10 +471,7 @@ export const sessionsHandlers: GatewayRequestHandlers = {
 
     const archived = archiveFileOnDisk(filePath, "bak");
     const keptLines = lines.slice(-maxLines);
-    fs.writeFileSync(filePath, `${keptLines.join("\n")}\n`, {
-      encoding: "utf-8",
-      mode: 0o600,
-    });
+    fs.writeFileSync(filePath, `${keptLines.join("\n")}\n`, "utf-8");
 
     await updateSessionStore(storePath, (store) => {
       const entryKey = compactTarget.primaryKey;