From 2e5550128c6cd1409d562bafcb06aae53e486db1 Mon Sep 17 00:00:00 2001
From: antfleet-ops <285575208+antfleet-ops@users.noreply.github.com>
Date: Fri, 19 Jun 2026 10:23:08 +0300
Subject: [PATCH] Preserve local ACP config across interrupted writes

Constraint: fix must avoid changing config schema or keychain behavior.\nRejected: direct write to CONFIG_PATH | leaves partial JSON on interruption.\nConfidence: high\nScope-risk: narrow\nDirective: keep future config persistence rename-based or stronger; do not reintroduce truncate-in-place writes.\nTested: npm run typecheck; npm run build\nNot-tested: fsync durability across OS crash.
---
 src/lib/config.ts | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/src/lib/config.ts b/src/lib/config.ts
index 863aced..e96f518 100644
--- a/src/lib/config.ts
+++ b/src/lib/config.ts
@@ -1,4 +1,4 @@
-import { existsSync, mkdirSync, readFileSync, renameSync, writeFileSync } from "fs";
+import { existsSync, mkdirSync, readFileSync, renameSync, rmSync, writeFileSync } from "fs";
 import { homedir } from "os";
 import { resolve } from "path";
 import {
@@ -59,7 +59,20 @@ function loadConfig(): Config {
 
 function saveConfig(config: Config): void {
   mkdirSync(CONFIG_DIR, { recursive: true });
-  writeFileSync(CONFIG_PATH, JSON.stringify(config, null, 2) + "\n");
+  const tempPath = `${CONFIG_PATH}.${process.pid}.${Date.now()}.tmp`;
+  try {
+    writeFileSync(tempPath, JSON.stringify(config, null, 2) + "\n", {
+      mode: 0o600,
+    });
+    renameSync(tempPath, CONFIG_PATH);
+  } catch (err) {
+    try {
+      rmSync(tempPath, { force: true });
+    } catch {
+      // best effort cleanup
+    }
+    throw err;
+  }
 }
 
 function isKeychainUnavailable(err: unknown): boolean {