What's Changed

🐛 Fixes

• ⛈️ MCP Reconnection Storm Prevention with Circuit Breaker, Backoff, and Tool Stubs by @mawburn in #12162
• 🛤️ Base URL Fallback for Path-based OAuth Discovery in Token Refresh by @oreonl in #12164
• 🛂 MCP OAuth Race Conditions, CSRF Fallback, and Token Expiry Handling by @danny-avila in #12171
• 🫙 Force MeiliSearch Full Sync on Empty Index State by @danny-avila in #12202
• 🔏 MCP Server URL Schema Validation by @danny-avila in #12204
• 🪪 MCP API Responses and OAuth Validation by @danny-avila in #12217
• 🚦 Add Rate Limiting to Conversation Duplicate Endpoint by @danny-avila in #12218
• 🔐 Add User Filter to Message Deletion by @danny-avila in #12220
• 🔑 Require OTP Verification for 2FA Re-Enrollment and Backup Code Regeneration by @danny-avila in #12223
• 🛡️ Agent Permission Check on Image Upload Route by @danny-avila in #12219
• 🧹 Sanitize Artifact Filenames in Code Execution Output by @danny-avila in #12222
• 🌊 Prevent Buffered Event Duplication on SSE Resume Connections by @danny-avila in #12225
• 📎 Respect fileConfig.disabled for Agents Endpoint Upload Button by @danny-avila in #12238
• 📎 Enforce File Count and Size Limits Across All Attachment Paths by @danny-avila in #12239
• 🛰️ Cross-Replica Created Event Delivery by @danny-avila in #12231
• 🛡️ Cover full fe80::/10 link-local range in IPv6 check by @danny-avila in #12244
• 🪤 Fail-Closed MCP Domain Validation for Unparseable URLs by @danny-avila in #12245
• 🛡️ Enforce MULTI_CONVO and agent ACL checks on addedConvo by @danny-avila in #12243
• 🛡️ Validate User-provided URLs for Web Search by @danny-avila in #12247
• 🪪 Enforce VIEW ACL on Agent Edge References at Write and Runtime by @danny-avila in #12246
• 📑 Sanitize Markdown Artifacts by @danny-avila in #12249
• 🫷 Validate User-Provided Base URL in Endpoint Init by @danny-avila in #12248
• 🔏 Scope Agent-Author File Access to Attached Files Only by @danny-avila in #12251
• 🪙 Resolve Azure AD Group Overage via OBO Token Exchange for OpenID by @Airamhh in #12187
• 🔏 Enforce MCP Server Authorization on Agent Tool Persistence by @danny-avila in #12250
• 🛂 Enforce Actions Capability Gate Across All Event-Driven Tool Loading Paths by @danny-avila in #12252
• 🧱 Enforce Agent Access Control on Context and OCR File Loading by @danny-avila in #12253
• 🗝️ Exempt Admin-Trusted Domains from MCP OAuth Validation by @danny-avila in #12255
• 🧯 Prevent Env-Variable Exfil. via Placeholder Injection by @danny-avila in #12260
• 🪪 Enforce Conversation Ownership Checks in Remote Agent Controllers by @danny-avila in #12263
• 🔏 Remove Federated Tokens from OpenID Refresh Response by @danny-avila in #12264
• 🪝 MCP Refresh token on OAuth Discovery Failure by @danny-avila in #12266
• 🪢 Action Domain Encoding Collision for HTTPS URLs by @danny-avila in #12271
• 🏷️ Clear Model Spec Fields When Navigating with Non-spec Query Params by @danny-avila in #12274
• 🧯 Add Pre-Parse File Size Guard to Document Parser by @danny-avila in #12275
• 🛂 Validate types Query Param in People Picker Access Middleware by @danny-avila in #12276

🔧 Refactoring

• 🔄 OAuth Metadata Discovery with Origin Fallback by @danny-avila in #12170
• ⚡ Replace tiktoken with ai-tokenizer by @danny-avila in #12175
• 📏 Add File Size Limits to Conversation Imports by @danny-avila in #12221
• 💁 Better Config UX for MCP STDIO with customUserVars by @danny-avila in #12226
• 🛡️ Scope Action Mutations by Parent Resource Ownership by @danny-avila in #12237
• 🐍 Normalize Non-Standard Browser MIME Type Aliases in inferMimeType by @danny-avila in #12240
• 🔧 Proper MCP Menu Dismissal by @dustinhealy in #12256

⚙️ Other Changes

• 🧪 MCP Reconnect Storm Follow-Up Fixes and Integration Tests by @danny-avila in #12172
• 📦 Bump NPM Audit Packages by @danny-avila in #12227
• 📦 Bump @librechat/agents to v3.1.56 by @danny-avila in #12258

🌍 Internationalization

• 🌍 i18n: Update translation.json with latest translations by @github-actions[bot] in #12176, #12203, #12259