v1.2.9: MCP Attachment Fix, Performance Optimization
Release Date: 2026-02-20
This version fixes the issue of missing IDs in MCP tool attachments, and includes several performance optimizations.
🎯 One-Sentence Summary
Fixed MCP tool attachment ID missing issue; use native structuredClone for better performance; desktop restored settings header mask.
🐛 Bug Fixes
MCP Tool Attachment ID Fix
MCP tool attachments now include correct id, sessionID, and messageID.
Impact: Previously, some attachments returned by MCP tools might not be correctly associated with sessions; now fixed.
⚡ Performance Optimizations
Using Native structuredClone
TUI now uses JavaScript's native structuredClone instead of remeda library's clone function.
Benefits: Better performance and native support.
Removed Unnecessary Deep Clones
Removed unnecessary deep clone operations from session loop and LLM stream, improving processing speed.
Test Fix
Removed User-Agent assertion from LLM tests, fixing test failure issues.
🖥️ Desktop Updates
Restored Settings Header Mask
Restored the settings interface header mask display in desktop.
📊 Should You Upgrade?
| Situation | Recommendation |
|---|---|
| Using MCP tools | ✅ Recommended |
| Care about performance | ✅ Recommended |
| Everything works fine | ⚪ Optional upgrade |
⬆️ Upgrade Command
opencode upgrade📋 Technical Details
Click to expand original Release Notes
Core
- Add missing id, sessionID, and messageID to MCP tool attachments (@NatChung)
- Remove unnecessary deep clones from session loop and LLM stream
- Remove User-Agent header assertion from LLM test to fix failing test
TUI
- Use structuredClone instead of remeda's clone for better performance and native support (@mhart)
Desktop
- Restore settings header mask
Thank you to 2 community contributors:
- @mhart: Use structuredClone instead of remeda's clone
- @NatChung: fix: add missing id/sessionID/messageID to MCP tool attachments