TUI startup hang/high CPU on macOS when external skills contain symlink cycle

[ckken]

Description

opencode can hang on startup with very high CPU usage on macOS when external skills contain a symlink cycle.

In my environment, launching opencode in Terminal shows no usable UI (appears frozen) and process CPU stays very high (300%+ observed), while opencode web and non-TUI commands still work.

Root cause appears to be external skill discovery traversing a symlink loop:

• /Users/bigo/.emp-agent/skills/empjs -> /Users/bigo/Desktop/Develop/emp-workspace/emp/skills/empjs
• inside that folder, subpaths point back to ~/.emp-agent/skills/empjs:
  • .agent/skills/empjs -> /Users/bigo/.emp-agent/skills/empjs
  • .agents/skills/empjs -> /Users/bigo/.emp-agent/skills/empjs
  • .shared/skills/empjs -> /Users/bigo/.emp-agent/skills/empjs

With this structure, TUI startup hangs/high-CPU. If I disable external skills, it starts normally.

Plugins

None (user config plugin: []; only internal defaults)

OpenCode version

1.2.17

Steps to reproduce

1. Ensure there is a symlink cycle in external skills paths (example pattern above).
2. Run opencode (TUI) in Terminal.
3. Observe startup appears stuck and .opencode process uses very high CPU for a long time.
4. Run with workaround:
   • OPENCODE_DISABLE_EXTERNAL_SKILLS=1 opencode
5. Observe TUI starts immediately and CPU usage is normal.

Screenshot and/or share link

No screenshot; command evidence from local debug:

• lsof -p <opencode_pid> shows skill directories/symlinked paths being traversed.
• sample <pid> during hang shows the process busy in repeated filesystem traversal/open calls.

Operating System

macOS 26.2 (arm64)

Terminal

Apple Terminal

---

Suggested fix ideas:

• During skills discovery, avoid following symlinks recursively by default; or
• Track visited inode/realpath to break cycles; and
• Skip known transient skill helper directories like .agent, .agents, .shared if they are not intended as user skill roots.

Current workaround (works reliably):

• OPENCODE_DISABLE_EXTERNAL_SKILLS=1 opencode

[coffeepenbit]

I was having a very similar issue. I created a PR to address it #18670