[FEATURE]: Add a switch to disable automatic skill directory discovery #15396

Feature hasn't been suggested before.

• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

OpenCode currently auto-loads skills from several directories, including project and global locations (.opencode/skills, ~/.config/opencode/skills, .claude/skills, ~/.claude/skills, .agents/skills, and ~/.agents/skills).

I use OpenCode alongside other tools and need stricter control over what gets loaded. Please add a single config/env option that disables directory-based skill auto-discovery, so skills are only loaded when explicitly configured.

A couple possible interfaces:

{
  "skills": {
    "auto_discovery": false
  }
}

Or an env var such as:

OPENCODE_DISABLE_SKILL_AUTO_DISCOVERY=1

Why this would help:

• Prevents cross-tool skill leakage into OpenCode
• Avoids accidentally loading incompatible SKILL.md files
• Makes behavior predictable in shared repos, CI, and automation

Related issues I checked:

• Feature Request: Add configuration option to disable automatic Claude Code skills/commands sync #12604 (closed: Claude compatibility sync toggle)
• OPENCODE_DISABLE_CLAUDE_CODE=1 also disable .agents/skills added in v1.1.50 #12432 (open: disable flag side effects)
• Feature Request: Configurable skills search paths & TUI settings management #11189 (open: configurable search paths)

Those are related, but I could not find one that asks for a global "do not auto-load skills from any directory" switch.