[FEATURE]: Add skills.exclude config to disable specific skill directories #26424

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Describe the enhancement you want to request

Problem

OpenCode scans 6 standard skill directories (global + project-level):

• ~/.config/opencode/skills//SKILL.md
• ~/.claude/skills//SKILL.md
• ~/.agents/skills//SKILL.md
• .opencode/skills//SKILL.md
• .claude/skills//SKILL.md
• .agents/skills//SKILL.md

Users may want to exclude specific directories (e.g., ~/.agents/skills/) while keeping others (e.g., ~/.claude/skills/). Currently there is no selective exclusion mechanism — either all global directories are scanned, or none via OPENCODE_DISABLE_GLOBAL_CONFIG.

Proposed Solution

Add a skills.exclude config option in opencode.json:

{
  skills: {
    exclude: [~/.agents/skills]
  }
}

Behavior:

• Accepts an array of directory paths (supports ~ expansion)
• Paths are checked against skill directory roots
• Matching directories are skipped during discovery
• Other directories remain unaffected

Why This Matters

• Users with large skill collections in ~/.agents/skills/ may want to limit noise in the available skills list
• GSD framework users have internal skills that should not appear in agent selection
• permission.skill: deny blocks programmatic spawning (via task tool), which is too restrictive

Related

• OPENCODE_DISABLE_GLOBAL_CONFIG (PR feat(config): add OPENCODE_DISABLE_GLOBAL_CONFIG flag #21650) — all-or-nothing global disable
• hidden: true frontmatter (issues [FEATURE]: Add hidden field to skill frontmatter to exclude skills from agent selection #20473/[FEATURE]: Add hidden field to skill frontmatter to exclude skills from agent selection #20474) — per-skill hiding (not yet merged)