Global skills in ~/.config/opencode/skills/ and project .opencode/skills/ not discovered in Desktop 1.18.27 (only external ~/.agents skills load)

Description

In OpenCode Desktop 1.18.27 (latest release, 2026-09-02) on Linux, custom skills placed in ~/.config/opencode/skills/<name>/SKILL.md (global) or .opencode/skills/<name>/SKILL.md (project) are not discovered. Only external skills from ~/.agents/skills/**/SKILL.md and the built-in customize-opencode are available to the model.

Verified facts:

• SKILL.md files are valid: frontmatter has name + description, name matches directory name, filename is all-caps, unique names.
• Desktop was fully restarted after creating the skills.
• Calling the skill tool returns: Skill "<name>" not found. Available skills: capacity, customize, customize-opencode, deploy-model, microsoft-foundry, preset (exactly the ~/.agents external skills + built-in).
• Server log on Desktop startup shows init count=6, while CLI opencode run (v1.18.23) on the same machine logs init count=12 (all skills including c-standards, python-standards, design-docs, doc-style, review-checklist, test-approach).

Related to #46781 and #45961 / #46298.

Analysis

In packages/opencode/src/skill/index.ts, discoverSkills() does:

1. External scans (~/.agents, ~/.claude) pass a scope option to scan() — glob failures are logged and skipped gracefully.
2. Config-dir scans (config.directories() — global ~/.config/opencode, project .opencode dirs) call scan(state, dir, "{skill,skills}/**/SKILL.md") without scope. Any glob failure calls Effect.die(error), which kills the entire discovery pass. The external skills that were already added survive; config skills are silently lost.

PR #46298 ("don't crash skill discovery on unscoped scan errors") fixes exactly this path but was closed without being merged into dev (the last commit touching skill/index.ts in dev is 2026-06-30). The bug is still present in the v1.18.27 tag: if (!opts?.scope) return Effect.die(error).

The exact glob error is not visible in logs (nothing is logged before the crash), but the code path matches the symptom 1:1: external skills load first and survive, config skills never appear.

Steps to reproduce

1. Create ~/.config/opencode/skills/demo/SKILL.md with valid frontmatter (name/description).
2. Start Desktop 1.18.27.
3. Ask the model to load skill demo — returns Skill "demo" not found.

Workaround

Adding explicit paths to config bypasses the config-dir scan branch:

"skills": { "paths": ["~/.config/opencode/skills"] }

(requires Desktop restart; applied and pending verification).

Environment

• OpenCode Desktop 1.18.27 (latest, 2026-09-02)
• Linux (Debian trixie), x86_64
• CLI opencode 1.18.23 works correctly on the same machine