[BUG]: external .claude/.agents skill discovery silently finds nothing (global and project) in 1.18.15 #41213

Description

Skill discovery from the external .claude / .agents directories silently finds nothing in v1.18.15. Both legs implemented in discoverSkills are affected:

• global: ~/.claude/skills/**/SKILL.md and ~/.agents/skills/**/SKILL.md
• project: the same targets found by walking up from the session directory

opencode's own directories (~/.config/opencode/skills/...) still work, so the failure is specific to the external branch. No error is surfaced — the skills are simply absent from /api/skill and from the skill tool.

This looks like a regression. #31977 (2026-06-12) shows external discovery working well enough to produce duplicate-name warnings from .claude/skills + .agents/skills; on v1.18.15 those same directories yield zero skills.

Steps to reproduce

Fully isolated, no dependency on my machine's config:

# fixture: an external skill in both a fake HOME and a project dir
rm -rf /tmp/ocrepro && mkdir -p /tmp/ocrepro/home/.agents/skills/probe-global \
                                /tmp/ocrepro/home/.config/opencode/skills/probe-control \
                                /tmp/ocrepro/proj/.agents/skills/probe-project

printf -- '---\nname: probe-global\ndescription: external global probe\n---\nbody\n'  > /tmp/ocrepro/home/.agents/skills/probe-global/SKILL.md
printf -- '---\nname: probe-control\ndescription: opencode-dir control\n---\nbody\n'  > /tmp/ocrepro/home/.config/opencode/skills/probe-control/SKILL.md
printf -- '---\nname: probe-project\ndescription: external project probe\n---\nbody\n'> /tmp/ocrepro/proj/.agents/skills/probe-project/SKILL.md

cd /tmp/ocrepro/proj
HOME=/tmp/ocrepro/home opencode serve --hostname=127.0.0.1 --port=47990 &
sleep 20
curl -s "http://127.0.0.1:47990/api/skill?directory=/tmp/ocrepro/proj" | jq -r '.data[].name'

Expected

probe-global, probe-project and probe-control all listed.

Actual

Only probe-control (plus the built-in customize-opencode). Both external probes are missing.

What I ruled out

• Not the disable flags. disableExternalSkills / disableClaudeCodeSkills both default to false in runtime-flags.ts. Setting OPENCODE_DISABLE_EXTERNAL_SKILLS=false and OPENCODE_DISABLE_CLAUDE_CODE_SKILLS=false explicitly changes nothing.
• Not the glob pattern or options. Running the exact call from Glob.scan outside opencode finds the fixtures:

  await glob("skills/**/SKILL.md", { cwd: "<home>/.agents", absolute: true, dot: true, follow: true, nodir: true })
  // -> [ '<home>/.agents/skills/probe-global/SKILL.md' ]

• Not home resolution. Same result with OPENCODE_TEST_HOME pointed at the fixture instead of HOME.
• Not frontmatter. The control skill uses byte-identical frontmatter and is discovered.
• Not symlinks. The fixtures are real directories.

Since scan() swallows and logs errors when opts.scope is set (which is exactly the external branch, and only the external branch), a throw inside that scan would produce precisely this silent-empty behaviour — that seems the most likely place to look, though I could not confirm it from the logs.

Impact

This is the documented way to share one canonical skills directory across Claude Code / Codex / opencode, so those setups quietly lose every skill.

It is especially hard to work around inside T3 Code, which spawns opencode serve with OPENCODE_CONFIG_CONTENT={}. That discards the user's opencode.json, so the usual skills.paths escape hatch is unavailable there — the external directories are the only remaining mechanism, and they don't work.

Workaround: symlink each skill into ~/.config/opencode/skills/<name>, which is scanned by a different code path and works.

Environment

• opencode 1.18.15 (latest at time of filing; installed via the native installer)
• macOS 15 / darwin arm64