OPENCODE_CONFIG_DIR overrides global AGENTS.md path instead of adding to it #28658

Setting OPENCODE_CONFIG_DIR prevents the global AGENTS.md from loading because the global instructions path and the config directory scan use different resolution strategies.

ConfigPaths.directories() in packages/opencode/src/config/paths.ts:26 always includes Global.Path.config (the static XDG path, ~/.config/opencode) in the directory list, so agents, commands, and skills from the XDG config dir are always discovered regardless of OPENCODE_CONFIG_DIR.

But instruction.ts:64 builds the global AGENTS.md path from global.config (the Service property), which resolves to OPENCODE_CONFIG_DIR when set. So the global instructions lookup skips ~/.config/opencode/AGENTS.md entirely.

The result: setting OPENCODE_CONFIG_DIR to add a secondary config directory (e.g. a workspace-level .opencode/) correctly picks up agents/commands/skills from both locations, but silently drops the global AGENTS.md unless you duplicate it into the override directory.

Steps to reproduce

1. Have a global AGENTS.md at ~/.config/opencode/AGENTS.md
2. Set OPENCODE_CONFIG_DIR to a different directory (e.g. /path/to/workspace/.opencode)
3. Start opencode
4. The global AGENTS.md is not loaded; only $OPENCODE_CONFIG_DIR/AGENTS.md is checked

Expected behavior

instruction.ts should use Global.Path.config (the static XDG path) for the global AGENTS.md, consistent with how ConfigPaths.directories() handles config directory scanning. OPENCODE_CONFIG_DIR should add to the search path, not replace the global instructions source.

Relevant code

• packages/core/src/global.ts:63 -- config: Flag.OPENCODE_CONFIG_DIR ?? Path.config
• packages/opencode/src/session/instruction.ts:64 -- path.join(global.config, "AGENTS.md")
• packages/opencode/src/config/paths.ts:26 -- Global.Path.config (static, not overridden)

Version

opencode 1.15.6, Linux