GitHub Copilot, Qwen Code and Mistral Vibe were listed in the ACP Registry under their registry ids (github-copilot-cli, qwen-code, mistral-vibe), so they showed as unrelated third-party agents and could not be installed over the built-in providers. Registry ids now map to the built-in ids: the rows use the built-in name and icon, install and update into <config>/agents/<id>.toml, show "x.y.z available" when the registry has a newer version, and fall back to the built-in command on PATH after Remove. Installing never overwrites a hand-written agent config, and Remove only deletes a registry install. Changing installed providers reloads them and drops stale probes, so New Task sees the installed version right away.
Co-authored-by: dengliu <5108773+dengliu@users.noreply.github.com>