A skill is universal only when its instructions, references, tools, paths, and model guidance work unchanged in both Claude Code and Codex. Universal skills must not name a concrete provider model ID.
Use a native variant when a workflow depends on platform-specific dispatch, user-input, MCP, installation, or model-selection behavior. Claude and Codex variants keep the same behavioral contract but use their native vocabulary.
Shared references live in skills/_shared/ and are copied beside either
platform's skills. A skill name may exist in the universal tree or in both
platform trees, but never in universal and a platform tree at the same time.
Kiro agent definitions remain in each agents/<role>/ family. Kiro is not a
target of the Claude/Codex installer and does not change the universal versus
variant classification.
Claude agents use the Claude Code family aliases haiku, sonnet, and
opus, so the catalog does not freeze dated Claude model IDs. Haiku and
Sonnet and Opus use medium effort.
Codex Haiku and Sonnet use openai.gpt-5.6-luna at xhigh. Codex Opus uses
openai.gpt-6.1-sol at high. No Claude profile may use reasoning below
medium.
Claude Code resolves family aliases according to the provider and account
policy. Deployments that need explicit routing can set
ANTHROPIC_DEFAULT_HAIKU_MODEL, ANTHROPIC_DEFAULT_SONNET_MODEL, and
ANTHROPIC_DEFAULT_OPUS_MODEL outside this repository.