# Compatibility Matrix

Agent Spine is Codex-native at the core and adapter-friendly at the edges.

| Surface | Status | Purpose | Source Of Truth |
| --- | --- | --- | --- |
| `AGENTS.md` | canonical | repo-wide operating contract | yes |
| `.codex/` | canonical | Codex config, hooks, policy, subagents | yes |
| `.agents/skills/` | canonical | reusable shared-brain workflows | yes |
| `.claude/` | optional adapter | Claude Code settings, hooks, and role mirrors | no |
| `CLAUDE.md` | optional adapter shim | short Claude entry point that defers to `AGENTS.md` | no |
| project CI | external but required | runtime lint, test, build, release gates | project-owned |
| generic prompt docs | supporting | explanatory guidance only | no |

## Rule

If a rule should affect every agent, put it in the canonical contract first. Mirror it into adapters only when a tool needs a tool-specific format.

## Claude Code

Claude Code compatibility is valuable for discovery and mixed-agent teams. It should remain visible in README, Pages, and docs, while `.claude/` stays removable without breaking the core template.