# `aristo install-skills --agent=codex` — AGENTS.md section injection

Source: `../aretta-sdk/docs/mockups/12-phase-1-architecture/cli-sessions.md` § "K4 → Agent 3: Codex (AGENTS.md section-injection model)".

The AGENTS.md install model (per K4): instead of writing per-skill files, inject a single marker-delimited block into the project's `AGENTS.md`. Hand-written content outside the markers is preserved across reinstalls / updates.

Block format: `<!-- ARISTO-SKILLS START vX.Y.Z -->` … `<!-- ARISTO-SKILLS END -->`. The version pin in the start marker lets `--update` detect drift and rewrite the block in place.

```console
$ aristo install-skills --agent=codex

→ Installing Aristo skills for Codex …
  • AGENTS.md found at [..]/AGENTS.md
  • Existing content preserved; injecting marker-delimited Aristo section

  Injected block (lines [..] of AGENTS.md):
  ┌───────────────────────────────────────────────────────────────
  │ <!-- ARISTO-SKILLS START v[..] -->
  │ # Aristo annotation skills (auto-generated by `aristo install-skills`)
  │
  │ ## aristo-authoring
  │ You are helping the developer author Aristo annotations.
  │ Before generating annotations, run `aristo lang` …
  │ [content from skills/_content/aristo-authoring.md]
  │
  │ ## aristo-neural-verify
  │ [content from skills/_content/aristo-neural-verify.md]
  │
  │ ## aristo-mine-assertions
  │ [content from skills/_content/aristo-mine-assertions.md]
  │
  │ ## aristo-review-skill
  │ [content from skills/_content/aristo-review-skill.md]
  │ <!-- ARISTO-SKILLS END -->
  └───────────────────────────────────────────────────────────────

ok: 4 skills installed for codex.

Note: future `aristo install-skills --agent=codex --update` rewrites ONLY
the marker-delimited block — your hand-written AGENTS.md content is preserved.

```
