Codex
OpenAI coding agent CLI, configured through Home Manager and mise.
Managed by: nix/home/configs/codex/config.toml and nix/home/default.nix.
Main Settings
| Setting | Value |
|---|---|
| model | gpt-5.6-terra |
| model reasoning | high; plan mode uses xhigh |
| service tier | fast |
| approvals | on-request, reviewed by auto-review |
| sandbox | workspace-write, with network access |
| web search | live |
| file opener | VS Code |
| startup update check | disabled |
| default subagent | gpt-6-luna, xhigh reasoning |
Because web search is live by default, a codex exec run that must stay offline passes -c web_search="disabled" -c tools.web_search=false and shows a probe proving no web tool answered. The codex-subagent mod already writes both settings into its worker config.
The agents section caps depth at 2 and concurrent threads per session at 8. The TUI status line shows the current directory, Git branch, model reasoning, context use, and five-hour and weekly limits.
Agents and Hooks
Home Manager links the code-reviewer, oracle, and prose-editor agent definitions from nix/home/configs/codex/agents/.
Codex runs shared policy scripts through nix/home/configs/codex/hooks/claude-hook-adapter.py. nix/home/configs/codex/config.toml registers them for Bash and apply_patch calls, tool completion, prompt submission, and session stop.
The generated Codex agent instructions combine nix/home/configs/.agents/AGENTS.md, nix/home/configs/codex/AGENTS.md, and the shared nix/home/configs/.agents/output-manner.md. The skills declared in nix/home/default.nix are linked for both Codex and Claude Code.
Home Manager generates the writable Codex config from the repository file during activation and retains local project trust and MCP server entries outside this repository.