Codex CLI

Auto-wired

Sigil connects to Codex CLI (OpenAI’s coding agent) via MCP and an AGENTS.md steering file. After sigil init, Codex has access to the shared memory brain.

What you get

9 Sigil MCP tools available in Codex CLI sessions
An AGENTS.md entry in ~/.codex/ that steers Codex to query memory
The same shared brain as Claude Code, Cursor, and Kiro

Setup

sigil init

Sigil writes to:

~/.codex/config.toml — MCP server entry
~/.codex/AGENTS.md — steering instruction

No manual steps needed.

Manual setup

sigil register --print

Add the MCP entry to ~/.codex/config.toml in TOML format:

[mcp_servers.sigil]
command = "/usr/local/bin/node"
args = ["/path/to/sigil/dist/server.js", "--mcp"]
env = { DOTENV_CONFIG_PATH = "/Users/you/.sigil/.env" }

And add to ~/.codex/AGENTS.md:

Before answering questions about this project's architecture, decisions, or preferences,
call the Sigil `search` MCP tool. When the user shares a preference, decision, or
constraint worth keeping, call `ingest` to save it.

Using Sigil from the Codex CLI directly

Codex CLI also supports shell tool calls. You can use the Sigil CLI directly if Codex has shell access:

sigil search "what's our database setup"
sigil remember "Codex discovered that queue processing uses pg-boss"