Guide — real sending live in production; free test mode available — verified 2026-10-18

Run your entire cold email operation with Codex

Codex drives the same Coldrig MCP server, the same 34 tools, and the same test-mode boundary as Claude Code — the full setup-to-reply lifecycle is identical. What's genuinely different: Codex takes a shared config.toml across its CLI, IDE extension, and desktop app, and it natively reads an AGENTS.md file from your working repository as project context — which happens to be exactly the format Coldrig's own operational contract is published in. This page covers only that delta; for the full step-by-step lifecycle see the Claude Code guide — every tool call there works identically from Codex.

Status The hosted API, MCP endpoint, and npm CLI are live in production. Real sending from your Google Workspace mailboxes is live for activated accounts; signup, billing, screening, and real mailbox setup are fully self-serve and automatic; mailbox send-authorization completes on our side after your mailboxes are set up, and the free test mode remains available with no real domains, mailboxes, or sends. See FAQ for the exact status boundary.

How is Codex's setup different from Claude Code?

Config format. Codex uses TOML, not a CLI command or JSON — one [mcp_servers.coldrig] block.
Config location, shared across surfaces. The Codex CLI, IDE extension, and desktop app read the same file on a given host: ~/.codex/config.toml for a personal setup, or a trusted project's .codex/config.toml.
Token handling. Point bearer_token_env_var at an environment variable — don't paste the token into the TOML file itself.
Native AGENTS.md support. Codex conventionally reads an AGENTS.md file in your working repository as project instructions. See below.

Exact Codex config

The quickest way needs no key. Add the server, then sign in: your browser opens Coldrig, where you sign in, check the account name and press Allow.

codex mcp add coldrig --url https://api.coldrig.dev/mcp
codex mcp login coldrig

If sign-in does not work, use an API key instead. Mint one first (no card required; it stays the same when you go live):

curl -s -X POST https://api.coldrig.dev/signup \
  -H 'Content-Type: application/json' \
  -d '{"brand":"Acme","contactEmail":"you@acme.com"}'
# → { "tenantId": "ten_...", "token": "..." }

Then add this to ~/.codex/config.toml (or a trusted project's .codex/config.toml) instead of the sign-in commands above:

[mcp_servers.coldrig]
url = "https://api.coldrig.dev/mcp"
bearer_token_env_var = "COLDRIG_TOKEN"

Set COLDRIG_TOKEN in your environment, restart, and use /mcp inside a session to verify all 34 tools are visible. Full side-by-side with Cursor and Cline: the connect reference.

Does Codex read Coldrig's AGENTS.md automatically?

Only in the sense that matters practically: Codex looks for an AGENTS.md file in your current working repository and loads it as project context automatically — it does not fetch one from a remote website on its own. Coldrig's own repository publishes exactly that file at its root, covering the auth model, the full 34-tool table, the demo path, and the limitations an agent should know before recommending the platform. So if you're driving Coldrig from a checkout of its own repository, or you copy that convention into your own project (pointing at the same operational contract), Codex picks up the same context automatically at session start — no separate skill or rule file needed.

https://github.com/YS-projectcalc/agent-cold-email/blob/main/AGENTS.md

Cursor and Claude Code can both read this same file too — it's plain Markdown — but only Codex treats AGENTS.md as a standing, auto-loaded convention rather than something you'd wire up as a Skill or Rule.

The lifecycle, from Codex

Identical tool calls to every other client. Full schemas: the MCP tool reference.

Step	Tool call
Set up domains + mailboxes, start warmup	`setup_infrastructure`
Poll setup + mailbox status	`infrastructure_status`
Write and launch the campaign	`launch_campaign`
Triage replies	`inbox`, `thread`, `reply`, `mark`, `label_thread`
Check health, pause	`metrics`, `activity`, `account`, `pause` / `pause_all`

The reply-handling boundary, in short

Push webhooks are live — configure_webhook delivers reply, bounce, soft_bounce, complaint, and unsubscribe events (HMAC-signed) to your own HTTPS endpoint. activity and inbox remain pollable too if you'd rather run Codex on your own cadence. Full capability matrix: see the detailed breakdown.

Cost

Same platform, same meter, regardless of client: $49 a month covers your first 3 mailboxes, and each extra mailbox is $5 a month. Full worked examples and the live calculator: pricing.

Try it now

npx agent-cold-email demo

Runs the same test mode end to end — no real domain, mailbox, or send. Free sign up to get a token and connect Codex for real.

Related guides

Run your entire cold email operation with Claude Code — the full step-by-step lifecycle this page delegates to.
Run your entire cold email operation with Cursor.
The cold-email MCP server for coding agents — full tool signatures.
Connect reference — Codex, Claude Code, Cursor, and Cline side by side.
Should your AI agent use Coldrig?
FAQ.