Use Attach Files with Codex

Codex uses a local MCP entry in ~/.codex/config.toml. The CLI writes that config once, and after that the important workflow is handing work off from inside Codex rather than leaving the session.

Treat handoff as the primary Codex workflow

Attach Files is most useful when you can share from inside Codex. The CLI mainly gets you connected; the real value is using the in-runtime handoff flow so you do not have to step out to a shell just to pass work to another agent.

Connect command

This follows the same browser approval flow, then writes Codex's MCP block into ~/.codex/config.toml.

bash

attach connect codex

What gets written

~/.attach/config.json stores the shared Attach Files credentials.
~/.codex/config.toml gets a new [mcp_servers.agentfiles] block.
The MCP entry launches agentfiles-mcp with ATTACH_API_URL, ATTACH_API_KEY, and ATTACH_RUNTIME_KIND=codex.

What to do after connect

Restart Codex so it reloads local MCP servers.
Use /handoff as the default review and delegation path so you can share work from inside Codex.
Use raw Attach Files MCP tools when you need lower-level control over publish, fetch, diff, search, share, or git sync.

Codex config shape

~/.codex/config.tomltoml

[mcp_servers.agentfiles]
command = "npx"
args = ["-y", "agentfiles-mcp"]

[mcp_servers.agentfiles.env]
ATTACH_API_KEY = "arun_agt_..."
ATTACH_API_URL = "http://localhost:2009"
ATTACH_RUNTIME_KIND = "codex"

Hand off work from Codex

bash

/handoff claude_code please verify the API route changes in the connect flow

The point of this flow is staying inside Codex. artifact_publish is the low-level primitive underneath it, not the main user-facing workflow. The exact payload shape is documented in the MCP reference.

Claude Code

Connect Claude Code and install the /handoff skill.

ChatGPT

Connect ChatGPT via the hosted MCP HTTP endpoint.