Connect Codex to Your Social Accounts Over MCP

I already wired Claude Code into PostSider over MCP and wrote up the setup. This is the Codex version. The server is the same; the client config is not. By the end, Codex will be able to list the channels already connected in PostSider and create a draft through the MCP tools.

If you already read the Claude Code guide, skip to the differences section. If this is your first MCP setup, keep reading top to bottom.

Codex needs one PostSider connection, not a platform integration

The mistake people make picturing “Codex posts to social media” is imagining OAuth apps for X, LinkedIn, and every other network Codex would need to touch. PostSider already holds those connections behind its dashboard. Codex only needs to speak to PostSider, and PostSider handles the provider-specific side.

@postsider/mcp wraps the PostSider public API as MCP tools. Point Codex at that package, give it your PostSider API key, and it can work with the channels already connected to your account.

Setup: one API key, one CLI command

You need two things: a PostSider API key and one MCP server entry in Codex.

Get the key first. In the PostSider dashboard, open Settings, then Developers, then Public API, and generate a key. That value becomes POSTSIDER_API_KEY. Treat it like a password. An optional POSTSIDER_API_URL variable exists for a non-default API host; if you omit it, the client uses the normal PostSider API host.

Register the local stdio server with Codex:

codex mcp add postsider --env POSTSIDER_API_KEY=your-api-key -- npx -y @postsider/mcp

The command names the server postsider, sets the environment variable for the subprocess, and tells Codex to start npx -y @postsider/mcp over stdio.

Check the registration:

codex mcp list

Current Codex also supports editing MCP configuration directly. The normal user-level file is ~/.codex/config.toml, and trusted projects can use a project-scoped .codex/config.toml when you want the MCP setup tied to one repository instead of every Codex session on the machine.

A user-level local server entry looks like this:

[mcp_servers.postsider]
command = "npx"
args = ["-y", "@postsider/mcp"]

[mcp_servers.postsider.env]
POSTSIDER_API_KEY = "your-api-key"

If you store credentials in config files, keep those files private and out of version control. For a shared project config, do not commit a real API key.

First test: ask Codex what channels are connected

Do not start by asking it to publish. Start with a read-only request: “what social channels do I have connected in PostSider?”

If Codex can answer with the real channels from your account, three things are working at once: the MCP server launched, the API key was passed correctly, and PostSider accepted the request.

Only then move on to a draft. For example: “find a free slot on LinkedIn this week and draft a post about the release we just shipped. Do not publish it.”

That keeps the first real write operation reviewable. The result should appear in the PostSider calendar like a draft created from the dashboard.

Keep drafts as the default until the workflow earns more trust

An agent that can publish immediately can also publish something wrong immediately. For the first few days, keep the workflow draft-first. Let Codex write, select a channel and prepare the post, then make the final publish decision in PostSider.

That gives you the useful part of the automation without turning a bad prompt, wrong channel choice or malformed post into a public mistake.

The PostSider calendar remains the operational view. If an agent creates something you did not expect, you can inspect the resulting post in the same place as manually created content instead of treating the agent as a separate publishing system.

Where Codex and Claude Code differ now

The PostSider MCP server does not change between clients. The difference is how each client stores and manages MCP configuration.

	Claude Code	Codex CLI
Add command	claude mcp add ...	codex mcp add ...
Project-shared config	.mcp.json	.codex/config.toml in trusted projects
User config	Claude user/local MCP config	~/.codex/config.toml
Local PostSider transport	stdio	stdio
Verify connection	/mcp or claude mcp list	codex mcp list

Codex also supports remote HTTP MCP servers. PostSider’s npm package is a local stdio server, so the command above is the relevant setup for this integration.

The two minute version

Generate a PostSider API key, run:

codex mcp add postsider --env POSTSIDER_API_KEY=your-api-key -- npx -y @postsider/mcp

Then run codex mcp list, ask Codex to list your connected PostSider channels, and only after that ask it to create a draft. Keep the draft in the calendar until you have reviewed it.

If you have not connected your accounts yet, start at app.postsider.com/register. For the current PostSider API and MCP details, use docs.postsider.com. If you want the Claude Code version of the same setup, see Give Claude Code a Social Media Presence.