How to post to a Facebook Page from OpenAI Codex

Set it up and post, step by step

Prompt to copy once your Page is connected: Read CHANGELOG.md, write a Facebook post for the v3.1 release in plain words for our customers, show it to me, and schedule it for Thursday at 10am with ./assets/v3.1.png.

1. Add PostWire to Codex

   In your terminal run codex mcp add postwire --url https://postwire.io/api/mcp, then codex mcp login postwire. The browser opens PostWire's sign-in, which asks for your email and a 6-digit code and also creates a free PostWire account if you have none: no password and no card. codex mcp list, or /mcp inside Codex, shows postwire with its tools. In the IDE extension, the gear menu's MCP servers lists the same entry.

2. On a server without a browser, sign in another way

   codex mcp login postwire --no-browser gives you a sign-in link to open on any device. In CI, give Codex your key instead: copy it in the dashboard under API & MCP, set POSTWIRE_API_KEY, and put the variable's name in ~/.codex/config.toml, never the key itself:

   [mcp_servers.postwire]
   url = "https://postwire.io/api/mcp"
   bearer_token_env_var = "POSTWIRE_API_KEY"

3. Connect your Facebook Page

   Ask "connect my Facebook Page". Codex calls create_connect_link and prints a one-hour link; open it and choose Facebook. Facebook shows "Continue as <your name>", then asks which Pages PostWire may use: tick the Page and press Save. Pages you manage directly and Pages inside a Business Portfolio both appear. PostWire never sees your Facebook password.

4. Ask for the post

   "Write the Facebook post for the release." generate_posts returns a draft and publishes nothing. It is written for Facebook: 40 to 80 characters when the idea allows and under 250 otherwise, the hook in the first 125 characters (where the mobile feed cuts), 1 to 3 hashtags, and a link can stay in the body. Ask for the LinkedIn or Instagram version in the same sentence and each comes back written for its own network.

5. Attach a photo or a video, if you want one

   Facebook fetches media from a link, so a file on your disk goes through an upload page: Codex asks for one (create_upload_link, valid 24 hours, up to 100 MB on the free plan and 1 GB on paid plans), you pick the file there, and get_uploaded_file hands Codex its link. A file that is already online goes as its public https link in photo_url or video_url.

6. Post now, or schedule it

   Say "post it" and Codex calls post_to_social. Say "schedule it for Thursday at 10am" and it calls schedule_post, up to 365 days ahead, or with run_at: "next_slot" for your next free posting hour. This is the call:

   {
     "name": "schedule_post",
     "arguments": {
       "platforms": ["facebook"],
       "per_platform": { "facebook": {
         "text": "v3.1 is out: invoices export to CSV, and search is twice as fast. What should we fix next? #productupdate"
       } },
       "photo_url": "https://postwire.io/m/…/v3.1.png",
       "run_at": "2026-11-12T10:00:00-05:00"
     }
   }

7. Check that it went out

   The result lists Facebook with ok, the Page it went to and the post's link (https://facebook.com/…). If Facebook refuses it, the result says what happened and how to fix it. "What's scheduled on Facebook?" calls list_scheduled_posts and "cancel Thursday's post" calls cancel_scheduled_post.

Reels and Stories go through the REST API today, which Codex can call from the terminal with your key: POST /api/post with "options": {"facebook": {"post_type": "reel"}} or "story". Prefer to set it up by hand? Open the dashboard, connect your Page under Accounts and copy your key under API & MCP.