How to Connect Codex to dfin.pro MCP

Codex is OpenAI's AI assistant for research, analysis, and coding. Out of the box it works from its training data, but connecting it to dfin.pro gives it access to live financial information — company filings, earnings transcripts, financial statements, ratios, stock screens, and fund analytics — so you get answers grounded in actual data rather than an outdated snapshot.

There are three ways to make the connection, and you only need to follow one:

Section 2 — the Codex desktop app (recommended for most users)
Section 3 — the Codex CLI plugin (if you prefer working from the command line)
Section 4 — direct config.toml editing (a manual fallback if the above don't suit your setup)

All three paths require the API key step in Section 1, so start there regardless of which path you choose.

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1.0 Set the API key

Codex needs your dfin.pro API key stored as an environment variable named DFIN_API_KEY. An environment variable is a way to give an app a credential it can find automatically, without pasting it into a config file every time. Set it permanently using the commands below so Codex can still find it after you restart the app, open a new terminal, or start a new thread.

macOS Zsh

echo 'export DFIN_API_KEY="paste-your-api-key-here"' >> ~/.zshrc
source ~/.zshrc

Linux Bash

echo 'export DFIN_API_KEY="paste-your-api-key-here"' >> ~/.bashrc
source ~/.bashrc

Windows PowerShell

[Environment]::SetEnvironmentVariable("DFIN_API_KEY", "paste-your-api-key-here", "User")

Close and reopen PowerShell after setting the variable.

Windows Command Prompt

setx DFIN_API_KEY "paste-your-api-key-here"

Close and reopen Command Prompt after setting the variable.

2.0 Add the server in the app

If you're using the Codex desktop app, this is the quickest path. First, make sure you have the latest version installed from the official OpenAI website.

2.1 Configure the MCP

Click the settings gear at the bottom left, then click Settings in the menu. In the left menu, find MCP servers under Integrations. Click Add Server.

Codex app MCP settings showing the Add Server button

In the next window, select Streamable HTTP and fill in the three fields:

MCP server name: dfin
URL: https://www.dfin.pro/mcp
Bearer token env var: DFIN_API_KEY

Click Save.

Codex app custom MCP server form configured for dfin.pro

If the UI does not expose the bearer-token environment variable option, use the config.toml setup instead.

Once the server is saved, ensure it's enabled.

Codex app MCP servers list showing the dfin server enabled

Once saved, open a new Codex chat to activate the connection, then use the checks in Section 5 to confirm it's working.

2.2 Optional: add the skill

Installing the dfin.pro skill gives Codex better default behavior for financial research — it knows how to phrase queries, which tools to reach for, and how to structure the results. It's not required, but it makes a noticeable difference if you plan to use dfin.pro regularly.

The skill is published on GitHub at dfin-pro/dfin-financial-mcp.

You can install it with /skill-installer.

Codex confirming that the dfin MCP server is available

Click the option that appears, then paste the GitHub repository link.

Codex skill installer prompt for the dfin.pro GitHub repository

Once it is installed, Codex will confirm the installation and ask you to restart. Use the platform-specific restart steps at the end of this guide so the app fully reloads.

Codex confirming that the dfin.pro skill was installed

3.0 Install the CLI plugin

This section is for Codex CLI users. If you set up the connection through the desktop app in Section 2, you can skip this.

The dfin.pro Codex plugin is published from the GitHub-backed marketplace source at dfin-pro/dfin-financial-mcp. Add that marketplace source first:

codex plugin marketplace add dfin-pro/dfin-financial-mcp

Then install the plugin from Codex.

In the Codex app, open Plugins, choose the dfin.pro marketplace source, and install dfin-financial-mcp.

In Codex CLI, run:

codex
/plugins

Choose the dfin.pro marketplace source, open dfin-financial-mcp, and select Install plugin.

Start a new Codex thread after installation. The plugin bundles the MCP connection config for https://www.dfin.pro/mcp and the dfin-research skill, so you don't need to paste the MCP server settings by hand.

4.0 Edit config.toml

Codex stores MCP configuration in config.toml. On Windows, the file is typically under C:\Users\<your-user>\.codex\config.toml.

Add this server entry to your Codex config:

[mcp_servers.dfin]
enabled = true
url = "https://www.dfin.pro/mcp"
bearer_token_env_var = "DFIN_API_KEY"

For most local installs, the config file is ~/.codex/config.toml. If you keep project-scoped Codex settings, use the trusted project's .codex/config.toml instead.

5.0 Check that it works

Restart Codex after changing environment variables, installing the plugin, or editing config.toml.

On Windows, fully quit the Codex desktop app from the taskbar or system tray by right-clicking Codex and choosing Exit, then reopen it.

On macOS, fully quit Codex with Codex > Quit Codex, Command+Q, or the Dock quit action, then reopen it.

For Codex CLI, use /exit or /quit. If you added DFIN_API_KEY after the terminal was already open, close and reopen the terminal before running codex again.

In a new Codex thread, open:

/mcp

Confirm that the dfin server appears connected. Then ask a small question that should use dfin.pro, such as:

Give me an overview of Micron's revenue and margins over the last 5 years.

Here's what that looks like:

Codex using dfin.pro MCP to answer a Micron stock context question

If the server does not appear connected, check that DFIN_API_KEY is set in the same environment Codex is running in and that the server URL is exactly https://www.dfin.pro/mcp. If you're still stuck, reach out at [email protected].