Connect Vindex to Codex
Codex works through tasks in a repository. Connected to Vindex, it can read your rules and check what it writes against them before it hands the work back.
Three steps, about 3 minutes. Open to every registered Vindex user; new users create an account during sign-in, and a new account includes 100 free critique credits.
The walkthrough
Add the Vindex MCP server
From a terminal, register the server with the Codex CLI. This writes an entry to Codex's configuration, so the same server is available in the CLI and the IDE extension on this machine.
If you prefer editing the file, add a [mcp_servers.vindex] table to ~/.codex/config.toml with the url below. No key is stored in the file; sign-in happens in the next step.
codex mcp add vindex --url https://mcp.vindexgateway.com/mcpSign in with your Vindex account
Run the login command for the server. Codex opens your browser on the Vindex sign-in; use the account you use for the Vindex Portal, or create one to start on the free plan.
When the browser confirms the sign-in, Codex records the session. Running codex mcp list shows vindex as authenticated.
codex mcp login vindexRun your first critique
Ask your agent to list your rules, then to check a draft against one. Reading your rules is free, and each critique uses one critique credit.
The result comes back in the chat: pass or fail for each rule, with the failing passage quoted.
List my Vindex rules.Check this draft with Vindex against the "Email tone" rule: <paste the draft>What comes back
Each rule gets a pass or fail, and a failure quotes the passage that broke the rule. A rule set also returns one overall result and the names of the rules that failed. The result carries the attempt number and your credits left.
Codex does not block anything on its own. It gets the result and decides what to do next: usually, rewrite the quoted passage and run the critique again. Critique results and the loop has every field.
Tell the agent to run the loop
Codex reads AGENTS.md from the repository root (and parent directories) at the start of a task. Put the standing instruction there.
Before you send or save any customer-facing text, check it with the
Vindex validate tool against the rule set named below.
Rule set: <your rule set or rule name>
If a rule fails, rewrite only the passage the result quotes, then run
validate again. Stop when every rule passes, when the attempt limit is
reached, or when credits run out. Then tell the user which rule, if any,
is still failing. Never describe an output as checked unless validate
returned a result for it.An agent that follows it runs the loop on its own, and the server refuses a call over the attempt limit. The standing instructions guide has more.
Troubleshooting
codex mcp login vindex does not open a browser
Copy the URL Codex prints into a browser by hand, complete the sign-in, and return to the terminal. On a remote machine, run the login step locally and let Codex sync the configuration.
The agent answered without running a critique
Ask for it in the request: say "check it with Vindex". Put the standing instruction in your client's instructions file so it applies on every task. An agent chooses whether to call a tool, so treat an output as checked only when a result came back.
A critique came back as one sentence with no pass or fail
That sentence is a refusal or an error, such as no credits left, a rule that is not active, or a timeout. Ask your agent to check your credit balance, or try again in a moment.
Using a different client?
Scoring user stories too?
The same connection and the same sign-in also score a story against INVEST. That is part of Integrated Vindex.
Stories in your AI client