git:20260702.0c35e1f to git:20260702.0fd73be

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description: Set up and verify AgentGuards in Codex. Use when the user asks to configure AgentGuards, set their API key, or check that the guardrails are wired up correctly.

---

# AgentGuards setup

Guide the user through finishing AgentGuards setup after installing the plugin.

The plugin already bundles the MCP server and the enforcing hooks — the only

thing the user must supply is their API key.

## Steps

1. **Check for the API key.** Look for the `AGENTGUARDS_API_KEY` environment

variable. If it is missing or does not start with `ag_`, tell the user to:

- Get a key from the dashboard at https://agentguards.co/dashboard/keys

- Export it so both the MCP server and the hooks can read it. For the current

shell and future sessions, add to their shell profile

(`~/.bashrc`, `~/.zshrc`, etc.):

```

export AGENTGUARDS_API_KEY=ag_your_token_here

```

- Restart Codex (or start a new session) so the MCP server and hooks pick up

the key from the environment.

2. **Confirm the URL (optional).** AgentGuards defaults to

`https://prod.agentguards.co`. Only set `AGENTGUARDS_URL` if the user runs a

self-hosted instance.

3. **Fail-open vs fail-closed.** The hooks fail **closed** by default — if the

AgentGuards service is unreachable, actions are blocked. A user who prefers

availability over strict enforcement can set `AGENTGUARDS_FAIL_OPEN=true`.

Mention this only if they ask or report unexpected blocks.

4. **Verify.** Call the AgentGuards `health_check` tool from the `agentguards`

MCP server. Report whether the service is reachable and which key prefix is

active. If it fails, the most common cause is `AGENTGUARDS_API_KEY` not being

exported in the environment Codex was launched from.

5. **Summarize what is now active:** UserPromptSubmit input scanning, PreToolUse

shell-command authorization, PostToolUse web-content scanning, and the

`check_input` / `authorize_action` MCP tools.