# Observe and enforce

> Run an agent in observe to see what Thoth would decide, then enforce when you're ready.

Source: https://docs.atensecurity.com/docs/operations/enforcement-modes

Each agent runs in one of two modes:

- **Observe**: Thoth evaluates every action exactly as it would when enforcing, records the
  decision it would have made, and lets the action run. Nothing is denied or held.
- **Enforce**: decisions apply. Denied actions don't run, held actions wait for a person to
  approve them, and allowed actions run.

An agent with no mode set enforces: every default policy and profile does.

## Decisions

Thoth's decisions are the five of the AARM specification:

| Decision | While enforcing |
| --- | --- |
| `ALLOW` | The action runs as requested. |
| `DENY` | The action does not run. Older APIs and SDKs call this `BLOCK`; both names are accepted. |
| `STEP_UP` | The action waits for a person to approve it. If nobody does before the hold expires, it is denied. |
| `MODIFY` | A changed version of the action runs, for example with a credential removed. |
| `DEFER` | The action waits for more context. The built-in profiles don't produce it yet. |

In observe, each of these is recorded as what enforcing *would have* done, and the action runs.

## What enforcing would change

For an agent in observe, the observe summary counts what enforcing would have denied, held,
modified or deferred over the last 7 days (up to 30), with the rules that matched most and recent
examples you can open in Activity.

```bash
thothctl agents observe-summary --agent-id billing-agent
```

```http
GET /{tenant}/thoth/v1/agents/{agent_id}/observe-summary?days=7
```

## Changing the mode

Changing an agent's mode needs an admin with a recent second factor. A signed-in `thothctl`
session confirms it in the browser; an API key used by Terraform does not need to.

```bash
thothctl agents mode set --agent-id billing-agent --mode observe
thothctl agents mode set --agent-id billing-agent --mode enforce
thothctl agents mode get --agent-id billing-agent
```

```terraform
resource "thoth_agent_enforcement" "billing" {
  agent_id         = "billing-agent"
  enforcement_mode = "observe" # observe | enforce
}
```

Destroying the Terraform resource returns the agent to enforce. In Pulumi the resource is
`thoth.governance.AgentEnforcement`. The `thothctl` commands need thothctl 0.3.12 or later, and the
Terraform resource provider 0.1.22 or later.

From an MCP client connected to the [configuration server](https://docs.atensecurity.com/docs/mcp/configure-thoth), ask for
`preview_enforcement_mode`. The preview states what changes for the agent; committing it while
signed in returns an approval link you confirm in the browser with MFA. The agent must be
registered first.

### When a risk score is high

Rules decide every action. Where a model risk score is available, it can only make a decision
stricter, never allow something the rules would not. While enforcing, `high_risk_action` says what
a high score does: `hold` the action for approval (the default) or `deny` it.

### Older mode names

Earlier versions used other names. They are still accepted and stored as the two modes:
`monitor` and `shadow` are observe; `review`, `step_up` and `progressive` are enforce; `block` is
enforce with `high_risk_action = deny`.