> ## Documentation Index
> Fetch the complete documentation index at: https://docs.agentium.in/llms.txt
> Use this file to discover all available pages before exploring further.

# Compliance & Audit Trail

> Tamper-evident audit logging for EU AI Act compliance and enterprise governance

## Overview

The EU AI Act requires tamper-evident logging by August 2026. Agentium provides hash-chained audit logging, data retention management, GDPR right-to-erasure, and compliance reporting — all built on any `StorageDriver`.

## Quick Start

```typescript theme={null}
import { Agent, AuditLogger, openai } from "@agentium/core";
import { SqliteStorage } from "@agentium/core";

const storage = new SqliteStorage("audit.db");
const auditLogger = new AuditLogger(storage, {
  hashAlgorithm: "sha256",
});

const agent = new Agent({
  name: "compliant-agent",
  model: openai("gpt-4o"),
  compliance: {
    enabled: true,
    storage,
    retention: {
      defaultRetentionDays: 365,
      personalDataRetentionDays: 730,
    },
  },
});
```

## Hash-Chained Audit Log

Every audit entry includes a SHA-256 hash of `previousHash + content`, creating a tamper-evident chain:

```typescript theme={null}
const entry = await auditLogger.log({
  traceId: "run-123",
  agentName: "support-agent",
  action: "llm.call",
  input: "How do I reset my password?",
  output: "To reset your password...",
  metadata: { model: "gpt-4o", tokens: 150 },
});

// entry.hash — SHA-256 of (previousHash + content)
// entry.previousHash — links to previous entry
```

### Verify Chain Integrity

```typescript theme={null}
const result = await auditLogger.verify();
// { valid: true } or { valid: false, brokenAt: "entry-id" }
```

## Audit Actions

| Action          | Description                     |
| --------------- | ------------------------------- |
| `llm.call`      | LLM API call with input/output  |
| `tool.exec`     | Tool execution with args/result |
| `handoff`       | Agent-to-agent transfer         |
| `decision`      | Agent decision point            |
| `memory.access` | Memory read/write               |
| `output`        | Final response to user          |

## Querying the Audit Log

```typescript theme={null}
const entries = await auditLogger.query({
  agentName: "support-agent",
  userId: "user-123",
  fromDate: new Date("2025-01-01"),
  toDate: new Date("2025-12-31"),
  action: "llm.call",
});
```

## PII Scrubbing

Integrate with Agentium PII Guard to automatically scrub PII before logging:

```typescript theme={null}
import { PiiGuard } from "@agentium/core";

const auditLogger = new AuditLogger(storage, {
  piiScrubber: new PiiGuard({ mode: "redact" }),
});
```

## Events

| Event                         | Payload                                       |
| ----------------------------- | --------------------------------------------- |
| `compliance.audit.logged`     | `{ entryId, action, agentName }`              |
| `compliance.erasure`          | `{ userId, storesErased, entriesAnonymized }` |
| `compliance.retention.purged` | `{ purgedCount }`                             |