Audit Trails for AI-Initiated Financial Actions

// Append-only audit log for every AI-initiated financial action
async function logAgentAction({ sessionId, modelVersion, trigger, toolName, params, response, humanApproved = null }) {
  // Write BEFORE executing the action — so even failures are logged
  var logEntry = {
    id: crypto.randomUUID(),
    ts: new Date().toISOString(),
    session_id: sessionId,
    model_version: modelVersion,     // e.g. "claude-opus-4-6"
    trigger,                          // the instruction or event that caused this action
    tool_name: toolName,              // e.g. "paystack_transfer"
    params: JSON.stringify(params),   // recipient, amount, reason — serialized
    response: null,                   // filled after execution
    human_approved: humanApproved,    // { by: "bonaventure@mctaba.com", ts: "..." } or null
    status: 'pending',
  };

  var entry = await db.aiAuditLog.insert(logEntry);

  return {
    logId: entry.id,
    // Call this after execution to record the outcome
    recordOutcome: async (apiResponse, status) => {
      await db.aiAuditLog.update(entry.id, {
        response: JSON.stringify(apiResponse),
        status, // 'success' | 'failed' | 'blocked'
      });
    },
  };
}

// Usage: log before transfer, record outcome after
async function agentTransfer({ sessionId, modelVersion, trigger, recipientCode, amount }) {
  var audit = await logAgentAction({
    sessionId, modelVersion, trigger,
    toolName: 'paystack_transfer',
    params: { recipientCode, amount },
  });

  try {
    var res = await fetch('https://api.paystack.co/transfer', {
      method: 'POST',
      headers: { Authorization: 'Bearer ' + process.env.PAYSTACK_SECRET_KEY },
      body: JSON.stringify({ source: 'balance', amount, recipient: recipientCode, reference: 'agent_' + audit.logId }),
    });
    var data = await res.json();
    await audit.recordOutcome(data, data.status ? 'success' : 'failed');
    return data;
  } catch (err) {
    await audit.recordOutcome({ error: err.message }, 'failed');
    throw err;
  }
}

• Supabase RLS — enable Row Level Security on the audit log table. Grant INSERT to the agent service role, deny UPDATE and DELETE to everyone including service_role. Verified by RLS policies, not application code.
• Append-only DB columns — use PostgreSQL triggers that raise exceptions on UPDATE/DELETE of the audit table:

CREATE OR REPLACE FUNCTION prevent_audit_modification()
RETURNS TRIGGER AS $$
BEGIN
  RAISE EXCEPTION 'AI audit log entries cannot be modified or deleted';
END;
$$ LANGUAGE plpgsql;

CREATE TRIGGER no_audit_update BEFORE UPDATE ON ai_audit_log FOR EACH ROW EXECUTE FUNCTION prevent_audit_modification();
CREATE TRIGGER no_audit_delete BEFORE DELETE ON ai_audit_log FOR EACH ROW EXECUTE FUNCTION prevent_audit_modification();

• Cloud storage — for long-term retention, export daily audit logs to S3 or GCS with Object Lock (WORM) enabled. Once written, the log file cannot be overwritten for the retention period.
• Hash chaining — each log entry stores the SHA-256 hash of the previous entry. Tampering with any entry breaks the chain and is detectable.

See agentic payout safety rails for what to prevent before an action reaches the audit log.

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