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Testing Your Approval Workflow

Verify your Preloop setup end-to-end: call a prelooped tool from your MCP client, receive the approval request, approve it, and confirm the tool executes and everything lands in the audit trail.

These tests use the hosted demo MCP server at https://example-mcp.preloop.ai/mcp, which provides harmless sample tools like pay and get_random_number.

Time Required: 10-15 minutes

Prerequisites:

Test 1: Basic Approval Workflow

Goal

Verify the complete approval flow works: call tool → receive notification → approve → tool executes.

Setup

Step 1: Add the Example MCP Server

If you haven't already:

  1. Go to Tools & MCP → + Add Source → MCP Server
  2. Configure: 
    Name: Example MCP Server
URL: https://example-mcp.preloop.ai/mcp
Transport: http-streaming
Auth Type: none
Status: active
  3. Click Save
  4. Click Scan Tools

Step 2: Preloop the pay Tool

  1. Find pay tool in Tools & MCP list
  2. Click Configure (gear icon)
  3. Toggle Require Approval to ON
  4. Set approvers: Add yourself
  5. Notification: Select "Email"
  6. Click Save

Execute Test

Step 1: Trigger Tool Call

In your MCP client (e.g., Claude Code):

Using @preloop tools, pay alice@example.com $500

Expected: the client sends the request and waits — the tool does NOT execute immediately.

Step 2: Check for Notification

Within 30 seconds:

  • Email: message from hello@preloop.ai, subject "Approval Required: pay", with the tool name, arguments, request ID, and Approve/Decline buttons
  • Web Dashboard: notification bell (top-right) shows a badge; click it to see the pending request
  • Mobile (if configured): push notification with tool name and key arguments

Step 3: Approve Request

Approve from any one channel:

  • Email: click Approve, confirmation page shows "Approval recorded successfully"
  • Web Dashboard: click the notification → review → Approve (optionally add a reason)
  • Mobile App: tap the notification → Approve → authenticate

Step 4: Verify Execution

In your MCP client the tool now executes and returns a result (illustrative):

Approval received
Payment of $500 sent to alice@example.com
Transaction ID: tx_abc123

In the dashboard, the request moves to "Approved" in Approvals → History.

Verify Audit Trail

  1. Go to Approvals → History
  2. Find your test request and click it
  3. Verify it shows: requester, tool (pay), arguments, status (Approved), approver, timestamps, and the execution result

Result

Pass if: notification arrives within ~30 seconds, approval works, tool executes only after approval, and the audit log shows the complete record.

Fail if: no notification, tool executes immediately without approval, or no audit log entry.

Test 2: Decline Workflow

Goal

Verify declining an approval request prevents execution.

Execute Test

Step 1: Trigger Another Tool Call

Using @preloop tools, pay bob@example.com $1000

Step 2: Decline Request

When the notification arrives, click Decline (email or dashboard) and add a reason, e.g. "Test decline".

Step 3: Verify No Execution

Your MCP client receives a decline message (illustrative):

Approval declined
Reason: Test decline
The tool was not executed.

The dashboard shows the request as "Declined" with your reason, and no execution result.

Result

Pass if: the tool does NOT execute, the client receives the decline message, and the audit log shows "Declined".

Fail if: the tool executes despite decline.

Test 3: Conditional Approval

Goal

Verify CEL conditions work: approval only required when the condition matches.

Setup

  1. Go to Tools & MCP → Find pay tool → Configure
  2. In Approval Condition, enter: 
    args.amount > 1000
  3. Click Save

This means: only require approval if amount > $1000.

Execute Test

Test A: Below Threshold

Using @preloop tools, pay charlie@example.com $500

Expected: no approval request — the tool executes immediately.

Test B: Above Threshold

Using @preloop tools, pay charlie@example.com $1500

Expected: approval request sent, client waits, tool executes after you approve.

Result

Pass if: small amounts execute immediately, large amounts require approval.

Fail if: all amounts require approval (condition ignored) or none do (condition broken).

Remaining Checks

Once tests 1-3 pass, the core Safety Layer works. Run through these quicker checks as needed:

  • Team-based approval with quorum (needs 2+ users): create a team under Settings → Teams, set it as the pay approver with quorum 2, and trigger a call. The tool must wait for the second approval before executing, and the audit log should show both approvers. See Team-Based Approvals.
  • Timeout and escalation: set a short timeout (e.g. 120s) and escalation delay (e.g. 60s) on the pay policy, trigger a call, and don't respond. The escalation contact should be notified after the delay, and after the timeout the client should receive a timeout error with the tool NOT executed.
  • Multiple notification channels: enable email, web, Slack, and mobile for the pay policy and trigger a call. All configured channels should notify within ~30 seconds, and approving from one channel should update the others.
  • Non-prelooped tool: call get_random_number from the example server with Require Approval OFF. It should execute immediately with no notification, but still appear in the audit trail.
  • Error handling: trigger a call with invalid arguments (e.g. pay invalid-email $-100) and approve it — the execution failure should be reported clearly. Then point the example server at an invalid URL and confirm you get a clean "server unavailable" error instead of a silent failure; restore the URL to https://example-mcp.preloop.ai/mcp afterwards.

Next Steps

Your setup is working. Next: Add your own MCP tools or create automated flows.