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How to Debug a NinjaTrader Trade Copier with AI

The CrossTrade trade copier moves orders from a leader to one or more followers. When a follower misses, the broker UI usually shows nothing. The CrossTrade Add-On activity log holds the truth. With CrossTrade MCP, an AI agent reads both leader and follower logs in one conversation and points at the gap.

Direct answer​

Authenticate with mcp:read. Run this prompt with the leader, follower, and time window:

For leader <leader_account> and follower <follower_account> between <start> and
<end>:
1. GetActivityLog for both accounts.
2. ListOrders and ListExecutions for both in the same window.
3. ListPositions for both.
4. Build a single chronological timeline.
5. Identify the step where the follower path broke.
6. State the verbatim rejection reason if any.
7. Suggest a one-line preventive check.
Do not place, cancel, modify, or flatten anything.

The agent reconstructs the timeline. The rejection reason is usually one line, like "follower rejected: max contracts (existing 4 + routed 2 > limit 5)".

Common copier failures​

PatternCause
Leader filled, follower rejectedMax contracts on follower account
Follower late or out of syncRouting delay or follower broker latency
Wrong quantity on followerCopier ratio or per-account override
Follower took the wrong sideConfiguration error in copier mapping
Two accounts diverged silently over timeManual trades on one account, or copier-disabled window

Prerequisites​

RequirementDetail
CrossTrade subscriptionElite
CrossTrade Add-Onv1.13.0 or higher
MCP clientAny
Scopemcp:read

Step 1: Confirm the symptom​

Before running the agent, note the leader fill time and the follower account that missed. A 5-minute window around the leader fill is usually enough.

Step 2: Run the diagnostic prompt​

Paste the prompt above with your specific accounts and window.

Step 3: Read the timeline​

Look for the step where the follower path stops. Typical patterns:

14:32:09.812  LEADER  order placed
14:32:10.041  LEADER  fill confirmed
14:32:10.044  copier  leader fill received
14:32:10.047  copier  follower routing started
14:32:10.121  copier  follower rejected: max contracts (existing 4 + routed 2 > limit 5)
14:32:10.121  FOLLOWER  no order placed

The verbatim rejection reason is what you want. It usually tells you exactly which check fired.

Step 4: Fix the underlying issue​

CauseFix
Max contracts on followerReduce existing position or raise the per-account limit (if firm rules allow)
Follower disconnectedReconnect the follower account in NT8
Symbol mappingConfirm both accounts subscribe to the same instrument; update copier mapping
Existing position conflictFlatten the conflicting position manually
Copier ratio mismatchUpdate copier configuration in CrossTrade
Bracket/ATM mismatchMake sure both accounts have compatible bracket settings

Step 5: Verify with a test signal​

After the fix, fire a controlled leader order on Sim101 (or whatever non-funded environment you use for tests) and re-run the diagnostic prompt. The agent should report the follower path matched.

Funded futures considerations​

  • Apex prohibits automation entirely; a copier that routes to an Apex follower may violate firm rules even when CrossTrade can technically perform the route. Verify the firm's automation policy.
  • Some firms prohibit cross-firm copying. Verify before you rely on it.
  • Per-account max contracts on funded accounts usually cannot be raised without firm approval.