Adobe Target MCP: update_activity with secondary metrics converts VEC activities to form-based, then blocks further updates

Hi not sure this is the right place for it but the Target MCP has a bug that flips VEC tests to Form tests when adding secondary goals. Below is summary of issue from Claude. 

Environment

• Connector: Adobe Target MCP (https://targetmcp.adobe.io/mcp), used from Claude
• Activity type: A/B (manual), created in the Visual Experience Composer, server-side decisioning
• Date observed: 14 October 2026

Issue 1: adding secondary metrics flips a VEC activity to form-based

Steps to reproduce:

1. Create a VEC A/B activity, through the UI or create_vec_activity. get_activity returns experienceEditorType: "visual".
2. Call update_activity with a metrics array containing the primary metric (metricLocalId: xx, conversion: true) and one additional metric (metricLocalId: xxx, conversion: false, mbox success event).
3. The tool’s response shows experienceEditorType: "visual".
4. Call get_activity again about 1 second later.

Expected: the activity remains visual and opens in the VEC.

Actual: modifiedAt advances by about 1 s with no further user action, and three things change:

• experienceEditorType is now "non_visual".
• primaryMetricType: "conversion" has been added.
• successCriteria has been auto-expanded to include every metric.

The activity then opens in the Form-Based Composer in the Target UI, with no locations shown.

Isolation: on a throwaway activity, the following each left the activity visual. Only step 2 above caused the flip.

• update_activity_name
• update_activity_priority
• update_activity_schedule
• update_activity_state
• update_traffic_split
• update_variant_offer
• update_activity with only reportingAudiences
• update_activity with only the primary metric
• update_activity with only successCriteria

Secondary metrics added through the Target UI do not cause the flip. A live activity has 10 UI-added secondary metrics and remains visual.

Issue 2: flipped activities can no longer be updated via update_activity

After the flip, every update_activity call fails, whatever the payload, including a reporting-audiences-only change:

Target API error: Invalid Json. Unrecognized property name 'experienceLocalIdCounter'.
status=400 | PUT https://mc.adobe.io/azeu/target/activities/ab/{id}

The tool appears to route non_visual activities to the Admin API endpoint while its read-merge-write payload still contains UI-endpoint-only fields (experienceLocalIdCounter and similar). Before the flip, the same tool wrote successfully via /target/ui/activities/ab/{id}.

Related observation

On two activities whose page-delivery audience was an inline (anonymous) audience, a manual save in the Target UI after the flip removed the page-delivery audience from the location. The audiences themselves were deleted, and get_target_audience now returns 404. Had they been activated, they would have delivered site-wide.

Impact

• Configuring standard goals through the MCP silently converts VEC tests to form-based.
• Those tests are then locked out of further MCP edits.
• Fixing them in the UI can strip page targeting.

Our workaround is to add secondary metrics only in the UI.

Requests

1. Prevent update_activity metric writes from changing the editor type of VEC activities.
2. Strip UI-only fields when update_activity routes to the Admin API, so flipped activities can still be updated.