Summary

Introduce an official extension point in the Entity Overview tab to surface custom Error / Warning / Info messages from plugins (e.g. missing annotations, best-practice recommendations). These messages should be positionable near the top of the Overview tab, ideally aligned with or immediately after EntityOrphanWarning.

Problem

In RHDH there is no supported way for plugins to show validation messages
(Error / Warning / Info) in the Entity Overview tab.

• Teams either override OverviewTabContent (fragile), or

• create a new tab in the entity page, but users rarely visit custom tabs, so important messages are missed.

Current State / Gap

In vanilla Backstage, it is technically possible to inject custom frontend components into the Overview tab (including placing them before/after EntityOrphanWarning). However, in RHDH, there is currently no supported or stable mount point for plugins to contribute such validation messages.

Is it possible to support mounting custom error / warning / info components in the Entity Overview tab (e.g. near or after EntityOrphanWarning) without overriding the default behavior or existing components?

Something similar to what’s shown in the screenshot—allowing plugins to surface validation feedback while preserving the standard Overview layout.

Why This Is Needed

• Overview is where users expect health and status signals

• New tabs are often ignored, so messages may be missed

• Allows platform teams to deliver actionable feedback without custom pages or UI forks
• Unlocks reusable ecosystem plugins for policy, hygiene, and integration readiness

Proposal

Add a supported / Official mount point in the Entity Overview tab (near or after EntityOrphanWarning)
where plugins can render validation messages.

for example:

<EntityOverviewValidationMessages /> 

Requirements:

• Supports multiple contributors (from different plugins)

• Supports severity levels (Error / Warning / Info)

• Renders without replacing or reordering existing Overview content

• Preserves the standard RHDH look & feel

Typical Use Cases

• Missing required annotations

• Data freshness warnings (stale metadata, outdated sync)

• Deprecation notices (entity, API, or system deprecated)

• Breaking change warnings (schema, API, ownership change)

• Best-practice reminders (CI/CD, observability, ownership)

• Policy or compliance warnings

• Integration readiness checks

All of these are entity-level signals and naturally belong in the Overview tab.

Reference location in RHDH = https://github.com/redhat-developer/rhdh/blob/main/packages/app/src/components/catalog/EntityPage/OverviewTabContent.tsx#L37