---
id: USER-WP-0004
type: workplan
title: "User Engine Multi-Application And Catalog Support"
domain: netkingdom
repo: user-engine
status: ready
owner: codex
topic_slug: netkingdom
planning_priority: high
planning_order: 4
created: "2026-05-22"
updated: "2026-05-22"
depends_on:
  - USER-WP-0002
state_hub_workstream_id: "85676f7f-c82c-411a-9e1f-92098e8662ba"
---

# USER-WP-0004 - User Engine Multi-Application And Catalog Support

## Goal

Support multiple registered applications, catalog namespace ownership,
versioned customization catalogs, application-specific profile layers, and
runtime projections without attribute collisions or data leakage.

## Tasks

```task
id: USER-WP-0004-T1
status: todo
priority: high
state_hub_task_id: "a9952b07-35e0-4b6a-921e-321c55fee011"
```

Implement user-engine application records with bindings to external client,
protected-system, catalog namespace, event identity, and deployment metadata.

```task
id: USER-WP-0004-T2
status: todo
priority: high
state_hub_task_id: "d4ada2e3-9859-489c-b2a9-529b0d9e03fb"
```

Implement catalog namespace ownership, semantic versions, lifecycle states,
compatibility checks, and sensitivity downgrade prevention.

```task
id: USER-WP-0004-T3
status: todo
priority: high
state_hub_task_id: "add3cbdb-f7ec-4362-a257-93ab874a2093"
```

Add application-specific profile values, preferences, defaults, and precedence
rules.

```task
id: USER-WP-0004-T4
status: todo
priority: high
state_hub_task_id: "d5ef60ee-c007-4efd-86e4-3244e92c555a"
```

Implement application runtime projections with attribute-level visibility,
mutability, sensitivity, and redaction rules.

```task
id: USER-WP-0004-T5
status: todo
priority: medium
state_hub_task_id: "c824c44d-24f5-4f28-91fd-4d739b5fa254"
```

Specify and optionally prototype a cache-backed claims-enrichment projection
adapter that does not make user-engine a token issuer.

```task
id: USER-WP-0004-T6
status: todo
priority: high
state_hub_task_id: "8a506280-d8d6-4fbd-9d05-831a76e3e8be"
```

Add tests for namespace collisions, catalog activation failures,
application-specific profile values, projection redaction, application access
denial, and catalog migration checks.

```task
id: USER-WP-0004-T7
status: todo
priority: medium
state_hub_task_id: "c8fd8760-ccc4-4df4-85c7-c1c4950b82d9"
```

Add developer-facing examples for registering an application, publishing a
catalog, requesting projections, and handling profile-change events.

## Acceptance Criteria

- Multiple applications can register without attribute collisions.
- Catalog ownership and lifecycle are enforced.
- Application-specific values resolve consistently with global and tenant
  layers.
- Claims enrichment remains optional and adapter-owned.