Draft capability entry (reuse-surface REUSE-WP-0017-T04, cohort 3)

Honest first-pass maturity vector grounded in README/docs/tests present
in this repo; no invented evidence. Flagged for human review before
publish. See reuse-surface history/2026-07-06-coverage-classification.md.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

registry/capabilities/capability.identity.user-engine.md

@@ -0,0 +1,123 @@
+---
+id: capability.identity.user-engine
+name: Headless Multi-Tenant User Engine
+summary: Headless, multi-application, multi-tenant user management engine covering registration, identity/factor
+  models, entitlement claims, hats/realms/services/assets access profiles, and onboarding journeys.
+owner: user-engine
+status: draft
+domain: communication
+tags:
+- identity
+- user-management
+- multi-tenant
+maturity:
+  discovery:
+    current: D4
+    target: D5
+    confidence: high
+    rationale: 'Unusually large documentation set for its size: docs/development.md, configuration.md,
+      contracts.md, canon-mapping.md, canon-interface-card.yaml, family-dataspace-onboarding.md, registration-identity-and-factor-model.md,
+      prepared-accounts-and-entitlement-claims.md, hats-realms-services-assets-access-profiles.md, onboarding-journeys-and-welcome-protocols.md,
+      and more — scope and contracts are thoroughly documented.'
+  availability:
+    current: A1
+    target: A3
+    confidence: medium
+    rationale: Python package with `make test`; no packaged distribution or hosted service confirmed in
+      this sweep.
+external_evidence:
+  completeness:
+    level: C2
+    confidence: low
+    basis: scope_vs_intent_and_consumer_expectations
+    satisfied_expectations:
+    - registration/identity/factor model documented
+    - entitlement claims and access-profile model (hats/realms/services/assets) documented
+    - canon mapping and interface card present
+    broken_expectations: []
+    out_of_scope_expectations: []
+  reliability:
+    level: R0
+    confidence: low
+    basis: consumer_quality_signals
+    known_reliability_risks:
+    - breadth of documented scope not independently verified against implementation completeness in this
+      sweep
+discovery:
+  intent: Provide a headless, multi-application, multi-tenant user-management engine covering the full
+    registration-to-entitlement lifecycle, reusable across NetKingdom-family applications.
+  includes:
+  - multi-tenant registration and identity/factor model
+  - entitlement claims and hats/realms/services/assets access profiles
+  - onboarding journeys and welcome protocols
+  excludes:
+  - IAM/OIDC protocol implementation itself (see key-cape, net-kingdom)
+  assumptions: []
+  use_cases: []
+  research_memos: []
+availability:
+  current_level: A1
+  target_level: A3
+  current_artifacts:
+  - Python package (`user-engine`)
+  target_artifacts: []
+  consumption_modes:
+  - library import
+relations:
+  depends_on: []
+  supports: []
+  related_to: []
+evidence:
+  documentation:
+  - docs/contracts.md
+  - docs/registration-identity-and-factor-model.md
+  - docs/canon-mapping.md
+  tests:
+  - tests/
+  consumer_feedback: []
+  bug_reports: []
+  incidents: []
+consumer_guidance:
+  recommended_for:
+  - multi-tenant applications needing a headless user/identity/entitlement engine
+  not_recommended_for:
+  - needs for the IAM/OIDC protocol layer itself (see key-cape/net-kingdom)
+  known_limitations:
+  - large documented scope; implementation completeness not independently verified in this sweep
+promotion_history: []
+---
+
+# Headless Multi-Tenant User Engine
+
+## Overview
+
+`user-engine` is a headless, multi-application, multi-tenant user-management engine: registration, identity/factor models, prepared accounts and entitlement claims, hats/realms/services/assets access profiles, and onboarding journeys, documented in unusual depth for its size.
+
+## Assessment notes
+
+### Discovery
+
+Unusually large documentation set for its size: docs/development.md, configuration.md, contracts.md, canon-mapping.md, canon-interface-card.yaml, family-dataspace-onboarding.md, registration-identity-and-factor-model.md, prepared-accounts-and-entitlement-claims.md, hats-realms-services-assets-access-profiles.md, onboarding-journeys-and-welcome-protocols.md, and more — scope and contracts are thoroughly documented.
+
+### Availability
+
+Python package with `make test`; no packaged distribution or hosted service confirmed in this sweep.
+
+### Completeness
+
+First-pass honest assessment from the REUSE-WP-0017 coverage campaign
+(reuse-surface). No external consumer feedback exists yet; levels reflect
+scope-vs-intent documentation quality, not internal code quality.
+
+### Reliability
+
+No production consumer telemetry exists yet; reliability level is
+intentionally conservative pending REUSE-WP-0019 reuse-telemetry evidence.
+
+## Promotion checklist
+
+- [x] ID follows `capability.<domain>.<name>` pattern
+- [x] Maturity enums match `specs/CapabilityMaturityStandard.md`
+- [x] `external_evidence` is populated separately from `maturity`
+- [ ] Relations reference valid capability IDs (none yet)
+- [x] Index entry added in `registry/indexes/capabilities.yaml`