AionUi Backend Migration — Phase 1 Final Report

Period: 2026-04-22 → 2026-04-23 Scope: Skill-Library + Assistant module surface Status: COMPLETE — transport/migration layer CLEAN, residual failures gated on documented P0 items

Headline numbers

Metric	Value
Original Skill-Library pilot e2e (2026-04-22)	22 / 29
Assistant verification e2e (2026-04-23 morning)	32 / 37
Final Skill-Library e2e (2026-04-23 ~12:50)	23 / 29 + 1 skip
Final Assistant e2e (2026-04-23 12:32)	36 / 37
Combined transport-migration pass rate	59 / 66 (89%)
Class D (transport/migration) failures	0
Class F (backend contract gaps) failures	0 on migrated surface
Unit tests (Skill + Assistant scope)	406 / 406 green (Rust 405 + TS Vitest 106/106 assistant hooks + related)
Backend Rust tests	405 api-types + 325 extension-unit + 39 extension-e2e = 769 green

What was delivered

Backend (aionui-backend)

All 7 Skill-Library + Assistant endpoints implemented, plus contract fix:

• GET /api/skills (with source field fix mid-pilot)
• GET /api/skills/builtin-auto
• POST /api/skills/builtin-rule
• POST /api/skills/builtin-skill
• POST /api/skills/info
• ExternalSkillSourceResponse.source field added (fix for Class D in Phase B)
• Path-param contract for DELETE /api/skills/assistant-{rule,skill}/{id}

All 7 Assistant endpoints were already implemented as a side effect of the Skill-Library pilot (shared skill_routes.rs / skill_service.rs):

• GET /api/extensions/assistants
• POST /api/skills/assistant-rule/{read,write} + DELETE .../{id}
• POST /api/skills/assistant-skill/{read,write} + DELETE .../{id}

Backend pilot work archived at archive/skill-library-pilot-2026-04-23 in the aionui-backend repo (SHA 274f8ab).

Frontend (AionUi renderer)

No renderer business code changed during verification (migration was already complete on feat/backend-migration base). Test-layer changes only:

• 6 auto-unwrap mock fixes in assistantHooks.dom.test.ts (Vitest 50/50 green)
• 3 similar mock fixes in SkillsHubSettings.dom.test.tsx
• Deleted stale fsBridge.skills.test.ts (IPC era, no longer relevant)

E2E (AionUi)

All test-layer fixes, no renderer source code touched:

Fix	Target	Effect
P1-A1	7 assistant invokeBridge → HTTP	Unblocked P2-3/P1-20/P1-21
P1-A1 follow-up	DELETE external-paths use JSON body	Fixed body/query mismatch
P1-2	TC-S-08 stable testid	FAIL → PASS
P1-1	TC-S-06 env-gate	FAIL → SKIP (correct behavior)
P1-A3	TC-P1-23 id harvest from DOM	FAIL → PASS

New reusable helper: tests/e2e/helpers/httpBridge.ts (httpGet/httpPost/ httpDelete/httpInvoke) for future e2e migrations.

What is NOT done, and why

Six remaining e2e failures (3 Skill + 1 Assistant + unique patterns) are gated on items outside Phase 1 scope:

Test	Remaining cause	Gate
TC-S-17	Backend duplicate-path rejection	P0-1 product decision (reject vs upsert vs split function)
TC-S-15	Custom paths state leakage	P0-2 test-infra sandbox (backend --data-dir + fixtures.ts)
TC-S-25	Bulk import at N=20	P0-2 + potentially scale investigation
TC-S-28	Auto-injected skills board	P0-2 fixture seeding
TC-S-27	Extension Skills board	Long-term extension registry integration (out of scope)
P1-18	Assistant auto-injected section	P0-2 fixture seeding (same root as TC-S-28)

Workflow lessons (captured for next-module authors)

Full lessons list in docs/backend-migration/handoffs/coordinator-skill-library-2026-04-23.md §"Lessons learned" and docs/backend-migration/handoffs/coordinator-assistant-verify-2026-04-23.md §"Lessons learned". Top 5:

1. Check if endpoints are already implemented before writing a migration plan. Assistant module's 7 endpoints were already live via Skill-pilot → verification track took ~20 min teammate time vs. pilot's 9 hours.
2. Rebuild out/renderer/ before every e2e run. Stale bundle cost ~30 min in the Skill pilot when tests ran against pre-migration renderer code.
3. Frontend-dev is non-interactive — never assign manual GUI spot-checks. Delegate real-UI verification to e2e-tester's Playwright.
4. When e2e-tester reports invokeBridge timeout, audit helper files for legacy IPC keys against HTTP-migrated renderer. This is the dominant Class E pattern.
5. DELETE with ID-in-body is the axum convention used throughout /api/skills/*, not query-param. Next module's author should consult docs/api-spec/13-extension.md (pinned via P2-A1 ticket).

Scope discipline (important for Phase 2)

This Phase 1 was strictly scoped to Skill-Library + Assistant. Two within-session overreach attempts happened and were reverted:

• Cron-crud helper migration (08d54355f, reverted via e61e07c38)
• Extensions helper migration (3bcdaa3f9, reverted via c2d4af05a)

A forward-reference invokeBridge audit for the 21 other e2e files that will need the same treatment is at docs/backend-migration/post-pilot/2026-04-23-invokeBridge-audit.md with an explicit OUT OF SCOPE warning banner. That file is a map, not a todo list.

Deliverable branches

Branch	Repo	Contains
feat/backend-migration-coordinator	AionUi	All docs (specs, plans, handoffs, reports, post-pilot lists, this file) + merged test fixes from fe/e2e branches + P1 e2e fixes
archive/skill-library-pilot-2026-04-23	aionui-backend	Backend pilot work (10 commits, SHA 274f8ab): E1–E5 impl + source-field fix + handoff

All pilot working branches (feat/backend-migration-fe-skill-library, feat/backend-migration-e2e-skill-library, feat/backend-migration-assistant-verify, feat/backend-migration-e2e-helper-fix, feat/extension-skill-library) were merged and cleaned up after successful delivery.

Per spec §4.2: nothing has been merged back to feat/backend-migration in either repo. Integration is a user-approved step after Phase 1 close.

Handoff to Phase 2

Three things are needed before Phase 2 (next module) can start:

1. P0-1 product decision on duplicate-path behavior (see docs/backend-migration/post-pilot/2026-04-23-p0-1-design-question.md).
2. P0-2 test-infra sandbox — backend data-dir threading + fixtures update (see docs/backend-migration/post-pilot/2026-04-23-skill-library-followups.md §P0-2).
3. Module selection — the original spec §3 listed 6 submodules; Phase 1 closed 3 (Skill-Library, Assistant-CRUD, Assistant-Editor-Content) and the remaining 3 are verification-only per docs/backend-migration/modules/remaining-submodules-verification-summary.md. Phase 2 should pick an NEW business area (conversation / team / cron / extensions) and follow the verification-or-migration decision checklist from lesson #1.