Coordinator Handoff — Snake-Case Wire Realignment — 2026-04-24

Coordinator branch (AionUi): feat/backend-migration-coordinator — this commit Feature branch (AionUi): feat/backend-migration-builtin-skills @ 64bddde5c Feature branch (aionui-backend): feat/builtin-skills @ 326e228 PRs: Per user instruction — none raised.

What shipped

Reverted H1 (04f1537)'s directional mistake on the builtin-skill pilot. Removed all 21 #[serde(rename_all = "camelCase")] attributes from aionui-backend/crates/aionui-api-types/src/skill.rs. Flipped 18+ backend tests to assert snake_case. Audited + flipped 13 JSON-body keys in skills_builtin_e2e.rs and 14 in assistants_e2e.rs. On the frontend, flipped listAvailableSkills response shape, materializeSkillsForAgent request + response, plus AcpSkillManager / initAgent access sites, plus incidentally the narrowed SkillInfo types in SkillsHubSettings.tsx and AssistantSettings/types.ts. E2E Playwright suite rerun 8/8 green on the realigned pair.

Why

H1 was landed during the T3 run-1 of the builtin-skill pilot to fix a contract mismatch. I mis-diagnosed the fix direction: I asked backend-dev to make skill.rs accept camelCase. origin/main's dae96f8 ("refactor: remove camelCase serde rename from all aionui-api-types structs") had already established snake_case as the project-wide wire convention. My H1 created a camelCase island inside an otherwise snake_case project. Subsequent main→feat merges didn't clean it up (the merge's --theirs resolution only touched 4 text conflicts; skill.rs camelCase attrs were non-conflicting additions). Frontend merge from feat/backend-migration brought over snake_case for most fields but kept camelCase on fields the pilot introduced (materialize, relativeLocation, isCustom, dirPath). Live probes confirmed the mis-alignment end-to-end.

Role deliverables

Role	Final SHA	Deliverable
coordinator	this commit	spec, plan, merge, packaging smoke, this handoff
backend-dev	326e228	T1: removed 21 rename_all; flipped 18 tests; audited 13 skills_builtin_e2e + 14 assistants_e2e JSON keys; live probe all directions
frontend-dev	dba2ef499	T2: flipped 5 wire-surface sites; incidental SkillInfo type narrowing; Vitest + E2E L259-260
e2e-tester	64bddde5c	T3: audited + flipped 5 more camelCase classes in e2e fixtures; 8/8 green on final run; report appended "Run 3 — post-realign"

Packaging smoke — coordinator T4.2

Staged target/release/aionui-backend alone in mktemp -d (no sibling assets/ dir). Probed:

Probe	Result
POST /api/skills/builtin-skill body {file_name:...}	200 ✅
GET /api/skills row keys	[description, is_custom, location, name, relative_location, source] ✅
POST /api/skills/materialize-for-agent body {conversation_id, enabled_skills}	200, data.dir_path populated ✅

Release-binary self-contained; snake_case on the wire end-to-end.

Merge conflicts during T4.1

One conflict in src/common/adapter/ipcBridge.ts around the listBuiltinAutoSkills / materializeSkillsForAgent block. HEAD (coord) had pre-existing camelCase, incoming (builtin-skills) had the fixed snake_case. Resolved with git checkout --theirs — incoming wins because realigning to snake_case is the whole point of this pilot. No manual hand-merge needed.

In-flight issues noted (not blocking)

1. camelCase residue in other endpoint surfaces. While doing T4.1 merge, noticed several camelCase wire fields in ipcBridge.ts OUTSIDE this pilot's scope: createUploadFile, the ACP conversation endpoints (setMode, getMode, getModelInfo, setModel, getConfigOptions, setConfigOption). These remain camelCase today. They may or may not be broken at runtime — not audited. Not in this pilot's scope; fresh pilot or targeted audit recommended if user reports issues there.
2. e2e-tester premature task-complete marking. T3 first reported "8/8 green, Task #4 completed" without ever running git commit or git push. Coordinator caught via git status on coord branch and forced the push. Lesson: teammate's "complete" ≠ pushed. Added to playbook.

Lessons captured (playbook appended)

1. Naming-direction bugs need an external oracle before choosing a fix. The right oracle for wire-format questions is git log on crates/aionui-api-types/ — check if there's a recent blanket refactor that sets the project convention (dae96f8 in this case). Had I checked main's history before writing H1, I'd have chosen snake_case immediately.
2. Teammate Task.completed requires verified push. Mental model: complete = (tests pass) AND (git push succeeded) AND (upstream sync verified). Coordinator should verify via git log origin/<branch> before accepting "task complete" claims.
3. Merge conflicts like ipcBridge.ts where one side is a known-bad camelCase block and the other is the pilot's explicit fix: git checkout --theirs is the right call. Don't hand-merge line by line when intent is clear.

Followups (non-blocking)

1. ACP conversation endpoints (setMode et al.) — audit whether their camelCase TS typing actually works against the backend (which probably expects snake_case by dae96f8 convention). Likely broken.
2. createUploadFile camelCase fileName — similar.
3. A project-wide linter on aionui-api-types would have caught H1 before review (as noted in the prior pilot's playbook). Still not landed.
4. Assistant pilot unaffected — assistant.rs in api-types had zero rename_all attrs from the start, and the assistant pilot's frontend correctly uses snake_case. No fallout.

Branch tips

Branch	Repo	SHA
feat/backend-migration-coordinator	AionUi	this commit (merge + handoff)
feat/backend-migration-builtin-skills	AionUi	64bddde5c
feat/builtin-skills	aionui-backend	326e228

No PRs raised per user convention.