Creative Agent Studio #3 — The 134-Commit Megapush: PR1 Launcher, PR2 Workspace, PR3 SSE, PR4 ApproveGate

Tue, 19 May 2026 00:00:00 +0900

Overview

Previous post: #2 — Bitbucket migration, production-readying, React rewrite begins ended with the React infrastructure bootstrapped: empty Zustand store, Vite + Tailwind + TS, three primitives, a <T> i18n component, and a PR1 plan. Twenty-four hours later, 134 non-merge commits had landed four PRs in sequence and produced a working React frontend with real database persistence and live SSE streaming.

The work fell into four PRs and one stack underneath:

PR1 — Launcher (projects CRUD, ProjectCard, NewProjectCard, CreateProjectModal, ProjectGrid)
PR2 — Workspace shell (StageStepper, ProjectSubbar, SessionsRail, Composer, ChatPanel, CanvasPanel placeholder)
PR3 — SSE + chat flow (chat-stream parser, dispatch-sse mapper, useChatStream hook, AgentAvatar, all 7 FeedItem variants, ChatFeed)
PR4 — ApproveSheet + Gates (3-mode drawer, ApproveGateCopy / Scenario / ResearchInput variants)
Underneath — projects, artifacts, diff_history tables; CRUD operations; full REST API; soft-delete semantics

graph TD
 Prev["#2 — bootstrap (752095f)"] --> DB["DB layer <br/> migrations + CRUD + REST"]
 DB --> PR1["PR1 — Launcher <br/> projects survive reload"]
 PR1 --> PR2["PR2 — Workspace shell <br/> StageStepper + SessionsRail + Composer"]
 PR2 --> PR3["PR3 — SSE chat flow <br/> chat-stream + dispatch-sse + 7 feed variants"]
 PR3 --> PR4["PR4 — ApproveSheet <br/> 3-mode drawer + 3 gate variants"]
 PR4 --> End["#3 end (9a2f851) <br/> restore project gate from artifacts"]

One running theme — build the surface bottom-up, and never let a commit cross a layer it shouldn’t.

The Database Layer — Same Day as the UI

Three migrations and a small handful of CRUD modules made projects, artifacts, and diff_history first-class. The first commit (feat(db): add projects, artifacts, diff_history tables via migrations) set the shape:

CREATE TABLE projects (
 id INTEGER PRIMARY KEY,
 title TEXT NOT NULL,
 brand TEXT,
 gate TEXT, -- which gate the project last paused at
 created_at INTEGER NOT NULL,
 updated_at INTEGER NOT NULL,
 deleted_at INTEGER -- soft delete
);

CREATE TABLE artifacts (
 id INTEGER PRIMARY KEY,
 project_id INTEGER REFERENCES projects(id),
 stage TEXT NOT NULL,
 kind TEXT NOT NULL,
 payload TEXT NOT NULL, -- JSON
 evidence_uri TEXT, -- §8.2 — provenance
 created_at INTEGER NOT NULL
);

CREATE TABLE diff_history (
 id INTEGER PRIMARY KEY,
 project_id INTEGER REFERENCES projects(id),
 gate TEXT NOT NULL,
 before TEXT, -- JSON (nullable for first selection)
 after TEXT NOT NULL, -- JSON
 created_at INTEGER NOT NULL
);

Three commits later, the CRUD module landed: createProject, listProjects (active only, updated_at desc), getProject (returns deleted rows for audit), renameProject (partial patch semantics), softDeleteProject (idempotent — no double-flip of deleted_at).

The idempotency rule was specifically tested in fix(db): softDeleteProject preserves deleted_at on idempotent re-call. The original implementation called UPDATE ... SET deleted_at = ? which would overwrite an earlier deletion timestamp if called twice. The fix: UPDATE ... SET deleted_at = ? WHERE deleted_at IS NULL. Small bug, larger principle — soft-delete is a tombstone, not a flag.

Then the REST API came up on top in five commits:

POST /api/projects → createProject
GET /api/projects → listProjects
GET /api/projects/:id → getProject (404 if deleted — fix(api))
PATCH /api/projects/:id → renameProject
DELETE /api/projects/:id → softDeleteProject

A separate fix made GET and PATCH treat soft-deleted projects as 404 (audit-visible via the lower-level CRUD path, but invisible at the REST surface). The diff_history module added appendDiff with a guard against storing literal 'null' strings when after was null — the kind of bug that’s only obvious when you find someone’s project history showing the string "null" rendered in the UI.

PR1 — The Launcher

The user’s first screen. Project list, create-new affordance, search.

A handful of structural commits set up the page architecture:

feat(web): real projects slice (CRUD) — useProjects hook with sort-by-updated
feat(web): add userName + setUserName to ui slice — persisted user name shown in the bilingual greeting
feat(web): add AppTopbar with logo + lang toggle — site chrome
feat(web): add LauncherTopbar + LauncherHero with bilingual greeting
feat(web): add SessionsRail hidden-mode stub (PR2 fills workspace mode)

Then the actual list and creation flow:

feat(web): add ProjectsSearch with bilingual placeholder and count kicker
feat(web): add ProjectCard with progress bar and brand/status
feat(web): add NewProjectCard with dashed border and accent hover
feat(web): add CreateProjectModal with title + optional brand + validation
feat(web): wire ProjectGrid — search filter, modal, navigation

The card progress bar reads from the same gate field the project advanced to — so the launcher card is a live snapshot of how far along each project is. Click → navigate to /projects/:projectId. Done.

What’s clean about this PR is its strict layering: every interactive piece reads from the store, the store reads from the REST API, the REST API reads from the CRUD module, the CRUD module reads from SQLite. No shortcuts. The component itself only knows about the slice.

PR2 — The Workspace Shell

The screen users land on after clicking a project card. Three columns: sessions rail on the left, chat in the middle, canvas placeholder on the right. The actual stage-by-stage workflow lives inside this shell.

Eleven commits, structural:

feat(web): add stage-labels lib (gate ↔ stage + ko/en short/long labels) — the canonical mapping of stages to their bilingual labels, used by both the stepper and the canvas
feat(web): add Session type + real workspace slice (sessions + composer) + store-init test
feat(web): add sessionsPanelOpen + toggleSessionsPanel to ui slice — the rail collapses
feat(web): add StageStepper (6 dots + bilingual long-form label) — the stage progress indicator
feat(web): add ProjectSubbar wrapping StageStepper
feat(web): fill SessionsRail workspace mode (project header + sessions list + new + back)
feat(web): add Composer (pill input + send button, console-log submit only) — chat input, no submission wiring yet
feat(web): add ChatPanel skeleton (header + welcome bubble + Composer)
feat(web): add CanvasPanel placeholder (PR5 fills variants) — explicit deferral
feat(web): assemble WorkspacePage (.shell grid) + swap workspace route

The placeholder pattern is worth noticing. CanvasPanel was added as a placeholder that explicitly said “PR5 fills variants” in the commit message. That deferred a large piece of work without leaving a hole in the layout — the layout was done, the slot was wired, the actual content was a stub that wouldn’t ship to users yet. PR5 could land cleanly because PR2 had reserved its address.

PR3 — SSE Plumbing, Chat Flow, and the Seven Feed Variants

This is the PR that turned a static shell into a live app. Twenty-something commits across three layers — store, plumbing, components.

Store layer

// web/src/store/slices/feed.ts (paraphrased)
type FeedItem =
 | { kind: "user", text: string }
 | { kind: "assistant", text: string }
 | { kind: "streaming", text: string }
 | { kind: "agent_progress", agent: string, status: string }
 | { kind: "stage_complete", stage: string }
 | { kind: "system_error", message: string }
 | { kind: "task_update_note", text: string };

type FeedSlice = {
 feed: FeedItem[];
 appendChunk: (text: string) => void; // streaming
 splitParagraphs: () => void; // streaming → final
 pushAgentProgress: (agent, status) => void;
 pushStageComplete: (stage) => void;
 // ...
};

A discriminated union for the seven feed item types, with per-kind reducers on the slice. Plus a pipeline slice for the gate/stage/context/lastSubmit state, and a workspace slice that gained tasks + activeSubAgents (sink for agent_activity envelopes).

Plumbing layer

Three pure modules and one hook:

feat(web): add chat-stream lib (POST /api/chat + SSE parse + Zod-validated envelopes) — the wire-level parser
feat(web): add dispatch-sse mapper (SSEEnvelope → store actions) — pure mapper, no DOM
feat(web): add useChatStream hook (submit/cancel + AbortController lifecycle) — lifecycle owner

// web/src/hooks/use-chat-stream.ts (paraphrased)
export function useChatStream() {
 const controllerRef = useRef<AbortController | null>(null);

 const submit = useCallback(async (text: string, context: ChatContext) => {
 controllerRef.current?.abort();
 const controller = new AbortController();
 controllerRef.current = controller;

 for await (const envelope of streamChat({ text, context, signal: controller.signal })) {
 dispatchSse(envelope); // store action
 }
 }, []);

 const cancel = useCallback(() => controllerRef.current?.abort(), []);

 return { submit, cancel };
}

The split was: chat-stream parses, dispatch-sse maps, useChatStream owns the lifecycle. Three things, three modules — no module ever did more than one job. Tests for each (tighten test fetch types etc) shipped on the same day.

Component layer

Once envelopes could land in the store, the components rendered them:

feat(web): add AgentAvatar + fix shared/events runtime exports
feat(web): add User/Assistant/Streaming bubble components
feat(web): add AgentProgress + StageComplete + SystemError + TaskUpdateNote
feat(web): add FeedItem discriminated dispatcher (7 variants)
feat(web): add AgentStrip ('Running now' active sub-agents)
feat(web): add ChatFeed (auto-scroll + FeedItem map + welcome empty state)
feat(web): wire ChatPanel to AgentStrip + ChatFeed (replaces static welcome bubble)

The FeedItem dispatcher is the discriminated-union pattern paying off — one place that maps every variant to its component, with exhaustiveness enforced by TS.

The AgentStrip was the materialization of decision 2 from interaction-model.md — “one-line status, no full dashboard.” It shows only the currently-running sub-agents as a horizontal strip across the top of the chat. Not a side panel, not a dashboard, just an inline strip that appears when work is happening and disappears when it isn’t.

PR4 — The ApproveSheet and the Three Gate Variants

The piece that turned the chat-only flow into a chat + approval flow.

The ApproveSheet is a bottom drawer with three modes — collapsed (just the gate prompt), half-open (gate + summary), full (gate + everything). Drag-to-resize via pointer events. Esc collapses. Three gate variants drop into the same shell — each gate stage gets its own variant component.

Twelve commits, structural again:

feat(web): add ApproveGate payload types
feat(web): add approveSheetMode + setApproveSheetMode to ui slice
feat(web): pipeline slice gains copy/scenario history + idx setters — the back-pointer state for switching between historical drafts
feat(web): projects slice gains bumpProjectGate + assert PR4 fields in store-init
feat(web): dispatch-sse pushes copy/scenario history + bumps project gate on stage_complete — the SSE → store glue for gate advance

Then the drawer mechanics:

feat(web): add useApproveSheetDrag hook + PointerEvent jsdom polyfill — the drag-handle hook. PointerEvent isn’t in jsdom by default, so a polyfill shipped alongside.
feat(web): add ApproveSheet base (3-mode drawer + collapse toggle + drag handle)

And the three gate variants:

feat(web): add ApproveGateCopy (grid + select + approve / request-edit) — the user picks one of N copy drafts
feat(web): add ApproveGateScenario (acts list + approve / request-edit) — the user approves or revises a multi-act scenario
feat(web): add ApproveGateResearchInput (question + answer + send) — a different shape: the agent asks the user a research question and waits for a typed answer

Wired together by ApproveGate dispatcher (variant selection + submit wiring), then mounted inside ChatPanel with submit forwarded from WorkspacePage. The user’s flow is now: ask in chat → agent runs → drawer rises with the artifact → approve or revise. Decision 3 from interaction-model.md (gate-based auto-run between stages) is alive.

The End-of-Day State

The last commit of the day (9a2f851 feat(web): restore project gate from artifacts on workspace mount (Slice K)) closed an important loop: when the user reloads the workspace page, the project’s gate state is restored from its persisted artifacts. The day’s work survives a refresh.

Between the underneath stack and PR1–PR4, the React frontend at end-of-day had:

A working launcher (real projects, persisted across reloads)
A workspace shell with a three-column layout
Live chat with SSE streaming
All 7 feed variants rendering
An ApproveSheet drawer with 3 gate variants
Project state surviving reload

The mockup wasn’t deleted yet, but everything it was supposed to demonstrate now ran in React.

Insights

The day worked because every commit respected its layer. The store slices were declared in PR2 with the shape they’d need for PR4. The SSE plumbing in PR3 was three modules — parser, mapper, lifecycle — that could each be tested independently. The ApproveGate variants in PR4 plugged into a dispatcher pattern matching the FeedItem dispatcher from PR3.

The thing that didn’t happen — and was the reason 134 commits in a day was not chaos — was cross-layer commits. No commit added a <button> and a SQL column at the same time. No commit reached up from a CRUD module into a slice. When a commit needed to span layers, it was either preceded by a foundation commit one layer below or followed by an adopter commit one layer above. The discipline turned what would otherwise be a sprint of patchwork into a clean stack of additions.

The mental model worth keeping: fast does not mean shortcut. This day shipped four PRs because of the discipline that let each PR exist, not in spite of it.

Next: the canvas panel, the 5-gate workflow, the key-concept planner, and the revise-mode multi-select pattern that would let users surgically re-run a single card instead of the whole stage.

Sse on ICE-ICE-BEAR-BLOG