# Findings: Server-Backed Brand Kit Canvas Context

## Requirements
- The previous implementation is frontend-only and insufficient for durable user ownership.
- The canvas header needs a compact Brand Kit selector beside the project name.
- The selector contains None plus the authenticated user's Brand Kits and shows the active selection.
- Agent Chat and every new session within that canvas must use the selected Brand Kit as a creative baseline.
- The Home prompt composer also needs a Brand Kit picker. Its empty state provides a direct `创建 Brand Kit` action.

## Initial Decisions
- Persist the project-to-kit relation on the server and inject context server-side so clients cannot silently omit it.
- Preserve the existing restrained Moteva canvas visual language and use the supplied interaction hierarchy without copying product identifiers.

## Repository Discovery
- The server is an existing go-zero REST service with one `img_infinite_canvas.api`, generated handlers/types, thin logic files, and a shared `ServiceContext`.
- PostgreSQL persistence is SQLC-based (`server/sqlc.yaml`, `schema.sql`, `query.sql`) while memory storage supports local development and tests.
- The local `mcp-zero` binary and `/Users/liangxu/go/bin/goctl` are both available; API generation can follow the required spec-first workflow.
- The frontend Brand Kit implementation is still uncommitted and browser-local, so it must be migrated carefully without discarding its editor/model work.
- Playwright prerequisites are available, and the user has an authenticated browser session for final integration testing.
- `design.Project` is the common object passed through chat planning, conversation, and image-prompt generation, so adding resolved Brand Kit context there gives one reliable injection point for all Agent Chat flows.
- `design.Repository` currently owns project CRUD; both memory and PostgreSQL implementations enforce user scope through `design.UserIDFromContext`.
- Projects currently persist title/canvas/thread state but no `brandKitId`; SQLC generates PostgreSQL accessors from `schema.sql` and `query.sql`.
- Agent messages already carry `thread_id`, and the request can start a new thread; the selected kit should therefore be loaded from the project before every chat operation rather than copied into individual messages.
- `DesignService.AgentChat` reloads the project before planning every turn, then passes project-scoped copies to planning, research, conversation, and background generation. Hydrating the Brand Kit immediately after that load covers existing and newly created threads.
- Creative-agent prompt builders already centralize project identity through `projectBriefContext`, while deterministic/fallback image generation reads `design.Project`; Brand Kit context should be added to both centralized context builders and agent memory.
- Project creation has synchronous and asynchronous paths. Both should accept an optional requested kit and otherwise bind the authenticated user's default kit server-side.
- An explicit Home selection should override the default kit; the server must still verify that the selected kit belongs to the authenticated user.
- Home's composer has a compact action row with existing Radix Popovers for model selection, making a palette-icon Brand Kit popover a native extension rather than a new interaction pattern.
- Home currently appends a browser-local default kit prompt. This must be removed once project creation sends `brandKitId`, preventing duplicated or client-controlled brand instructions.
- Frontend `Project` and canvas snapshot merge paths need to preserve `brandKitId`; the direct project-document endpoint remains the authoritative source.
- Canvas workspace already centralizes title rendering and project updates, so the selector can live beside `WorkspaceTitle` and update the same in-memory project after a binding API call.
- The existing Brand Kit document is already versioned and contains the requested grouped colors, uploaded fonts with optional sizes/descriptions, logos, cover, references, voice, and visual direction. The server can validate this exact version-1 shape and compile it into authoritative prompt context.
- The project repository abstraction has a single `Save` operation and user-scoped `Get`; adding `BrandKitID` to `design.Project` will naturally flow through memory/cache/realtime wrappers as long as PostgreSQL mapping and API mappers are updated.
- `ServiceContext` constructs storage-specific modules beside the project repository. A dedicated Brand Kit service/store should follow the existing auth/sharing module pattern and use the same configured memory/PostgreSQL driver.
- All `/api/*` routes except the explicit public allowlist already require a valid bearer session, so new `/api/brand-kits` routes automatically enforce login before logic runs.
- SQLC is installed locally. The existing PostgreSQL repository runs the idempotent schema at startup, making schema/query changes plus SQLC regeneration the consistent persistence path.
- Direct image mode currently sends the raw user prompt to image generation, bypassing the creative planner. Brand context therefore must also be added to the direct/fallback image prompt builders, not only long-term memory and `projectBriefContext`.
- Asynchronous create/follow-up jobs reload projects from persistence, so Brand Kit context must be re-resolved inside those job execution paths; hydrating only the initial HTTP turn would be insufficient.
- Uploaded Brand Kit logos, cover images, and reference images are resolved server-side as ephemeral project inputs. Image generation appends them after user-supplied references so existing inline reference numbering remains stable.