diff --git a/.github/copilot-instructions.md b/.github/copilot-instructions.md
index fbf5c442531..75e6f46f14c 100644
--- a/.github/copilot-instructions.md
+++ b/.github/copilot-instructions.md
@@ -1,5 +1,41 @@
# Copilot Code Review Instructions
+## Review Policy — Read This First
+
+You are a code reviewer for a large TypeScript/Next.js/React monorepo. Your reviews must be **low-noise and high-signal**. The team acts on fewer than 20% of default Copilot suggestions, so every comment you leave must earn its place.
+
+### Confidence Threshold
+
+Only comment when you are **>85% confident** the issue is a real bug, security vulnerability, or logic error. If you are unsure, do not comment. Silence is better than noise.
+
+### What NOT to Comment On
+
+Our CI pipeline already validates the following. **Never comment on these topics:**
+
+- **Formatting or whitespace** — Prettier runs on every PR
+- **Linting issues** — ESLint with auto-fix runs on every PR
+- **Type errors** — TypeScript strict-mode typecheck runs on every PR
+- **Typos or spelling** — Automated typo detection runs on every PR
+- **Missing tests for trivial changes** — Handled by topic-specific test instructions
+- **Import ordering or grouping** — Handled by linter
+- **Naming style preferences** (camelCase vs snake_case debates) — Follow existing file conventions
+- **Accessibility attributes on shadcn/Radix UI components** — See `studio-shadcn-components.instructions.md` for details
+
+### What TO Comment On (Priority Order)
+
+1. **Logic errors and bugs** — Off-by-one, null derefs, wrong conditional, unreachable code, incorrect early returns
+2. **Security vulnerabilities** — XSS, SQL injection, auth bypass, secrets in code, unsafe `dangerouslySetInnerHTML`
+3. **Race conditions and async bugs** — Missing `await`, unhandled promise rejections, stale closures, effect cleanup issues
+4. **Data loss risks** — Destructive operations without confirmation, missing error handling on writes
+5. **API contract violations** — Wrong HTTP method, missing auth headers, incorrect request/response shapes
+
+### Comment Style
+
+- **Be advisory, not prescriptive.** Use "Consider..." or "This may..." — never demand changes.
+- **One comment per distinct issue.** Do not leave multiple comments about the same underlying problem.
+- **No self-contradictions.** If you suggest a change, do not then flag a problem with your own suggestion.
+- **Do not comment on individual commits.** Review the final state of the PR diff only.
+
## Repo Context
This is a TypeScript/Next.js/React monorepo:
@@ -11,16 +47,13 @@ This is a TypeScript/Next.js/React monorepo:
## Topic-Specific Guidelines
-Detailed review rules are in path-specific instruction files under `.github/instructions/`:
+Path-specific rules in `.github/instructions/`:
- **Telemetry**: `studio-telemetry.instructions.md` — event naming, property conventions, feature flag measurement
- **Testing**: `studio-testing.instructions.md` — test strategy, extraction patterns, coverage expectations
+- **Error Handling**: `studio-error-handling.instructions.md` — error classification, `ErrorMatcher` usage
+- **E2E Tests**: `studio-e2e-tests.instructions.md` — selector priority, anti-patterns (`waitForTimeout`, `force: true`)
+- **Composition Patterns**: `studio-composition-patterns.instructions.md` — avoid boolean props, use compound components
+- **shadcn/Radix Components**: `studio-shadcn-components.instructions.md` — accessibility handled by primitives, do not flag
-These files are scoped to `apps/studio/` and applied automatically by Copilot during reviews.
-
-## References
-
-For the full, authoritative versions of these standards:
-
-- Telemetry: `.claude/skills/telemetry-standards/SKILL.md`
-- Testing: `.claude/skills/studio-testing/SKILL.md`
+These files are scoped to `apps/studio/` and applied automatically during reviews.
diff --git a/.github/instructions/studio-composition-patterns.instructions.md b/.github/instructions/studio-composition-patterns.instructions.md
new file mode 100644
index 00000000000..ff62a03db49
--- /dev/null
+++ b/.github/instructions/studio-composition-patterns.instructions.md
@@ -0,0 +1,93 @@
+---
+applyTo: "apps/studio/**"
+---
+
+# React Composition Patterns Review Rules
+
+All comments are **advisory**.
+
+## Core Principle
+
+Avoid boolean prop proliferation. Use composition (compound components, explicit variants, children) instead of boolean flags to customize behavior.
+
+## When to Flag
+
+### 1. Boolean Prop Proliferation (HIGH)
+
+Flag components accumulating boolean props like `isThread`, `isEditing`, `showAttachments`. Each boolean doubles the state space.
+
+```tsx
+// BAD — unclear intent, combinatorial explosion
+
+
+// GOOD — self-documenting variants
+
+
+```
+
+### 2. Render Props Instead of Children (MEDIUM)
+
+Flag `renderX` callback props when `children` composition would work.
+
+```tsx
+// BAD — render prop for structure
+} />
+
+// GOOD — compound component
+
+
+
+
+```
+
+### 3. UI Coupled to State Implementation (MEDIUM)
+
+Flag UI components calling specific state hooks like `useGlobalChannelState()` directly. The provider should own the state implementation; UI should only use a generic context interface.
+
+```tsx
+// BAD — UI knows HOW state is managed
+const state = useGlobalChannelState(channelId)
+
+// GOOD — provider owns implementation, UI uses context
+
+ {/* reads from context */}
+
+```
+
+### 4. State Trapped in Child Components (MEDIUM)
+
+Flag state that siblings or dialogs need but can't access without prop drilling or refs. Lift it into a provider.
+
+```tsx
+// BAD — sibling can't access state
+function ForwardComposer() {
+ const [state, setState] = useState(init)
+}
+// ForwardButton is a sibling and can't reach state
+
+// GOOD — provider at shared ancestor
+
+ {/* can access state */}
+ {/* can also access state */}
+
+```
+
+### 5. React 19 API Updates
+
+Flag `forwardRef` and `useContext` in new code — use `ref` as a regular prop and `use()` instead.
+
+```tsx
+// BAD
+const Input = forwardRef((props, ref) => )
+const value = useContext(MyContext)
+
+// GOOD
+function Input({ ref, ...props }) { return }
+const value = use(MyContext)
+```
+
+## Key Principle
+
+Lift state → Compose UI → Inject via generic context → No boolean prop proliferation.
+
+Canonical standard: `.claude/skills/vercel-composition-patterns/SKILL.md`
diff --git a/.github/instructions/studio-e2e-tests.instructions.md b/.github/instructions/studio-e2e-tests.instructions.md
new file mode 100644
index 00000000000..1b35fa0dc05
--- /dev/null
+++ b/.github/instructions/studio-e2e-tests.instructions.md
@@ -0,0 +1,79 @@
+---
+applyTo: "e2e/studio/**,apps/studio/**"
+---
+
+# Studio E2E Test Review Rules
+
+All comments are **advisory**.
+
+## Selector Priority (best to worst)
+
+1. **`getByRole` with accessible name** — most robust, tests accessibility
+ ```typescript
+ page.getByRole('button', { name: 'Save' })
+ ```
+
+2. **`getByTestId`** — stable, explicit test hooks
+ ```typescript
+ page.getByTestId('table-editor-side-panel')
+ ```
+
+3. **`getByText` with exact match** — good for unique text
+ ```typescript
+ page.getByText('Data API Access', { exact: true })
+ ```
+
+4. **`locator` with CSS** — use sparingly, more fragile
+ ```typescript
+ page.locator('[data-state="open"]')
+ ```
+
+## Patterns to Flag
+
+- **XPath selectors** — fragile to DOM changes
+ ```typescript
+ // BAD
+ locator('xpath=ancestor::div[contains(@class, "space-y")]')
+ ```
+
+- **Parent traversal with `locator('..')`** — breaks when structure changes
+ ```typescript
+ // BAD
+ element.locator('..').getByRole('button')
+ ```
+
+- **`waitForTimeout`** — never use; wait for something specific instead
+ ```typescript
+ // BAD
+ await page.waitForTimeout(1000)
+
+ // GOOD — wait for UI element
+ await expect(page.getByText('Success')).toBeVisible()
+
+ // GOOD — wait for API response
+ const apiPromise = waitForApiResponse(page, 'pg-meta', ref, 'query?key=table-create')
+ await saveButton.click()
+ await apiPromise
+ ```
+
+- **`force: true` on clicks** — make elements visible first instead
+ ```typescript
+ // BAD
+ await menuButton.click({ force: true })
+
+ // GOOD — hover to reveal, then click
+ await tableRow.hover()
+ await expect(menuButton).toBeVisible()
+ await menuButton.click()
+ ```
+
+- **Broad `filter({ hasText })` on generic elements** — may match multiple elements; scope to specific containers instead
+
+## Good Practices to Encourage
+
+- Scope selectors to containers: `page.getByTestId('side-panel').getByRole('switch')`
+- Add `aria-label` to icon-only buttons in source code for better test selectors
+- Use `test.describe.configure({ mode: 'serial' })` for tests sharing database state
+- Add messages to expects: `await expect(locator, 'why').toBeVisible({ timeout: 30000 })`
+
+Canonical standard: `.claude/skills/e2e-studio-tests/SKILL.md`
diff --git a/.github/instructions/studio-error-handling.instructions.md b/.github/instructions/studio-error-handling.instructions.md
new file mode 100644
index 00000000000..bb4144e46f4
--- /dev/null
+++ b/.github/instructions/studio-error-handling.instructions.md
@@ -0,0 +1,43 @@
+---
+applyTo: "apps/studio/**"
+---
+
+# Studio Error Handling Review Rules
+
+All comments are **advisory**.
+
+## Architecture
+
+Errors flow: `handleError()` → throws typed subclass → React Query catches → `ErrorMatcher` reads `errorType` → renders troubleshooting. The component does an O(1) lookup — it never does regex matching.
+
+## When to Flag
+
+- PR passes `error.message` instead of the full `error` object to `ErrorMatcher` — the class type is lost
+- PR puts regex patterns in `error-mappings.tsx` — they belong in `data/error-patterns.ts`
+- PR uses `Object.assign` to stamp `errorType` on an error — should throw a proper subclass instead
+- PR passes a raw URL string for support links — should use `supportFormParams={{ projectRef }}`
+- PR puts the page title inside the error mapping — it belongs on the `` caller
+- PR adds callback props (`onDebugWithAI`, `onRestartProject`) to troubleshooting components — use hooks inside them instead
+
+## Correct Usage
+
+```tsx
+{isError && (
+
+)}
+```
+
+## Key Files
+
+| File | Purpose |
+|------|---------|
+| `data/error-patterns.ts` | `{ pattern, ErrorClass }` array — regex lives here |
+| `types/api-errors.ts` | Error classes, `KnownErrorType` union |
+| `ErrorMatcher.tsx` | Reads `errorType`, looks up mapping, renders |
+| `error-mappings.tsx` | `Record` |
+
+Canonical standard: `.claude/skills/studio-error-handling/SKILL.md`
diff --git a/.github/instructions/studio-shadcn-components.instructions.md b/.github/instructions/studio-shadcn-components.instructions.md
new file mode 100644
index 00000000000..ee61129adb0
--- /dev/null
+++ b/.github/instructions/studio-shadcn-components.instructions.md
@@ -0,0 +1,53 @@
+---
+applyTo: "apps/studio/**"
+---
+
+# shadcn/Radix UI Component Review Rules
+
+All comments are **advisory**.
+
+## Core Principle
+
+This project uses **shadcn/ui** components built on **Radix UI** primitives (from `packages/ui/`). These components provide comprehensive accessibility out-of-the-box. **Do not flag missing accessibility attributes that are already handled by the underlying Radix primitives.**
+
+## Components with Built-In Accessibility — Do NOT Flag
+
+The following components (imported from `ui`) already handle ARIA roles, keyboard navigation, focus management, and screen reader support automatically via Radix UI primitives:
+
+| Component | What Radix Handles |
+|-----------|-------------------|
+| `Dialog`, `AlertDialog` | `role="dialog"`, `aria-modal`, focus trapping, ESC to close |
+| `DropdownMenu`, `ContextMenu` | `role="menu"` / `role="menuitem"`, arrow key navigation |
+| `Select` | `role="combobox"`, `aria-expanded`, keyboard selection |
+| `Tabs` | `role="tablist"` / `role="tab"` / `role="tabpanel"`, `aria-selected`, arrow keys |
+| `Checkbox` | `role="checkbox"`, `aria-checked`, Space to toggle |
+| `RadioGroup` | `role="radio"`, `aria-checked`, arrow key navigation |
+| `Switch` | `role="switch"`, `aria-checked`, keyboard toggle |
+| `Tooltip` | Trigger/content association, show/hide timing |
+| `Accordion`, `Collapsible` | `aria-expanded`, Enter/Space to toggle |
+| `Popover`, `HoverCard` | Focus management, dismiss on ESC |
+| `Slider` | `role="slider"`, `aria-valuemin/max/now`, arrow keys |
+| `Toggle`, `ToggleGroup` | `aria-pressed`, keyboard support |
+| `ScrollArea` | Accessible scrollbar replacement |
+| `NavigationMenu` | `role="navigation"`, keyboard navigation |
+
+### Specifically, Never Flag These
+
+- Missing `role` on `Dialog`, `AlertDialog`, `DropdownMenu`, `Select`, `Tabs`, `RadioGroup`, or other Radix-based components — roles are set by the primitive
+- Missing `aria-modal` on `Dialog` or `AlertDialog` — set automatically
+- Missing `aria-expanded` on `Accordion`, `Collapsible`, `Select`, or `DropdownMenu` triggers — managed by Radix state
+- Missing `aria-selected` on `Tabs` — managed by `TabsPrimitive`
+- Missing `aria-checked` on `Checkbox`, `RadioGroup`, or `Switch` — managed by Radix state
+- Missing keyboard event handlers (`onKeyDown`, `onKeyUp`) on interactive Radix components — keyboard support is built-in
+- Missing focus management in `Dialog` or `AlertDialog` — focus trapping is automatic
+- Missing `aria-label` on `DialogClose` or `AlertDialogCancel` — these render a visible `Close`
+
+## What TO Flag
+
+Only flag accessibility issues for:
+
+1. **Custom interactive elements** not using Radix primitives (e.g., a `