sectionui

name	sectionui
description	Use for SectionUI and SectionKit iOS development. Covers data-driven UICollectionView architecture in Swift, SKCManager, SKCollectionView, SKCSingleTypeSection, section builders, row mutation, reactive bindings, selection ownership, safe-size measurement, layout plugins, decorations, supplementary views, scroll/page behavior, SwiftUI hosting, nested sections, forwarding hooks, performance caches, and production list/feed/grid patterns.
metadata	{"version":"2.5.7"}

SectionUI Agent Guide

Use this skill to design, implement, review, or debug SectionUI screens. Keep context small: route the task first, open only the matching reference files, then answer with code that follows the framework's data-driven and data-binding model.

Paths like references/... are relative to this skill directory (SectionUI.skills/). If your current working directory is the repository root, prefix paths with SectionUI.skills/.

Version

Current local skill version: v2.5.7.

Reference snapshot: bundled references/ describe the local SectionUI / SectionKit APIs in this repository, not live remote docs. For "latest", compare with the repository source files and the current podspec version before answering.

Install/update entrypoints:

• Release asset: download sectionui.skill.zip from GitHub Releases.
• Update guide: read UPDATE.md; current version is also mirrored in VERSION.md.
• Local Codex: put or symlink SectionUI.skills/ into $REPO_ROOT/.agents/skills/sectionui, $HOME/.agents/skills/sectionui, or another official Codex scan location.
• Repository use: when this repository is the workspace, use SectionUI.skills/ in place.

Operating Principle

SectionUI's default model: after section / manager / view binding, business code manages data and state; cell registration, rendering, sizing, refresh, animation, exposure, selection, and scroll effects should derive from SectionUI sections, models, publishers, and section mutations.

Prefer these defaults:

• Bind through SKCManager or SKCollectionViewController, then mutate source state, section models, selection state, or cache ownership.
• Decide one source of truth per screen slice before writing update code: publisher-owned state uses subscribe(models:); section-owned state uses apply, refresh, append, insert, remove, or delete.
• Use many focused sections instead of one monolithic collection-view controller.
• Prefer wrapperToSingleTypeSection, result builders, supplementary views, decoration plugins, selection state, publisher bindings, and nested sections before writing custom collection plumbing.
• Keep repeated product patterns in app-level wrappers; keep framework usage generic and reusable.
• Name UICollectionView variables sectionView in examples unless matching existing project style requires another name.

Routing

1. Classify the request.

   • Architecture, screen decomposition, source of truth, UI update flow, binding strategy, high-frequency row state, or anti-patterns: use references/TASK_MAP.md, then references/data-driven-best-practices.md.
   • Publishers, @SKPublished, stable cell view models, subscribe(models:), SKBinding, or feedback loops: use references/reactive-binding-recipes.md, with references/data-driven-best-practices.md for ownership decisions.
   • Layout plugins, plugin scope, plugin priority, attribute mutation, pinning, decorations, or invalidation: use references/layout-plugin-execution-recipes.md, then references/layout-decoration-recipes.md only for decoration/frame rules.
   • Concrete API, method, protocol, or type: search references/API_MAP.md, then open the mapped file.
   • Broad behavior such as selection, sizing, scrolling, layout, or SwiftUI hosting: use references/TASK_MAP.md.
   • Unknown domain: start with references/INDEX.md, then refine with rg.

2. Choose the smallest useful reference.

   • Primary task router: references/TASK_MAP.md
   • API keyword router: references/API_MAP.md
   • Full reference index: references/INDEX.md

3. Open only target references.

   • For one topic, open one reference.
   • For cross-domain issues, open at most one adjacent reference unless the code proves more context is needed.
   • Prefer *-recipes.md files for production guidance. Use older broad files like section.md for API overview only.

4. Route actionable feedback.

   • If a reference is stale, an API signature is wrong, an example is broken, a packaging asset is missing, or a useful workflow is absent, use ISSUE_GUIDE.md.
   • Preserve structured fields such as apiName, referencePath, sourcePath, sectionuiVersion, buildInfo, reproductionSteps, and verificationCommands.
   • Redact private app names, local user paths, business module names, private models, screenshots with sensitive UI, logs, and payloads before filing.

Lookup Commands

From the repository root:

• Find a concrete API route: rg -n "SKCManager|refresh\\(|SKSelectionState" SectionUI.skills/references/API_MAP.md
• Search all references by keyword: rg -n "safeSize|reloadKind|pinHeader" SectionUI.skills/references
• List topic files: sed -n '1,220p' SectionUI.skills/references/INDEX.md
• Prepare feedback: sed -n '1,220p' SectionUI.skills/ISSUE_GUIDE.md

From inside SectionUI.skills/, omit the SectionUI.skills/ prefix.

Task Map Summary

User intent	Read first	Adjacent reference
Data-driven architecture, source of truth, screen structure	references/data-driven-best-practices.md	references/production-usage.md
Data binding strategy, publisher-owned vs section-owned updates, high-frequency row visual state	references/data-driven-best-practices.md	references/reactive-binding-recipes.md
Section assembly, optional states, render builders	references/composition-styling-recipes.md	references/render-builder-recipes.md
Manager binding, reload/insert/remove, section identity	references/manager-transaction-recipes.md	references/container-lifecycle-recipes.md
Row refresh, append, insert, delete, reloadKind	references/row-mutation-recipes.md	references/reactive-binding-recipes.md
Publishers, @SKPublished, subscriptions, feedback loops	references/reactive-binding-recipes.md	references/data-driven-best-practices.md
Cell creation, wrappers, UIKit/SwiftUI containers	references/view-cell-container-recipes.md	references/runtime-view-wrapper-recipes.md
Dynamic size, Auto Layout fitting, stale cached size	references/safe-size-measurement-recipes.md	references/adaptive-sizing-recipes.md
Size cache, exposure counts, display tracking	references/cache-exposure-recipes.md	references/rendering-performance-recipes.md
Layout plugin system, scope, priority, invalidation, custom forwards	references/layout-plugin-execution-recipes.md	references/layout-decoration-recipes.md
Decoration frames, backgrounds, z-index, supplementary alignment	references/layout-decoration-recipes.md	references/layout-plugin-execution-recipes.md
Selection state, single/multi-select, reload-safe selection	references/selection-ownership-recipes.md	references/interaction-state-recipes.md
Cell actions, exposure, context menu, prefetch, reorder	references/interaction-state-recipes.md	references/delegate-interaction-recipes.md
Scroll observation, pending scroll, page/zoom	references/navigation-scroll-recipes.md	references/page-zoom-recipes.md
Nested horizontal sections or section-in-cell	references/nested-section-cell-recipes.md	references/container-lifecycle-recipes.md
Custom heterogeneous/raw section	references/custom-section-patterns.md	references/raw-section-wrapper-recipes.md
Debug helpers, cache stores, environment utilities	references/diagnostics-utility-recipes.md	references/advanced-production-tips.md

Code Defaults

Use these patterns unless an existing codebase has a stronger convention:

• Cell: conform to SKLoadViewProtocol and SKConfigurableView.
• Common section: MyCell.wrapperToSingleTypeSection() plus config(models:).
• Manager: call manager.reload(sections) for section replacement and section-local APIs for row mutations.
• Reactive data: bind source state with @SKPublished, SKPublishedValue, or section subscriptions when the publisher owns the section; use stable cell view models for high-frequency visual fields that do not affect height or structure.
• Imperative data: use section row mutation APIs directly when the section owner is already the source of truth.
• Selection: store selection in SKSelectionState, SKSelectionWrapper, or SKSelectionSequence, not visible cells.
• Sizing: prefer safeSize, cellSafeSize, adaptive sizing, and high-performance cache where applicable.
• Plugins: prefer section-level plugins for section-specific behavior, collection-level modes for whole-screen rules, and existing helpers before custom forwards.
• Closures: use [weak self] when capturing view controllers or long-lived owners.

Boundaries

• Do not invent API signatures. Confirm concrete methods in references or source files.
• Do not answer from downstream project paths, product names, business modules, page names, or scan indexes.
• Do not recommend direct visible-cell mutation as the normal update path.
• Do not force custom UICollectionViewDataSource / UICollectionViewDelegate plumbing when SectionUI wrappers, forwarding hooks, or plugins cover the behavior.
• If a reference and source disagree, trust source for signature and mention the reference may be stale.

Feedback Workflow

Use ISSUE_GUIDE.md when the user reports a requirement, bug, missing recipe, confusing behavior, stale docs, broken example, or packaging/install issue that should become a repository issue.

Feedback defaults:

• Reproduce locally when practical with rg, unit tests, package build, SwiftPM tests, or Xcode/simulator evidence.
• Prefer scenario-specific GitHub issue forms under .github/ISSUE_TEMPLATE/.
• Keep reproducibility-critical public facts: API names, versions, sanitized stack traces, minimal code, and command output.
• Remove private app source, product names, patient/user data, analytics keys, internal URLs, screenshots with sensitive UI, and full production logs.
• If using gh, create issues with gh issue create --repo linhay/SectionKit --template <form>.

Maintenance

Use script-backed workflows for distribution and validation:

• Package skill: python3 SectionUI.skills/scripts/package_skill.py --output sectionui.skill.zip --json
• Sync release version: python3 SectionUI.skills/scripts/sync_release_version.py --version 2.5.4
• Validate reference compatibility: python3 SectionUI.skills/scripts/reference_compat.py --json
• Verify release package: python3 SectionUI.skills/scripts/verify_skill_package.py --output sectionui.skill.zip --json
• Validate metadata: python3 -m unittest discover -s SectionUI.skills/tests