Agent skill

Flutter Caching Data

Implements caching strategies for Flutter apps to improve performance and offline support.

BSD-3-ClauseAuto-check passedMobile

Install Flutter Caching Data

skills CLI

$ npx skills add btwld/superdeck --skill flutter-caching-data -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install btwld/superdeck flutter-caching-data --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/btwld/superdeck.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.agents/skills/flutter-caching-data .claude/skills/flutter-caching-data && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Paste into Claude Code

Install the "flutter-caching-data" agent skill from https://github.com/btwld/superdeck/tree/main/.agents/skills/flutter-caching-data into .claude/skills/flutter-caching-data/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "flutter-caching-data", then confirm the skill loads.

Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

$skill-installer

$skill-installer install https://github.com/btwld/superdeck/tree/main/.agents/skills/flutter-caching-data

Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.

skills CLI

$ npx skills add btwld/superdeck --skill flutter-caching-data -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install btwld/superdeck flutter-caching-data --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/btwld/superdeck.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.agents/skills/flutter-caching-data .agents/skills/flutter-caching-data && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "flutter-caching-data" agent skill from https://github.com/btwld/superdeck/tree/main/.agents/skills/flutter-caching-data into .agents/skills/flutter-caching-data/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "flutter-caching-data", then confirm the skill loads.

Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add btwld/superdeck --skill flutter-caching-data -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install btwld/superdeck flutter-caching-data --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/btwld/superdeck.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.agents/skills/flutter-caching-data .cursor/skills/flutter-caching-data && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "flutter-caching-data" agent skill from https://github.com/btwld/superdeck/tree/main/.agents/skills/flutter-caching-data into .cursor/skills/flutter-caching-data/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "flutter-caching-data", then confirm the skill loads.

Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

gemini skills install

$ gemini skills install https://github.com/btwld/superdeck.git --path .agents/skills/flutter-caching-data

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add btwld/superdeck --skill flutter-caching-data -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install btwld/superdeck flutter-caching-data --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/btwld/superdeck.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.agents/skills/flutter-caching-data .gemini/skills/flutter-caching-data && rm -rf skills-src

Use ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.

Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/

Paste into Gemini CLI

Install the "flutter-caching-data" agent skill from https://github.com/btwld/superdeck/tree/main/.agents/skills/flutter-caching-data into .gemini/skills/flutter-caching-data/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "flutter-caching-data", then confirm the skill loads.

Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

GitHub CLI

$ gh skill install btwld/superdeck flutter-caching-data

Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).

skills CLI

$ npx skills add btwld/superdeck --skill flutter-caching-data -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/btwld/superdeck.git skills-src && mkdir -p .github/skills && cp -r skills-src/.agents/skills/flutter-caching-data .github/skills/flutter-caching-data && rm -rf skills-src

Use ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.

GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/

Paste into GitHub Copilot

Install the "flutter-caching-data" agent skill from https://github.com/btwld/superdeck/tree/main/.agents/skills/flutter-caching-data into .github/skills/flutter-caching-data/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "flutter-caching-data", then confirm the skill loads.

GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add btwld/superdeck --skill flutter-caching-data -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install btwld/superdeck flutter-caching-data --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/btwld/superdeck.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.agents/skills/flutter-caching-data .opencode/skills/flutter-caching-data && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "flutter-caching-data" agent skill from https://github.com/btwld/superdeck/tree/main/.agents/skills/flutter-caching-data into .opencode/skills/flutter-caching-data/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "flutter-caching-data", then confirm the skill loads.

OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

Facts

Skill name: flutter-caching-data
GitHub stars: 129
Token cost: ~2k tokens
SKILL.md length: 705 words
Files: 1
Skills in repo: 23
Repo updated: Sep 28, 2026
First seen: Oct 7, 2026
Licence: BSD-3-Clause

At a glance

Implements caching strategies for Flutter apps to improve performance and offline support.

Works in 3 steps: Instantiate and pre-warm the engine in… → Store it in the FlutterEngineCache. → Retrieve it using withCachedEngine in…
Retaining app data locally to reduce network requests
SKILL.md covers Contents, Selecting a Caching Strategy, Implementing Offline-First… and Managing File System and…, plus 3 more sections
Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Flutter Caching Data is an agent skill from btwld/superdeck. Implements caching strategies for Flutter apps to improve performance and offline support. Use when retaining app data locally to reduce network requests or speed up startup.

Its SKILL.md is about 2k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in Mobile, covering Caching and Cross-platform mobile apps. It works with Flutter, SQLite and Android. The repository describes itself as: Presentation slides for Flutter with Flutter. The licence is BSD-3-Clause.

When your agent uses it

Retaining app data locally to reduce network requests
Speed up startup

Example prompts

“Use the flutter-caching-data skill to implement caching strategies for Flutter apps to improve performance and offline support”
“/flutter-caching-data”

Workflow steps

3 steps, taken from the first numbered list in SKILL.md.

Instantiate and pre-warm the engine in the Application class.
Store it in the FlutterEngineCache.
Retrieve it using withCachedEngine in the FlutterActivity or FlutterFragment.

What it can do on your machine

Read from SKILL.md and the folder at commit 815a746. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md (its code samples are dart and kotlin).
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Flutter Caching Data loads about 2k tokens when it runs. Until then it costs about 49 tokens; SKILL.md has 705 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~49
When it runs · the whole SKILL.md, loaded when a task matches: ~2k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from btwld/superdeck at commit 815a746, republished under its BSD-3-Clause licence (© btwld). 705 words, ~1,977 tokens.

Download SKILL.mdSave it as .claude/skills/flutter-caching-data/SKILL.md (or your agent's skills folder).

name: flutter-caching-data
description: Implements caching strategies for Flutter apps to improve performance and offline support. Use when retaining app data locally to reduce network requests or speed up startup.
metadata.model: models/gemini-3.1-pro-preview
metadata.last_modified: Thu, 12 Mar 2026 22:19:54 GMT

Implementing Flutter Caching and Offline-First Architectures

Selecting a Caching Strategy
Implementing Offline-First Data Synchronization
Managing File System and SQLite Persistence
Optimizing UI, Scroll, and Image Caching
Caching the FlutterEngine (Android)
Workflows

Selecting a Caching Strategy

Apply the appropriate caching mechanism based on the data lifecycle and size requirements.

If storing small, non-critical UI states or preferences: Use shared_preferences.
If storing large, structured datasets: Use on-device databases (SQLite via sqflite, Drift, Hive CE, or Isar).
If storing binary data or large media: Use file system caching via path_provider.
If retaining user session state (navigation, scroll positions): Implement Flutter's built-in state restoration to sync the Element tree with the engine.
If optimizing Android initialization: Pre-warm and cache the FlutterEngine.

Implementing Offline-First Data Synchronization

Design repositories as the single source of truth, combining local databases and remote API clients.

Read Operations (Stream Approach)

Yield local data immediately for fast UI rendering, then fetch remote data, update the local cache, and yield the fresh data.

dart

Stream<UserProfile> getUserProfile() async* {
  // 1. Yield local cache first
  final localProfile = await _databaseService.fetchUserProfile();
  if (localProfile != null) yield localProfile;

  // 2. Fetch remote, update cache, yield fresh data
  try {
    final remoteProfile = await _apiClientService.getUserProfile();
    await _databaseService.updateUserProfile(remoteProfile);
    yield remoteProfile;
  } catch (e) {
    // Handle network failure; UI already has local data
  }
}

Write Operations

Determine the write strategy based on data criticality:

If strict server synchronization is required (Online-only): Attempt the API call first. Only update the local database if the API call succeeds.
If offline availability is prioritized (Offline-first): Write to the local database immediately. Attempt the API call. If the API call fails, flag the local record for background synchronization.

Background Synchronization

Add a synchronized boolean flag to your data models. Run a periodic background task (e.g., via workmanager or a Timer) to push unsynchronized local changes to the server.

Managing File System and SQLite Persistence

File System Caching

Use path_provider to locate the correct directory.

Use getApplicationDocumentsDirectory() for persistent data.
Use getTemporaryDirectory() for cache data the OS can clear.

dart

Future<File> get _localFile async {
  final directory = await getApplicationDocumentsDirectory();
  return File('${directory.path}/cache.txt');
}

SQLite Persistence

Use sqflite for relational data caching. Always use whereArgs to prevent SQL injection.

dart

Future<void> updateCachedRecord(Record record) async {
  final db = await database;
  await db.update(
    'records',
    record.toMap(),
    where: 'id = ?',
    whereArgs: [record.id], // NEVER use string interpolation here
  );
}

Optimizing UI, Scroll, and Image Caching

Image Caching

Image I/O and decompression are expensive.

Use the cached_network_image package to handle file-system caching of remote images.
Custom ImageProviders: If implementing a custom ImageProvider, override createStream() and resolveStreamForKey() instead of the deprecated resolve() method.
Cache Sizing: The ImageCache.maxByteSize no longer automatically expands for large images. If loading images larger than the default cache size, manually increase ImageCache.maxByteSize or subclass ImageCache to implement custom eviction logic.

Scroll Caching

When configuring caching for scrollable widgets (ListView, GridView, Viewport), use the scrollCacheExtent property with a ScrollCacheExtent object. Do not use the deprecated cacheExtent and cacheExtentStyle properties.

dart

// Correct implementation
ListView(
  scrollCacheExtent: const ScrollCacheExtent.pixels(500.0),
  children: // ...
)

Viewport(
  scrollCacheExtent: const ScrollCacheExtent.viewport(0.5),
  slivers: // ...
)

Show full SKILL.md (307 more words)Show less

Avoid overriding operator == on Widget objects. It causes O(N²) behavior during rebuilds.
Exception: You may override operator == only on leaf widgets (no children) where comparing properties is significantly faster than rebuilding, and the properties rarely change.
Prefer using const constructors to allow the framework to short-circuit rebuilds automatically.

Caching the FlutterEngine (Android)

To eliminate the non-trivial warm-up time of a FlutterEngine when adding Flutter to an existing Android app, pre-warm and cache the engine.

Instantiate and pre-warm the engine in the Application class.
Store it in the FlutterEngineCache.
Retrieve it using withCachedEngine in the FlutterActivity or FlutterFragment.

kotlin

// 1. Pre-warm in Application class
val flutterEngine = FlutterEngine(this)
flutterEngine.navigationChannel.setInitialRoute("/cached_route")
flutterEngine.dartExecutor.executeDartEntrypoint(DartEntrypoint.createDefault())

// 2. Cache the engine
FlutterEngineCache.getInstance().put("my_engine_id", flutterEngine)

// 3. Use in Activity/Fragment
startActivity(
  FlutterActivity.withCachedEngine("my_engine_id").build(this)
)

Note: You cannot set an initial route via the Activity/Fragment builder when using a cached engine. Set the initial route on the engine's navigation channel before executing the Dart entrypoint.

Workflows

Workflow: Implementing an Offline-First Repository

Follow these steps to implement a robust offline-first data layer.

Task Progress:
- Define the data model with a synchronized boolean flag (default false).
- Implement the local DatabaseService (SQLite/Hive) with CRUD operations.
- Implement the remote ApiClientService for network requests.
- Create the Repository class combining both services.
- Implement the read method returning a Stream<T> (yield local, fetch remote, update local, yield remote).
- Implement the write method (write local, attempt remote, update synchronized flag).
- Implement a background sync function to process records where synchronized == false.
- Run validator -> review errors -> fix (Test offline behavior by disabling network).

Workflow: Pre-warming the Android FlutterEngine

Follow these steps to cache the FlutterEngine for seamless Android integration.

Task Progress:
- Locate the Android Application class (create one if it doesn't exist and register in AndroidManifest.xml).
- Instantiate a new FlutterEngine.
- (Optional) Set the initial route via navigationChannel.setInitialRoute().
- Execute the Dart entrypoint via dartExecutor.executeDartEntrypoint().
- Store the engine in FlutterEngineCache.getInstance().put().
- Update the target FlutterActivity or FlutterFragment to use .withCachedEngine("id").
- Run validator -> review errors -> fix (Verify no blank screen appears during transition).

Files

Just SKILL.md in .agents/skills/flutter-caching-data of btwld/superdeck.

Open the folder on GitHubat commit 815a746

Compare with similar skills

Flutter Caching Data next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Flutter Caching Data compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Flutter Caching Data this skillbtwld/superdeck	129	—	~2k	Automated safety check: Pass	BSD-3-Clause	9 days ago
Mobile App Builderrevfactory/harness-100	1.3k	—	~1.8k	Automated safety check: Pass	Apache-2.0	6 mo ago
Frb Android Emulator Preparefzyzcjy/flutter_rust_bridge	5.4k	—	~2.1k	Automated safety check: Notes	MIT	yesterday
Claude Android NinjaDrjacky/claude-android-ninja	124	—	~5.2k	Automated safety check: Pass	Apache-2.0	8 days ago
Web3authWeb3Auth/web3auth-examples	144	—	~1.4k	Automated safety check: Pass	MIT	4 days ago
SimdeckNativeScript/SimDeck	152	—	~3.6k	Automated safety check: Pass	MIT	26 days ago

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Questions about Flutter Caching Data

What does Flutter Caching Data do?

Implements caching strategies for Flutter apps to improve performance and offline support. Flutter Caching Data is an agent skill from btwld/superdeck. Implements caching strategies for Flutter apps to improve performance and offline support.

When should I use Flutter Caching Data?

Flutter Caching Data fits situations like: retaining app data locally to reduce network requests; speed up startup.

How do I install Flutter Caching Data in Claude Code?

Run `npx skills add btwld/superdeck --skill flutter-caching-data -a claude-code`. Or copy the skill folder (.agents/skills/flutter-caching-data in btwld/superdeck) into .claude/skills/flutter-caching-data in your project. Claude Code loads it when a task matches its description.

How do I install Flutter Caching Data in Codex?

Run `npx skills add btwld/superdeck --skill flutter-caching-data -a codex`. Or copy the skill folder (.agents/skills/flutter-caching-data in btwld/superdeck) into .agents/skills/flutter-caching-data in your project. Codex loads it when a task matches its description.

Can I use Flutter Caching Data in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add btwld/superdeck --skill flutter-caching-data -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/flutter-caching-data, .gemini/skills/flutter-caching-data, .github/skills/flutter-caching-data and .opencode/skills/flutter-caching-data in your project.

What does Flutter Caching Data need to run?

SKILL.md names no scripts, command-line tools or credentials: Flutter Caching Data is instructions for the agent only.

Does Flutter Caching Data access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Flutter Caching Data safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Flutter Caching Data use?

Flutter Caching Data is published under the BSD-3-Clause licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Flutter Caching Data use?

About 2k tokens (SKILL.md is roughly 7.9k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Flutter Caching Data?

Skills that share tags, products or a category with Flutter Caching Data: Mobile App Builder (revfactory/harness-100, 1.3k stars), Frb Android Emulator Prepare (fzyzcjy/flutter_rust_bridge, 5.4k stars), Claude Android Ninja (Drjacky/claude-android-ninja, 124 stars) and Web3auth (Web3Auth/web3auth-examples, 144 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Flutter Caching Data?

btwld (a GitHub organization) maintains it in btwld/superdeck, which has 129 GitHub stars. The repository holds 23 skills in this directory. The repository was last updated on September 28, 2026.

Source: btwld/superdeck on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install Flutter Caching Data

Facts

At a glance

What it does

When your agent uses it

Example prompts

Workflow steps

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Implementing Flutter Caching and Offline-First Architectures

Contents

Selecting a Caching Strategy

Implementing Offline-First Data Synchronization

Read Operations (Stream Approach)

Write Operations

Background Synchronization

Managing File System and SQLite Persistence

File System Caching

SQLite Persistence

Optimizing UI, Scroll, and Image Caching

Image Caching

Scroll Caching

Widget Caching

Caching the FlutterEngine (Android)

Workflows

Workflow: Implementing an Offline-First Repository

Workflow: Pre-warming the Android FlutterEngine

Files

Compare with similar skills

Similar skills

More from btwld/superdeck

Related

Questions about Flutter Caching Data