flutter-storage

flutter-storage is a skill for Claude Code, Codex from yendangn/flutter-app-builder. It costs 62 tokens per session (470 once invoked), scanned A, original, MIT.

A set of instructions for handling data stored locally in Flutter apps. It covers encrypted secrets, simple settings, and structured SQLite data through separate application-owned interfaces.

In plain words
What is it for?
Use it when adding secure token storage, preferences, SQLite tables, data-access objects, local caches, sync queues, or database migrations.
Why use it?
It prevents sensitive data and database code from being handled inconsistently, while providing rules for schemas, migrations, caching, and offline data.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/yendangn/flutter-app-builder/flutter-storage
Any agent
npx skills add yendangn/flutter-app-builder --skill flutter-storage
Clone the repo
git clone --depth 1 https://github.com/yendangn/flutter-app-builder

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for flutter-storage

README.md
[![agentmods](https://agentmods.dev/badge/skills/yendangn/flutter-app-builder/flutter-storage.svg)](https://agentmods.dev/skills/yendangn/flutter-app-builder/flutter-storage)
Your own site
<a href="https://agentmods.dev/skills/yendangn/flutter-app-builder/flutter-storage"><img src="https://agentmods.dev/badge/skills/yendangn/flutter-app-builder/flutter-storage.svg" alt="Measured on agentmods" height="20"></a>
Per session 62 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 470 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00062 $0.00470
Opus 5 $0.00031 $0.00235
Sonnet 5 $0.00012 $0.00094
Haiku 4.5 $0.00006 $0.00047

Measured 3d ago against content hash 29da70684977, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

flutter-storage scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/flutter-storage/SKILL.md · 43 lines

What it actually says

Flutter Storage

Full reference: template.md

Key rules

  • Three storage tiers, each behind an app-owned interface:
    1. SecureStorage — wraps flutter_secure_storage. Tokens, credentials, sensitive data only.
    2. KeyValueStore — wraps shared_preferences. Non-sensitive settings, flags, simple values.
    3. AppDatabase — Drift ORM over SQLite. Structured data, offline cache, sync queue.
  • Never import flutter_secure_storage, shared_preferences, or drift outside their designated wrapper/impl files.
  • Drift tables are defined in app_database.dart with @DriftDatabase(tables: [...]). DAOs are separate files per entity.
  • DAO files annotated @DriftAccessor(tables: [...]). Each DAO exposes typed CRUD methods — never raw SQL in repository code.
  • AppDatabase is a LazyDatabase backed by sqlite3_flutter_libs. Always created once as a singleton.
  • Run dart run build_runner build --delete-conflicting-outputs after any Drift schema change.

Files

lib/src/core/storage/
  secure_storage.dart            ← interface
  secure_storage_impl.dart       ← only import of flutter_secure_storage
  key_value_store.dart           ← interface
  key_value_store_impl.dart      ← only import of shared_preferences
lib/src/core/database/
  app_database.dart              ← @DriftDatabase, table definitions, LazyDatabase
  app_database.g.dart            ← generated
  daos/
    <entity>_dao.dart            ← @DriftAccessor, typed CRUD
    <entity>_dao.g.dart          ← generated

Co-load with

  • flutter-di — register as lazySingleton
  • flutter-offline — Drift is the offline cache backend
  • flutter-authSecureStorage stores tokens
Files

What ships with it

6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 3d ago First seen · 43 lines · 62 tokens per session scan A 29da70684977

Subscribe to this mod's changes

flutter-storage is a skill published in the GitHub repository yendangn/flutter-app-builder (5 stars, last pushed 2mo ago), licensed MIT. It adds 62 tokens to every session and 470 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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