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Android Persistence Standards · hoangnguyen0403 | DecimalAI

hoangnguyen0403/android-persistence

SkillScore94Maintained

Implement Room schemas and DataStore preferences with proper async patterns in Android. Use when the primary task is storage schema, DAO, migration, or preference isolation; defer auth-token/security storage, any CoroutineWorker/WorkManager task, Hilt graph wiring, and cache-policy design.

codingby hoangnguyen0403

Links this skill to your agents and keeps it current with the author’s updates.

Automatic

Coding pack

1 · One-time — install the CLI (docs ↗)

pip install decimalai

2 · Get the skill — writes .claude/skills/hoangnguyen0403-android-persistence/SKILL.md

decimalai skills pull hoangnguyen0403-android-persistence --out .claude/skills/

No CLI? Get the same file — curl · raw file

curl -fsSL --create-dirs -o .claude/skills/hoangnguyen0403-android-persistence/SKILL.md https://app.decimal.ai/s/hoangnguyen0403-android-persistence/SKILL.md

Raw file: /s/hoangnguyen0403-android-persistence/SKILL.md ↗ · machine-readable summary at /s/hoangnguyen0403-android-persistence.json ↗

In productionGlobal

how this skill behaves on real traffic · last 30 days

Runs

105

all versions · 30d

Eval pass

100%

global

Used when offered

17%

used / offered · all versions

By model· real traffic, every org · 30d — not the benchmark

Model	Eval pass	Runs
gemini-3.6-flash	100%	12

Anonymized aggregate across every org using this skill — proof from real production use, not a demo.

Does this skill help? · Benchmark: with vs. withoutsign in to run this on your agents

22 test cases from the publisher’s eval.yaml · each run twice on gemini-3.6-flash — with the skill injected, then without · last run 56d ago

Yes — +9% lift-28% tokens0% turns100% of whole cases pass with skill (22/22)

Test case	Without → With	Effect	Δ tokens	Δ turns
case-11	✗→✓	▲ Improved	-37%	0%
case-17	✗→✓	▲ Improved	44%	0%
case-01	✓→✓	＝ Same ✓	-21%	0%
case-02	✓→✓	＝ Same ✓	-48%	0%
case-03	✓→✓	＝ Same ✓	-33%	0%

Showing 5 of 22 cases

SkillSafety

✓ 3 of 3 passed

Code scan15 of 15 checks clean

0 critical · 0 warning · 0 info — scanner v4 — 8/1/2026

live_secretremote_code_executionreverse_shelldata_exfiltrationssrf_metadataagent_snoopinganti_refusaldestructive_commandsobfuscated_unicodeunicode_homoglyphopaque_blobsuspicious_urltool_overreachtrigger_abuseprompt_injection_phrasing

IntentSafe

LLM judge · does the skill do what it claims

ContentClean

LLM judge · policy & harmful-content review

Source

Imported

HoangNguyen0403 / agent-skills-standard

skills/android/android-persistence/SKILL.md

View on GitHub ↗

License Apache-2.0Imported 8/1/2026Version v1Bundled 1 file

Skill contents

references/

SKILL.md

Android Persistence Standards

Priority: P0 (CRITICAL)

1. Configure Room Database

Return Flow<List<T>> for queries, use suspend for Write/Insert.
Keep @Entity data classes simple. Map to Domain models in Repository.
Use @Transaction for multi-table queries (Relations).

See DAO templates for Room DAO patterns.

2. Migrate to DataStore

Replace SharedPreferences with ProtoDataStore (type-safe) or PreferencesDataStore.
Inject singleton DataStore instance via Hilt.

See DAO templates for DataStore migration patterns.

Anti-Patterns

No IO on Main Thread: Room handles dispatchers, but verify Flow collected off-main.
No @Entity in UI Layer: Map to Domain or UI models in Repository.

References

DAO Templates

Illustrative Want to see what hoangnguyen0403/android-persistence would put in front of your model? Preview the rendered body and check its trigger phrases — no LLM call, no signup.

Latest benchmark · publisher runVerified

8/2/2026, 22:05 UTC · 22 cases

Lift

+9%

100% vs 91%

Agent turns

1.0 vs 1.0

Tokens

-28%

1,185.73 vs 1,654

fail → pass · 2pass → pass · 20

Per-case results (22)

Case	Status	Duration (ms)			Turns			Tokens			Tool calls
Case	Status	Without	With	Δ	Without	With	Δ	Without	With	Δ	Without	With	Δ
case-01 I need help setting up a Room DAO and repository for a feature handling user profile settings in our Android app. Could you provide the Kotlin implementation for reading and updating user profile records according to standard persistence guidelines?	pass→pass	11,986	8,270	-31%	1	1	0%	2,532	1,999	-21%	0	0	—
case-02 I am implementing a Room DAO method to fetch all saved bookmark items from the local database for an Android reading app. How should I define the query function signature to stream updates to the UI layer?	pass→pass	9,235	3,812	-59%	1	1	0%	1,671	869	-48%	0	0	—
case-03 We are creating a DAO method in Room to insert new transaction records into the database. What modifier should be applied to the function signature for writing data?	pass→pass	4,671	2,052	-56%	1	1	0%	844	566	-33%	0	0	—
case-04 I'm writing a Room DAO query that fetches a user along with all their associated order history records using `@Relation`. What annotation is required on the DAO query method to ensure atomic transaction execution across tables?	pass→pass	4,280	2,522	-41%	1	1	0%	643	606	-6%	0	0	—
case-05 Our Android app needs to save simple user preference settings such as dark mode toggles and notification flags. What modern Jetpack library should we adopt instead of SharedPreferences for safe, asynchronous preference persistence?	pass→pass	9,513	5,306	-44%	1	1	0%	1,952	1,337	-32%	0	0	—
case-06 We are configuring Hilt dependency injection for our DataStore preferences instance in an Android app module. How should the DataStore instance be scoped in the Hilt module?	pass→pass	6,514	4,457	-32%	1	1	0%	1,214	1,037	-15%	0	0	—
case-07 In an Android architecture review, a developer proposed having the ViewModel observe Room entity data models directly from a Room DAO query. How should the architecture be refactored to align with persistence layering principles?	pass→pass	14,181	8,617	-39%	1	1	0%	2,167	2,049	-5%	0	0	—
case-08 When defining an `@Insert` method in a Room DAO for adding a new product entity to the database, should the function return a Flow or be marked suspend?	pass→pass	8,808	2,802	-68%	1	1	0%	1,317	674	-49%	0	0	—
case-18 When inserting multiple database records using Room `@Insert`, why are write functions declared as `suspend` rather than returning `Flow`?	pass→pass	12,373	6,136	-50%	1	1	0%	2,044	1,241	-39%	0	0	—
case-09 We need strong compile-time type safety for complex key-value application settings stored locally in Android. Which DataStore variant provides type-safe schema definitions via Protocol Buffers?	pass→pass	3,483	3,670	+5%	1	1	0%	582	976	+68%	0	0	—
case-10 I have a DAO method that deletes a parent playlist row and clean-up updates related song mapping tables in Room. Which annotation ensures both operations run within a single database transaction?	pass→pass	5,298	2,667	-50%	1	1	0%	1,014	682	-33%	0	0	—
case-11 When collecting database query results from a Room Flow inside a ViewModel, which CoroutineDispatcher or thread scheduling practice ensures IO work does not execute on the main thread?	fail→pass	10,253	5,274	-49%	1	1	0%	1,821	1,142	-37%	0	0	—
case-12 When defining a Room `@Entity` class in Android, should domain business logic and formatting calculations be placed inside the entity data class?	pass→pass	15,180	6,306	-58%	1	1	0%	2,381	1,394	-41%	0	0	—
case-17 I am writing a Room DAO method that uses `@Embedded` and `@Relation` to load a parent entity with its child entities. What annotation must be placed on the DAO function to prevent partial reads or race conditions during multi-table retrieval?	fail→pass	2,766	2,404	-13%	1	1	0%	450	649	+44%	0	0	—
case-13 We are designing a Room DAO to observe real-time changes to a list of shopping cart items. What reactive return type should the query function use?	pass→pass	8,997	2,796	-69%	1	1	0%	1,699	731	-57%	0	0	—
case-14 Write a Kotlin Hilt `@Module` that provides a DataStore instance using `PreferenceDataStoreFactory`.	pass→pass	8,565	5,587	-35%	1	1	0%	1,845	1,363	-26%	0	0	—
case-15 Where in a clean Android architecture should Room database `@Entity` instances be converted into UI or domain models?	pass→pass	11,115	5,737	-48%	1	1	0%	1,901	1,233	-35%	0	0	—
case-16 We have a legacy codebase using `android.content.SharedPreferences` for user settings. Which modern Jetpack persistence library should we migrate to?	pass→pass	10,060	3,654	-64%	1	1	0%	1,521	799	-47%	0	0	—
case-19 If multiple DataStore instances are created for the same file in an Android app, it throws an IllegalStateException. How do we ensure only one instance exists across the application?	pass→pass	10,139	6,999	-31%	1	1	0%	1,907	1,484	-22%	0	0	—
case-20 We are creating a Retrofit interface for fetching remote weather data over HTTP in Android. How should the API interface and OkHttpClient timeout settings be structured for REST calls?	pass→pass	12,566	8,283	-34%	1	1	0%	2,436	1,850	-24%	0	0	—
case-21 We need to schedule a periodic background sync job that runs every 24 hours using Android Jetpack WorkManager. How should `PeriodicWorkRequestBuilder` and `Constraints` be configured?	pass→pass	11,674	6,148	-47%	1	1	0%	2,056	1,409	-31%	0	0	—
case-22 How do I manage state for a text input field and expandable card animation in Jetpack Compose using `rememberSaveable` and `mutableStateOf`?	pass→pass	11,482	8,304	-28%	1	1	0%	2,391	1,996	-17%	0	0	—

These cases were also screened by the skill’s intent / safety pass.See the Trust review ↗Reproduce this benchmark in Colab ↗

How this skill was measured

DecimalAI ran this skill against gemini-3.6-flash twice over the same eval suite — once with the skill loaded and once without — and compared the two runs case by case. 22 cases were attempted. The headline lift of +9 percentage points is the difference between those two pass rates over the 22 comparable cases.

Model measured: gemini-3.6-flash
Graded by: gemini-3.6-flash
Grading method: judged
Verification: verified
Pass rate without the skill: 90.9%
Pass rate with the skill: 100%
Cases attempted: 22
Cases counted toward lift: 22
Cases that regressed: 0
Skill version measured: v1
Run completed: 8/2/2026, 22:05 UTC

Measured example — same prompt, with vs. without the skill · from the benchmark run · case case-11

Prompt

When collecting database query results from a Room Flow inside a ViewModel, which CoroutineDispatcher or thread scheduling practice ensures IO work does not execute on the main thread?

Without the skill loaded, the model failed this case. With it loaded, the same prompt on the same model passed. This is one improved case from the latest verified run; every case, including any that regressed, is in the table above.

Show both answers

SkillScore blends 4 signals3 of 4 complete

BenchmarkPass rate WITH skill on a verified run100

Live evalPass rate on real evaluated traces100%

AI ratingNeeds ≥10 rated traces

AdoptionBreadth of real use across orgs75

Efficiency · separate axis (at equal correctness)+0% turns-29% tokens

Shown for transparency; not credited unless a verified run shows no correctness regression.

Backed by 3 of 4 signals — each added signal makes the score more robust.

Verified on gemini-3.6-flash · re-tested 56 days ago

Other measured skills in the registry, with their headline benchmark lift.