What is developing-with-compose-previews?

A guide to using Jetpack Compose `@Preview` functions as the main feedback loop for building UI. It explains how to keep previews independent from view models, dependency injection, network images, and other runtime services.

Use it to structure composables for previews, show loading, empty, error, long-text, and right-to-left states, or fix previews that crash or fail to load images.

It helps previews render reliably and show useful states without building and navigating through the whole app. This makes it easier to catch UI problems while editing code.

developing-with-compose-previews

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/skydoves/android-testing-skills/developing-with-compose-previews

Any agent

npx skills add skydoves/android-testing-skills --skill developing-with-compose-previews

Clone the repo

git clone --depth 1 https://github.com/skydoves/android-testing-skills

Made for: Claude Code, Codex.

Per session 216 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 3,602 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.

Model	Per session	Once invoked
Fable 5	$0.00216	$0.03602
Opus 5	$0.00108	$0.01801
Sonnet 5	$0.00043	$0.00720
Haiku 4.5	$0.00022	$0.00360

Measured 3d ago against content hash 1dbbb43d7d17, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

developing-with-compose-previews 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.

compose/preview/developing-with-compose-previews/SKILL.md · 226 lines

How it starts

The opening of the file, as written. The whole thing — 226 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Developing With Compose Previews — Preview-Driven Development

@Preview is the cheapest verification loop in Compose: edit, see the render in ~1 s, no build/install/navigate cycle. It only pays off if composables are structured so previews stay alive — hoisted state, no ViewModel in the signature, realistic sample data. This skill encodes that structure and the anti-patterns that cause teams to abandon previews. For taking those previews as on-device screenshots in CI, see ../capturing-preview-screenshots-in-ci/SKILL.md.

When to use this skill

A @Preview "fails to render" or crashes because the composable takes a ViewModel, repository, or Context-bound dependency.
The user wants to see loading / empty / error / overflow-text / RTL states without running the app — @PreviewParameter territory.
A composable loads images with Coil/Glide and the preview shows nothing — needs LocalInspectionMode.
The user asks "how should I structure Compose previews so they don't keep breaking" or mentions "preview-driven development".
Previews exist but drift out of date / show the "out of date" banner constantly and the team is about to delete them.

When NOT to use this skill

The user wants to capture previews as screenshots on a device or in CI (HotSwan captureAllPreviews, GitHub Pages catalog) — use ../capturing-preview-screenshots-in-ci/SKILL.md.
The user wants pixel-diff golden-image regression tests (Paparazzi / Roborazzi) — that is a different tool; see ../capturing-preview-screenshots-in-ci/SKILL.md for where it fits relative to device rendering.
The user is writing behavioral UI tests (ComposeTestRule, finders, assertions) — start at ../../setup/configuring-test-dependencies/SKILL.md and ../../finders/finding-nodes-by-tag-text-content/SKILL.md.

Prerequisites

androidx.compose.ui:ui-tooling-preview on the main classpath (provides @Preview, @PreviewParameter, PreviewParameterProvider; see compose/ui/ui-tooling-preview/), plus debugImplementation("androidx.compose.ui:ui-tooling") so Android Studio can render.
LocalInspectionMode ships in androidx.compose.ui:ui (compose/ui/ui/.../platform/InspectionMode.kt — staticCompositionLocalOf { false }), no extra dependency.
A Compose-enabled module (the org.jetbrains.kotlin.plugin.compose plugin or buildFeatures.compose = true).

Read the full file on GitHub · 226 lines

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.

3d ago First seen · 226 lines · 216 tokens per session scan A 1dbbb43d7d17

Subscribe to this mod's changes

developing-with-compose-previews is a skill published in the GitHub repository skydoves/android-testing-skills (313 stars, last pushed 3mo ago), licensed Apache-2.0. It adds 216 tokens to every session and 3,602 once invoked, about $0.0011 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 2026-08-30.

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