cmp-dev-client

A desktop development setup for Compose Multiplatform apps, which share user-interface code across platforms. It opens the shared interface in a clickable desktop window and updates it after code changes.

In plain words
What is it for?
It helps developers preview screens, navigation, themes, view models, and dependency-injection wiring on desktop, with optional automatic hot reload.
Why use it?
It shortens the edit-and-check cycle by avoiding repeated emulator or simulator launches while building the interface.

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/kvdm-co-pilot/create-cmp/cmp-dev-client
Any agent
npx skills add kvdm-co-pilot/create-cmp --skill cmp-dev-client
Clone the repo
git clone --depth 1 https://github.com/kvdm-co-pilot/create-cmp

Made for: Claude Code, Codex.

Per session 139 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,256 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 $0.00139 $0.01256
Opus 5 $0.00069 $0.00628
Sonnet 5 $0.00028 $0.00251
Haiku 4.5 $0.00014 $0.00126

Measured yesterday against content hash 69ce6fca5179, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

cmp-dev-client 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 yesterday.

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/cmp-dev-client/SKILL.md · 96 lines

How it starts

The opening of the file, as written. The whole thing — 96 lines — stays where its author put it; the contents beside it link to each section on GitHub.

cmp-dev-client — the desktop dev loop for a stamped CMP app

Every app stamped by create-cmp (unless --no-dev-client) ships a pre-wired jvm("desktop") target inside composeApp: the whole commonMain UI — screens, ViewModels, navigation, theme, Koin DI — in a live, clickable, phone-sized JVM window, with Compose Hot Reload attached. This is the daily-driver loop; the Android emulator / iOS simulator are for platform verification, not for iterating on UI.

1. The run loop

From the generated project root:

# Hot reload + auto-reload on save (recommended):
./gradlew :composeApp:hotRunDesktop --auto

# Hot reload, explicit mode (trigger with `./gradlew reload` or the IDE's Reload UI button):
./gradlew :composeApp:hotRunDesktop

# Plain run — no hot reload, no JetBrains Runtime needed, any JDK 17+:
./gradlew :composeApp:run

Loop: keep the window open → edit a composable in commonMain → save → the window updates in place. No reinstall, no restart, state largely preserved.

Notes you should relay when relevant:

  • The task is hotRunDesktop because the target is named desktop (hotRunJvm is the default-name variant you'll see in JetBrains docs).
  • Hot reload runs the app on the JetBrains Runtime. The scaffold pre-wires the foojay-resolver-convention settings plugin, so Gradle auto-downloads a JBR on first hotRunDesktop if none is installed — a one-time download; don't let the user think it hangs.
  • Structural changes (new expect/actual, Gradle edits, new modules) need a task restart; in-function/UI edits hot-swap.
  • The window is phone-sized (411×891 dp, titled <AppName> dev-client) so what the user sees approximates the device layout.

2. What's faked on desktop (and how to extend it)

Desktop platform seams live in composeApp/src/desktopMain/kotlin/<package>/:

Seam Desktop implementation
NetworkMonitor Always-online stub
Room Real Room (BundledSQLiteDriver) writing to the OS temp dir — disposable cache
Firebase Never initialized — zero Firebase code, config, or network on desktop
Example ItemRepository The same in-memory ItemRepositoryImpl all platforms bind

Read the full file on GitHub · 96 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.

  1. yesterday First seen · 96 lines · 139 tokens per session scan A 69ce6fca5179

Subscribe to this mod's changes

cmp-dev-client is a skill published in the GitHub repository kvdm-co-pilot/create-cmp (0 stars, last pushed 3d ago), licensed MIT. It adds 139 tokens to every session and 1,256 once invoked, about $0.0007 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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