Summon

What it does

When your agent uses it

• Developing applications with the Summon Kotlin Multiplatform UI framework
• Tasks that involve Cross-platform mobile apps
• Tasks that involve State management

Example prompts

• “/summon”

Workflow steps

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

1. 1Use type-safe Modifiers - Never use raw CSS strings; use the Modifier API with type-safe enums
2. 2Don't manipulate DOM directly - Use renderer methods and composable functions
3. 3Add @JsName annotations - Required for public APIs to ensure consistent naming in minified JS
4. 4Don't capture mutable state in lambdas - Use wrapper functions when passing callbacks to renderers
5. 5Use getPlatformRenderer() - For reliable renderer access in JS contexts
6. 6Platform-specific code - Keep in appropriate source sets (commonMain, jvmMain, jsMain, wasmJsMain)

What it can do on your machine

Read from SKILL.md and the folder at commit c66968f. 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 kotlin and bash).

  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

Summon loads about 1.1k tokens when it runs. Until then it costs about 55 tokens; SKILL.md has 249 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~55

When it runs · the whole SKILL.md, loaded when a task matches

~1.1k

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

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 codeyousef/summon at commit c66968f, republished under its Apache-2.0 licence (© codeyousef). 249 words, ~1,100 tokens.

name

summon

description

Use when developing applications with the Summon Kotlin Multiplatform UI framework. Provides patterns, conventions, and guidance for components, state management, modifiers, routing, SSR, and cross-platform code.

@Composable
fun MyComponent(
    value: String,
    onValueChange: (String) -> Unit,
    modifier: Modifier = Modifier()
) {
    val renderer = LocalPlatformRenderer.current
    // Use renderer methods, not direct DOM manipulation
}

// Direct access
val counter = remember { mutableStateOf(0) }
counter.value = counter.value + 1

// Property delegation (preferred)
var counter by remember { mutableStateOf(0) }
counter++

// Destructuring
val (count, setCount) = remember { mutableStateOf(0) }
setCount(count + 1)

Modifier()
    .padding(16.px)
    .backgroundColor(Color.Blue)
    .borderRadius(8.px)
    .display(Display.Flex)
    .alignItems(AlignItems.Center)
    .onClick { /* handler */ }

// Static route
route("/about") { AboutPage() }

// Dynamic parameter
route("/users/[id]") { params ->
    val userId = params.getInt("id")
    UserPage(userId)
}

// Catch-all
route("/docs/[...slug]") { params ->
    DocsPage(params["slug"])
}

@Composable
fun MyComponent() {
    onMount { println("Component mounted") }
    onDispose { println("Component disposed") }

    effectWithDeps(dependency) {
        // Runs when dependency changes
    }
}

val renderer = PlatformRenderer()
val html = renderer.renderComposableRoot(hydrate = true) { MyApp() }

commonMain
    └── webMain (shared JS + WASM code)
            ├── jsMain (browser JS)
            └── wasmJsMain (WebAssembly)

# Build all
./gradlew build

# Run JVM tests (excludes slow tests)
./gradlew :summon-core:jvmTest

# Run JS tests
./gradlew :summon-core:jsNodeTest

# Development run (JS with hot reload)
./gradlew jsBrowserDevelopmentRun

# Publish locally
./gradlew publishLocal

© codeyousef, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

Just SKILL.md in .claude/skills/summon of codeyousef/summon.

Open the folder on GitHubat commit c66968f