google-adk-kotlin-core/com.google.adk.kt.annotations/Tool

Tool

@Target(allowedTargets = [AnnotationTarget.FUNCTION])

annotation class Tool(val name: String = "", val description: String = "", val requireConfirmation: Boolean = false, val isLongRunning: Boolean = false)

Annotates a function to be exposed as an executable tool by the Google ADK Kotlin. KSP will generate a corresponding com.google.adk.kt.tools.FunctionTool wrapper for annotated functions.

The generated wrapper converts the function's return value into a JSON-native Map: data classes, enums, lists, maps, and nested structures are translated at compile time. A function may therefore return a data class directly, unlike a hand-written com.google.adk.kt.tools.BaseTool, whose result must already be JSON-native.

Note: this annotation shares its simple name with com.google.adk.kt.types.Tool, the GenAI tool definition data class. Files that need to reference both should use an import alias.

Retained at runtime so the JVM-only com.google.adk.kt.interop.ReflectiveTools can read it via reflection to build tools from Java methods, which the KSP path cannot process without the Kotlin compiler.

Properties

description

val description: String

An optional explicit description. If not provided, the KDoc summary is used.

isLongRunning

val isLongRunning: Boolean = false

If true, indicates the tool returns a Pending state and resumes later.

name

val name: String

An optional explicit name for the tool. If not provided, the function name is used.

requireConfirmation

val requireConfirmation: Boolean = false

If true, the tool execution requires user confirmation.