Call a Golem tool from Scala

Call an existing tool through a generated client

Load golem-generating-tool-clients to select a built-in release or MCP import and add it to the Scala component’s dependencies.tools. Configure its runtime binding separately. golem build automatically generates the client without an explicit bridge selection. Include the generated sources in the consumer build. In the standard sbt template, add this setting to the consumer project’s existing .settings(...) block. LocalRootProject resolves the application root rather than the component directory:

Compile / unmanagedSourceDirectories += (LocalRootProject / baseDirectory).value /
  "golem-temp/bridge-sdk/scala/internal/bash-tool-guest-client/src/main/scala"

Call the built-in bash release 0.2.1 inside an agent method:

import golem.bridge.client.bash.BashClient
 
val pending = BashClient().run("printf 'hello\\n'", "", golem.UInt(600L))

pending is a Future of an Either: handle the tool failure or inspect the result’s stdout, stderr, and exit code. Bash returns those strings in its result, not stream handles. For streaming commands, use the invocation’s collect() to drain both channels concurrently and check each outcome.

Call from a definition owned by the application

@toolDefinition generates <Tool>Client. Construct it with the generated factory and call the typed asynchronous methods:

import golem.tool.ToolError
import scala.concurrent.Future
 
val client: EchoClient = EchoClient()
val result: Future[Either[ToolError[Nothing], String]] =
  client.echo("hello")

Use the exact generated signature: a command with declared errors uses the error type declared by the tool method instead of Nothing. Commands without stdout or stderr, including stdin-only commands, return Future[Either[ToolError[E], A]]; stdin is a ToolInputStream parameter. A command with either output returns Either[ToolError[E], ToolInvocation[E, A]], whose invocation exposes the result and independent stdout/stderr streams. Drain both outputs concurrently. Handle ToolError.Tool separately from protocol failures. Never edit generated clients.