Tool execution

Architecture

1. Each tool module defines a Context.Tag with Effect schemas.
2. ToolRegistry constructs a managed runtime per module, injecting Bun platform services and path validation.
3. makeAllTools adapts each runtime into the ToolSet consumed by VercelAI.streamChat.

Managed runtimes

src/services/ToolRegistry.ts

// Create a managed runtime with all dependencies
const fileToolsRuntime = ManagedRuntime.make(
  FileToolsLayer.pipe(
    Layer.provide(pathValidationStack),
    Layer.provide(BunContext.layer),
    Layer.orDie, // Convert layer failures to defects
  ),
)

// Adapt runtimes to Vercel AI SDK format
const toolsMap = makeAllTools(
  fileToolsRuntime,
  searchToolsRuntime,
  editToolsRuntime,
  directoryToolsRuntime,
)

return {
  tools: Effect.succeed(toolsMap),
  listToolNames: Effect.succeed(Object.keys(toolsMap).sort()),
}

• ManagedRuntime.make gives each service its own Effect environment.
• Layer.orDie converts checked layer failures into defects so tool execution cannot proceed without prerequisites.

Adapter mapping

src/adapters/index.ts

export const makeAllTools = (
  fileToolsRuntime: ManagedRuntime.ManagedRuntime<typeof FileTools>,
  searchToolsRuntime: ManagedRuntime.ManagedRuntime<typeof SearchTools>,
  editToolsRuntime: ManagedRuntime.ManagedRuntime<typeof EditTools>,
  directoryToolsRuntime: ManagedRuntime.ManagedRuntime<typeof DirectoryTools>,
): ToolSet => ({
  ...makeFileToolsForVercel(fileToolsRuntime),
  ...makeSearchToolsForVercel(searchToolsRuntime),
  ...makeEditToolsForVercel(editToolsRuntime),
  ...makeDirectoryToolsForVercel(directoryToolsRuntime),
})

• Each adapter validates parameters with shared @effect/schema structs wrapped with Schema.standardSchemaV1() for AI SDK v6 compatibility.
• The handler runs inside the managed runtime to access the correct services.
• Results are serialised to JSON automatically for the Vercel AI SDK.

Execution flow

1. VercelAI.streamChat receives a tool call (step.toolCalls).
2. The adapter retrieves the appropriate runtime and executes the Effect.
3. The tool returns structured data; ToolResultPresenter renders it in the CLI.

Tips

• Add new tools by creating a module + layer, adding a runtime in ToolRegistry, and extending makeAllTools.
• Reuse PathValidation in every tool that touches the filesystem to avoid leaving the workspace.
• Keep tool responses small and structured; the assistant summarises diffs and metadata more effectively than raw blobs.

Source

• src/services/ToolRegistry.ts
• src/adapters/index.ts
• src/tools/**/*.ts