agent/.core/reference/docs/subsystems.md

title	description
Subsystems	Built-in accessors for app metadata, embedded data, filesystem, transport handles, i18n, and CLI.

Subsystems

Core gives you a set of built-in subsystems so small applications do not need extra plumbing before they can do useful work.

Accessor Map

Accessor	Purpose
App()	Application identity and external runtime
Data()	Named embedded filesystem mounts
Drive()	Named transport handles
Fs()	Local filesystem access
I18n()	Locale collection and translation delegation
Cli()	Command-line surface over the command tree

App

App stores process identity and optional GUI runtime state.

app := c.App()
app.Name = "agent-workbench"
app.Version = "0.25.0"
app.Description = "workspace runner"
app.Runtime = myRuntime

Find resolves an executable on PATH and returns an *App.

r := core.Find("go", "Go toolchain")

Data

Data mounts named embedded filesystems and makes them addressable through paths like mount-name/path/to/file.

c.Data().New(core.Options{
	{Key: "name", Value: "app"},
	{Key: "source", Value: appFS},
	{Key: "path", Value: "templates"},
})

Read content:

text := c.Data().ReadString("app/agent.md")
bytes := c.Data().ReadFile("app/agent.md")
list := c.Data().List("app")
names := c.Data().ListNames("app")

Extract a mounted directory:

r := c.Data().Extract("app/workspace", "/tmp/workspace", nil)

Path Rule

The first path segment is always the mount name.

Drive

Drive is a registry for named transport handles.

c.Drive().New(core.Options{
	{Key: "name", Value: "api"},
	{Key: "transport", Value: "https://api.lthn.ai"},
})

c.Drive().New(core.Options{
	{Key: "name", Value: "mcp"},
	{Key: "transport", Value: "mcp://mcp.lthn.sh"},
})

Read them back:

handle := c.Drive().Get("api")
hasMCP := c.Drive().Has("mcp")
names := c.Drive().Names()

Fs

Fs wraps local filesystem operations with a consistent Result shape.

c.Fs().Write("/tmp/core-go/example.txt", "hello")
r := c.Fs().Read("/tmp/core-go/example.txt")

Other helpers:

c.Fs().EnsureDir("/tmp/core-go/cache")
c.Fs().List("/tmp/core-go")
c.Fs().Stat("/tmp/core-go/example.txt")
c.Fs().Rename("/tmp/core-go/example.txt", "/tmp/core-go/example-2.txt")
c.Fs().Delete("/tmp/core-go/example-2.txt")

Important Details

• the default Core starts with Fs{root:"/"}
• relative paths resolve from the current working directory
• Delete and DeleteAll refuse to remove / and $HOME

I18n

I18n collects locale mounts and forwards translation work to a translator implementation when one is registered.

c.I18n().SetLanguage("en-GB")

Without a translator, Translate returns the message key itself:

r := c.I18n().Translate("cmd.deploy.description")

With a translator:

c.I18n().SetTranslator(myTranslator)

Then:

langs := c.I18n().AvailableLanguages()
current := c.I18n().Language()

Cli

Cli exposes the command registry through a terminal-facing API.

c.Cli().SetBanner(func(_ *core.Cli) string {
	return "Agent Workbench"
})

r := c.Cli().Run("workspace", "create", "--name=alpha")

Use commands.md for the full command and flag model.