Installables

Some Happier features depend on machine-local tools being present on the connected machine.

Happier calls these Installables.

Today, the main user-facing installables are:

• Codex ACP — used when you explicitly run Codex in ACP mode instead of the default App Server path

Why Installables exist

Some features need more than the main Happier app and daemon. For example, Codex ACP needs a machine-local codex-acp binary when you explicitly run Codex in ACP mode rather than the default App Server path.

Without Installables management, this usually turns into:

• manual setup on every machine
• version drift between machines
• slower cold starts when a tool has to be fetched on demand

Installables gives you one place to see and control those tools per machine.

Where to manage them

Open:

• Machine details → Installables

This screen shows the installables Happier knows how to manage for that specific machine.

For each installable, you can see:

• whether it is installed
• the installed version
• whether an update is available
• the latest known version (when Happier checks it)
• the current auto-install and auto-update policy

Auto-install when needed

Each installable has an Auto-install when needed setting.

When this is on, Happier can install the tool in the background when you use a feature that depends on it.

Example:

• you start a new Codex session with the ACP backend
• Happier sees that Codex ACP is relevant for that session
• if Codex ACP is missing and auto-install is enabled, Happier starts a background install on that machine

This is designed to improve the next relevant session without blocking the current one.

Auto-update modes

Each installable also has an Auto-update policy:

• Off: never update automatically
• Notify: show that an update is available, but do not upgrade automatically
• Auto: upgrade automatically in the background when Happier checks and sees that a newer version is available

Default behavior for Happier-managed installables is:

• Auto-install when needed: on
• Auto-update: auto

What happens for Codex-related installables

App Server default path

Normal Codex sessions and resume on the default App Server path do not depend on the Codex ACP installable.

That means:

• you do not need Codex ACP installed just to use default Codex App Server sessions
• you do not need any extra Codex installable for normal App Server resume

Codex ACP mode

Codex ACP still matters only when you explicitly choose the ACP backend.

New Codex sessions

If you start a new Codex session and select the ACP backend:

• Happier tries to keep the session usable immediately
• if Codex ACP is already installed, it uses the installed binary
• if Codex ACP is missing, Happier can still fall back to the existing fresh-session path while it installs Codex ACP in the background for future sessions

This means the first ACP-related session on a machine may still be slower than later ones.

Resuming Codex sessions in ACP mode

Codex resume is stricter:

• resume requires Codex ACP
• if ACP is unavailable, Happier does not silently replace resume with a fresh session

If resume is important on a machine, leave Codex ACP installed and let Happier keep it updated.

Plain MCP note

If you switch Codex to plain mcp, Happier can still start fresh Codex sessions there, but vendor resume is not available on that path in current builds.

Scope and expectations

Installables are managed per machine.

That means:

• one machine can have Codex ACP installed while another does not
• policies are stored per machine
• updates happen on the machine that owns the installable

This is especially useful if you use:

• a laptop and a desktop
• multiple remote devboxes
• separate personal and work machines

What Installables do not change

Installables management does not force you to use a managed copy when you already have your own tool installed.

In general, Happier still prefers a working user/system install by default when the provider resolution logic supports that.

Installables mainly gives Happier a reliable managed path so that:

• required tools can be present without manual setup
• supported features keep working on fresh machines
• background installs and updates reduce cold-start surprises