Configuration

pier setup writes ~/.config/pier/config.toml. Change any setting later from the TUI settings page. Run pier and press s.

The settings page groups session, AWS, and GCP fields, validates values before saving them, and keeps setup- and bake-managed values read-only. Changes apply to new sessions; existing sessions keep the cloud and machine they were built with.

driver = "aws-ec2"
idle_timeout = "30m"      # detached and quiet this long -> park ("never" disables)
unattended_cap = "8h"     # parks even while busy ("never" disables)

[aws]
profile = "default"
region = "eu-central-1"
instance_type = "t4g.medium"   # machine for new sessions
disk_gib = 40
subnet = ""                    # optional: orgs without a default VPC
direct = true                  # ssh straight to the VM. false forces the SSM tunnel

[gcp]                          # when driver = "gcp-gce"
project = "my-project"
zone = "europe-west3-a"
machine_type = "e2-medium"
disk_gib = 40

Keys

Key	Default	Meaning
`driver`	`aws-ec2`	the cloud driver: `aws-ec2` or `gcp-gce`
`idle_timeout`	`30m`	detached and quiet this long parks the VM, `never` disables
`unattended_cap`	`8h`	parks even while busy, so a looping agent can’t burn compute for days
`aws.profile`		the AWS CLI profile pier calls with
`aws.region`		where sessions run
`aws.instance_type`	`t4g.medium`	machine for new sessions
`aws.disk_gib`	`40`	EBS disk size per session
`aws.subnet`		optional, for orgs without a default VPC
`aws.direct`	`true`	ssh straight to the instance’s public IP, port 22 open to your IP only, SSM tunnel as fallback. `false` forces the tunnel
`gcp.project`		the GCP project sessions run in
`gcp.zone`	`europe-west3-a`	where sessions run
`gcp.machine_type`	`e2-medium`	machine for new sessions
`gcp.disk_gib`	`40`	boot disk size per session

Per-session overrides beat the config: --idle and --cap at create time.

Managed sections

Three sections are managed by pier, not by hand:

[aws.baked_amis] and [gcp.baked_images] map repo basenames to baked images. pier bake writes them, pier teardown sweeps the images.
[secrets] holds the manifest of files and dirs under $HOME copied one-way into each session at create, plus an optional claude_oauth_token from claude setup-token (the macOS Keychain escape hatch, injected as CLAUDE_CODE_OAUTH_TOKEN in sessions).