PierPier
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Configuration

Pier loads configuration from a single JSON file in your Pier home directory, with optional environment variable and CLI overrides.

Where config lives

By default, Pier uses ~/.pier as its home directory. The configuration file is:

~/.pier/config.json

You can change the home directory by setting PIER_HOME or passing --home to pier daemon start.

Precedence

Pier merges configuration in this order:

  1. Defaults
  2. config.json
  3. Environment variables
  4. CLI flags

Lists append across sources (for example, hostnames and cors.allowedOrigins).

Example

Minimal example that configures listening address, hostnames, and MCP:

{
  "$schema": "https://usepier.sh/schemas/pier.config.v1.json",
  "version": 1,
  "daemon": {
    "listen": "127.0.0.1:6767",
    "hostnames": ["localhost", ".localhost"],
    "mcp": { "enabled": true }
  }
}

daemon.hostnames is the primary field. The old daemon.allowedHosts name still works as a deprecated alias for backward compatibility.

Agent providers

Agent providers, both the first-class ones Pier ships with and custom entries you add under agents.providers, are documented on their own page.

See Providers for the mental model and Supported providers for the full list of agents Pier can launch. For pointing Claude at Anthropic-compatible endpoints (Z.AI, Alibaba/Qwen), multiple profiles, custom binaries, ACP agents, and the additionalModels merge behavior, see Custom providers. The full field reference lives on GitHub at docs/custom-providers.md.

Worktrees

New worktrees are created under $PIER_HOME/worktrees by default. To place new worktrees somewhere else, set worktrees.root:

{
  "worktrees": {
    "root": "/mnt/fast/pier-worktrees"
  }
}

Relative paths are resolved against PIER_HOME. Existing worktrees remain where they are; changing this setting only changes where Pier creates and discovers Pier-managed worktrees going forward.

Voice

Voice is configured through features.dictation and features.voiceMode, with provider credentials under providers.

For voice philosophy, architecture, and complete local/OpenAI setup examples, see Voice docs.

Logging

Daemon logging uses separate console and file sinks by default:

  • Console: info and above
  • File ($PIER_HOME/daemon.log): trace and above
  • File rotation: 10m max file size, 2 retained files total (active + 1 rotated)
{
  "log": {
    "console": {
      "level": "info",
      "format": "pretty"
    },
    "file": {
      "level": "trace",
      "path": "daemon.log",
      "rotate": {
        "maxSize": "10m",
        "maxFiles": 2
      }
    }
  }
}

Legacy fields log.level and log.format are still supported and map to the new destination settings.

Password authentication

You can require a password to connect to the daemon. When set, all HTTP and WebSocket clients must authenticate. Only the /api/health liveness endpoint is exempt, so that process supervisors and load balancers can probe without credentials.

The easiest way to set a password is with the CLI:

pier daemon set-password

This prompts for a password, writes the bcrypt hash to config.json, and tells you to restart the daemon.

Alternatively, set the PIER_PASSWORD environment variable (plaintext, hashed automatically at startup):

PIER_PASSWORD=my-secret pier daemon start

Or write the hash directly in config.json:

{
  "daemon": {
    "auth": {
      "password": "$2b$12$..."
    }
  }
}

After setting a password, restart the daemon for the change to take effect.

Connecting with a password

The CLI picks up a password from, in order:

  1. The password query parameter on a tcp:// host URI:

    pier --host "tcp://192.168.1.10:6767?password=my-secret" ls

  2. The PIER_PASSWORD environment variable, used as a fallback when the host carries no embedded password (works for localhost:6767, bare host:port, or tcp:// hosts without a password= query):

    PIER_PASSWORD=my-secret pier ls
PIER_PASSWORD=my-secret pier --host 192.168.1.10:6767 ls

A password= in the URI always wins over the env var, so you can keep PIER_PASSWORD set globally and still target a different daemon by spelling its password into the URI.

In the mobile app, enter the password in the direct connection setup screen.

Common env vars

  • PIER_HOME, set Pier home directory
  • PIER_PASSWORD, on the daemon, the password to require (plaintext, hashed at startup); on the CLI, the password used to connect when the host URI doesn't include one
  • PIER_LISTEN, override daemon.listen
  • PIER_HOSTNAMES, override/extend daemon.hostnames
  • PIER_ALLOWED_HOSTS, deprecated alias for PIER_HOSTNAMES
  • PIER_LOG_CONSOLE_LEVEL, override log.console.level
  • PIER_LOG_FILE_LEVEL, override log.file.level
  • PIER_LOG_FILE_PATH, override log.file.path
  • PIER_LOG_FILE_ROTATE_SIZE, override log.file.rotate.maxSize
  • PIER_LOG_FILE_ROTATE_COUNT, override log.file.rotate.maxFiles
  • PIER_LOG, PIER_LOG_FORMAT, legacy log overrides (still supported)
  • OPENAI_KEY, OpenAI speech STT/TTS credential from the Pier Doppler account
  • OPENAI_API_KEY, OpenAI-compatible agent provider key for providers such as Codex
  • PIER_VOICE_LLM_PROVIDER, override voice LLM provider (claude, codex, opencode)
  • PIER_DICTATION_STT_PROVIDER, PIER_VOICE_STT_PROVIDER, PIER_VOICE_TTS_PROVIDER, override voice provider selection (local or openai)
  • PIER_LOCAL_MODELS_DIR, control local model directory
  • PIER_DICTATION_LOCAL_STT_MODEL, override local dictation STT model
  • PIER_VOICE_LOCAL_STT_MODEL, PIER_VOICE_LOCAL_TTS_MODEL, override local voice STT/TTS models
  • PIER_DICTATION_LANGUAGE, PIER_VOICE_LANGUAGE, override dictation and voice STT language
  • PIER_VOICE_LOCAL_TTS_SPEAKER_ID, PIER_VOICE_LOCAL_TTS_SPEED, optional local voice TTS tuning

Schema

For editor autocomplete/validation, set $schema to:

https://usepier.sh/schemas/pier.config.v1.json