config

Environment variables

The runner reads a small set of env vars at startup. None of them leave your machine — the cloud control plane never sees your Anthropic key.

Required

VariablePurpose
ANTHROPIC_API_KEYBYO Claude API key. The runner reads it once per invocation and forwards on each agent call. Format: sk-ant-…

Optional

VariableDefaultPurpose
PIPEMASON_API_BASEhttps://api.pipemason.comOverride the control-plane URL. Useful for staging.
PIPEMASON_WS_BASEwss://api.pipemason.comOverride the live-update WS base.
PIPEMASON_RUNNER_DIR~/.pipemasonRunner cache + credentials directory.
PIPEMASON_LOG_LEVELinfodebug | info | warn | error.
ANTHROPIC_MODEL_OVERRIDE(none)Force every phase to use this model. Overrides config.yml model tiering. Use with care — defeats cost control.

Where to set them

Most users put ANTHROPIC_API_KEY in their shell profile (~/.zshrc, ~/.bashrc) or a secret manager (1Password CLI, direnv, doppler). The runner inherits whatever's in the env when you invoke it.

# Common pattern: 1Password CLI
export ANTHROPIC_API_KEY="$(op read 'op://Personal/Anthropic API Key/credential')"

# Or just a hardcoded export (dev only)
export ANTHROPIC_API_KEY="sk-ant-…"

Heads-up

Never commit ANTHROPIC_API_KEY to git. The runner has no way to redact it from iterations.log if it leaks into a tool call.
Environment variables · Pipemason Docs