Pi (experimental)

Happier can run Pi Coding Agent through the local pi CLI.

Pi is an experimental integration. It works and people use it daily, but its surface is younger than Claude, Codex or OpenCode and is more likely to change. What it supports today is in Agent capabilities.

Install Pi

Happier can install it for you:

happier install provider pi
pi --version

Or install manually:

npm install -g @earendil-works/pi-coding-agent
pi --version

Start Pi with Happier

happier pi

Permissions

Use the shared permission vocabulary when starting Pi:

happier pi --permission-mode read_only
happier pi --permission-mode auto

Read-only limits Pi to Happier's read-tool allowlist. Auto, Default, and YOLO do not pass Pi's --tools option, so Pi keeps its full native catalog, including the platform shell and installed extension/custom tools such as subagents. Auto is not a workspace-confinement guarantee. Older spellings such as safe-yolo and workspace_write remain accepted for compatibility.

For the cross-provider vocabulary and aliases, see Permissions.

Local authentication in Happier

Pi does not currently expose a native interactive login flow through Happier provider settings.

Instead, Happier shows the machine-local auth state for Pi in:

Settings → AI & Agents → AI backends → Pi

Today that status is based on supported environment-backed credentials on the selected machine.

For the shared user guide, see Provider authentication.

Authentication (connected services)

Pi can reuse connected services profiles when spawned by Happier:

openai-codex (subscription OAuth)
openai (API key)
claude-subscription (OAuth or setup-token) for Claude subscription auth
anthropic for Anthropic API key auth (ANTHROPIC_API_KEY)

Happier materializes compatible connected services into Pi's isolated PI_CODING_AGENT_DIR/auth.json before launch. Claude subscription OAuth profiles are written as Pi OAuth credentials; setup-token and API-key profiles are written as Pi API-key credentials.

If multiple compatible profiles exist, Happier will let you pick one when starting a new session.

Policy note: Claude subscription OAuth credentials are intended for ordinary Claude subscription use in native Anthropic applications. Developers building third-party products should use Anthropic API keys or supported cloud providers unless their policy/legal review permits this Pi integration path.

See: Connected services

Troubleshooting

If Pi is not detected:

Verify pi --version works.
Restart Happier.
Set HAPPIER_PI_PATH if your binary is not in PATH.

Pi's vendor-managed installer can put its launcher at ~/.pi/agent/bin/pi, or under PI_CODING_AGENT_DIR/bin/pi when that directory is configured. An already running daemon may retain a PATH from before installation. Point HAPPIER_PI_PATH at the launcher and restart the daemon if terminal launches work but daemon launches fail.

Current development builds also discover these locations when PATH has no Pi executable. If launch resolution still fails, they report provider_cli_not_found with installation or override guidance. An invalid HAPPIER_PI_PATH must be corrected or unset; it does not fall back to another installation.

Agent capabilities — what this agent supports, generated from the manifest.
Choosing an agent
Model and engine selection
Agent authentication