Package Stack

Feynman is built on the Pi runtime and uses curated Pi packages for its capabilities. Packages are managed through feynman packages commands and configured in ~/.feynman/agent/settings.json.

Feynman also ships a local research extension that registers project-specific tools such as AlphaXiv wrappers, Feynman commands, and read-only Hugging Face Hub inspection. Those extension tools are bundled with Feynman itself rather than installed as separate Pi packages. Pi runtime observability is provided by the bundled pi-otel package, pointed at PostHog AI Observability through trace-specific OTLP variables, and configured for metadata-only spans by default. CLI spans use PostHog distributed tracing and are queryable from posthog.trace_spans; Pi LLM/tool spans appear in AI Observability and as $ai_* events.

This page follows Pi’s upstream docs for packages, extensions, and skills. Feynman adds its own package presets and bundled research extension on top of that model.

Core packages

These are installed by default with every Feynman installation. They provide the foundation for research workflows while still letting Pi own the underlying runtime, RPC transport, provider model, and package loader.

Package	Purpose
@companion-ai/alpha-hub	Direct alphaXiv tools for paper and author workflows
pi-subagents	Parallel agent spawning for literature gathering and task decomposition. Powers the multi-agent workflows
pi-btw	Side conversations while the main research agent is busy, including /btw follow-ups and handoff back into the main thread
pi-docparser	Parse PDFs, Office documents, spreadsheets, and images through bounded, isolated native workers
pi-web-access	Multi-provider web search, raw and page-grounded retrieval, stored-page passage lookup, GitHub access, PDFs, and direct image/media retrieval
pi-otel	OpenTelemetry spans for Pi sessions, model calls, turns, and tool usage, exported without prompt or tool payload content

These packages are updated together when you run feynman update. You do not need to install them individually.

Bundled research extension

Tool group	Purpose
AlphaXiv tools	Search papers, fetch paper reports, ask paper questions, read linked code, and manage annotations
Hugging Face Hub tools	Inspect dataset metadata, features, splits, access status, and small files from model, dataset, and Space repos
Feynman commands	/help, /outputs, /init, /feynman-model, /service-tier, /thinking, and discovery helpers

Optional packages

Install on demand with feynman packages install <preset>. These extend Feynman with capabilities that not every user needs.

Package	Preset	Purpose
@samfp/pi-memory	memory	Pi-managed preference and correction memory for research-session continuity
@luxusai/pi-hindsight	hindsight	Hindsight-backed research-continuity memory. Requires a Hindsight server or Hindsight Cloud account
@kaiserlich-dev/pi-session-search	session-search	Indexed recall for prior research-session transcripts. Available through Node.js 22.x while its sqlite dependency is native-bound

Installing and managing packages

List supported optional research packages and their install status:

feynman packages list

Install a specific optional preset:

feynman packages install session-search

Updating packages

Reconcile all installed packages with their configured versions:

feynman update

Update a specific package:

feynman update pi-subagents

Running feynman update without arguments updates unpinned packages to their current registry versions and repairs stale exact-pinned core packages to the versions shipped by Feynman. Semver ranges and registry tags remain unpinned selectors and are preserved during installation. Pass a specific package name to reconcile just that one. Updates are safe and preserve your configuration.

This command updates Pi packages inside Feynman’s environment. To upgrade the standalone Feynman app itself, rerun the installer from the Installation guide.