Most LangGraph examples stop at “here’s a graph in a notebook.” This MIT-licensed template shared on r/LangChain ships the boring production parts — and 800+ tests to prove they work.
- 13 domain packs — research, meeting prep, support triage, contract review, and 9 more, behind a versioned registry with canary traffic weights and sticky sessions
- Per-run USD budgets — cost tracked per run; requests exceeding
PACK_DEFAULT_BUDGET_USDreturn HTTP 402, killing runaway agent loops before they drain your wallet - Mock mode —
LLM_PROVIDER=mockgives deterministic zero-cost responses on every endpoint, so the full test suite and CI run without an API key - Plugin system — third-party packs load via entry-point discovery, opt-in and allowlisted, with schema validation
- Auto-generated routes — typed
POST /packs/{id}/run+ SSE streaming endpoints generated from each pack’s schema
The template targets a gap most LangGraph tutorials skip: deployment infrastructure. Graph construction and state management are well-documented. Budget enforcement, canary routing, and test coverage are not. The pack registry treats each workflow as a versioned, independently routable unit — closer to how platform teams ship services than how most people prototype agents.
NOTE
The HTTP 402 response on budget overrun is an uncommon choice. Most agent frameworks log cost after the fact. Returning a payment-required status mid-run gives the client a structured signal to raise the budget or abort — rather than discovering the damage in a billing dashboard.
MIT-licensed, actively seeking issues and PRs. The author’s stated goal is making it useful for people shipping agents, not maintaining a personal fork.