ADR 001: Defer LangGraph Runtime

Status: Superseded / deferred Date: 2026-05-12

Decision

Humanwork will not ship a LangGraph runtime or /graph/invoke rollback path in the current agent deployment. The active runtime is the Hermes-backed FastAPI service exposed through /chat, /chat/stream, and /v1/chat.

Rationale

• The team is standardizing on Hermes Agent rather than maintaining a second agent orchestration framework.
• The LangGraph path was not the deployed Railway runtime and created confusion about what was actually supported.
• Removing the rollback keeps dependency, test, and deployment scope focused on the code path we intend to operate.

Consequences

• agent/graph.py, agent/legacy_graph.py, and /graph/invoke are removed.
• LangGraph and LangChain dependencies are removed from the agent runtime.
• Future agent orchestration work should be implemented through Hermes Agent or a new ADR that explicitly reopens this decision.