LangGraph example: silent loops

A two-node LangGraph (generator / reviewer) where the reviewer never approves and work loops back to the generator forever. Tokens burn quietly.

5 minutes. Clone, install, run.

Before (without AgentSonar)

pip install langgraph
cd before && python pipeline.py
# silent burn. No alerts. ~\$14.50 in mocked tokens.

After (with AgentSonar — detect)

pip install agentsonar[langgraph]
cd after && python detect.py
# alert fires at rotation 5, escalates at 15. report.html on disk.

After + Prevent Mode (auto-stop)

cd after && python prevent.py
# graph.invoke() halts at rotation 10. ~\$4.83 mocked cost. Saved \$9.67.

The only change you made

See what-changed.md for the literal diff.

Cost numbers

Mocked, based on Claude Sonnet 4.6 pricing as of 2026-05-09 ($3 / 1M input tokens, $15 / 1M output tokens). Source: anthropic.com/pricing.