LangGraph agent loop

contextweaver running inside a LangGraph agent loop, not as a replacement for one. LangGraph owns control flow; contextweaver owns phase-aware context compilation (route → firewall → answer); tool execution stays outside contextweaver.

TL;DR

What	Where
The script	examples/architectures/langgraph_agent_loop/main.py
Captured output	examples/architectures/langgraph_agent_loop/OUTPUT.md
Local README	examples/architectures/langgraph_agent_loop/README.md

Run it:

python examples/architectures/langgraph_agent_loop/main.py

(Or make architectures / make example. Install the framework path with pip install 'contextweaver[langgraph]'.)

The boundary

Concern	Owner
Control flow (route -> execute -> answer, the per-turn loop)	LangGraph StateGraph
Tool selection bounding (catalog → ChoiceCard shortlist)	contextweaver route phase
Large tool-result firewalling	contextweaver interpret phase
Budget-aware prompt + dependency-chain preservation	contextweaver answer phase
Executing a tool	The app / a tool runtime (here: mocked)

LangGraph is optional

The import is guarded. With LangGraph installed the real StateGraph drives the loop; otherwise an equivalent hand-rolled loop calls the same node functions in the same order. The output is identical apart from one agent loop engine: banner line, so the example runs under a bare pip install contextweaver. See the LangChain + LangGraph guide for the broader integration story.

The scenario

A two-turn ops session; the "model" decision at each node is a deterministic intent map standing in for an LLM holding the rendered ChoiceCards (no API key, no network):

1. "pull the recent error logs for the payments service" → infra.logs_search returns a ~21 KB dump that the firewall compacts to a short summary.
2. "summarize the root cause and draft an incident note" → incident.draft_note; the answer build carries turn 1's firewalled result forward.

Read next

• The comparison page explains why contextweaver complements rather than replaces agent frameworks.
• The catalog showcase is the framework-free version of the same route → firewall → answer flow.