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RunLedger for langchain

RunLedger is framework-agnostic; wrap LangChain tool usage to speak the RunLedger protocol.

integration langchain tools Updated 2026-01-26

Direct Answer

Run your LangChain agent as the subprocess and emit RunLedger tool_call events whenever the chain wants a tool; wait for tool_result replies.

Quick Decision

Use RunLedger when Consider alternatives when
You can add a thin adapter around LangChain. You cannot modify or wrap the agent.
You need deterministic replay in CI. You only need offline unit tests.
You want hard CI gates. You only need qualitative scoring.

Integration pattern

  • Read task_start from stdin and build the chain input.
  • On tool selection, emit tool_call and wait for tool_result.
  • Return final_output as JSON to stdout.

Pseudo loop

text 
for line in stdin:
          if type == task_start: run chain
          if chain requests tool: emit tool_call
          await tool_result
        emit final_output

Tradeoffs

  • Requires an adapter layer around LangChain execution.
  • Strict protocol limits where logs can be written.
  • Tool order constraints may require extra wiring.

When NOT to use RunLedger

Skip this integration if you cannot intercept tool calls or control the agent process.

Next steps

Read the Golden Path Back to Answer Hub
Last updated: 2026-01-26