Agent( )

Pattern

PrepareStep: Trim Message History

Demonstrate ToolLoopAgent prepareStep for trimming long message history. Pre-seeded 24-message conversation shows context compression on the first run with per-step trim telemetry.

IntermediateJun 2026View the full pattern on desktop
PrepareStep: Trim Message History preview

Problems solved

  • Trim long message histories before each agent step
  • Keep recent tool results while dropping stale turns
  • Observe prepareStep compression with per-step telemetry
  • Prevent unbounded context growth in ToolLoopAgent loops

Use cases

  • Long-running agents with many tool calls
  • Context-window budget management
  • Debugging what the model sees each step
  • Production agents that must cap history size

AI SDK APIs

ToolLoopAgentprepareStepstepCountIstoolgateway

Tags

aiagentsprepare-stepcontext-windowmessage-trimmingtool-loop-agentai-sdkagent-api

Requirements

Node.js
24+
Memory
512MB
Other
  • OpenAI API key

Environment variables

External services

openai

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