Architecture
7 min readUpdated: October 2026

Context Compaction for LLMs: How to Prevent Agent Context Window Overflow

In autonomous coding loops, reading large source files and executing terminal commands rapidly consumes tens of thousands of context window tokens. Without intelligent compaction, agents crash or cost hundreds of dollars per session. Smoke Monkey Harness features automatic token budget compaction.

Technical Review: Smoke Monkey Core Architecture Team
Tested on Node.js 18+ & BunTypeScript 5.x
Quick Answer & Executive Definition

Context Compaction for LLMs: How to Prevent Agent Context Window Overflow: In autonomous coding loops, reading large source files and executing terminal commands rapidly consumes tens of thousands of context window tokens. Without intelligent compaction, agents crash or cost hundreds of dollars per session. Smoke Monkey Harness features automatic token budget compaction. Designed as a zero-dependency, open-source TypeScript architecture under the MIT License with native Model Context Protocol (MCP) support and deterministic phase state machines.

Key Architectural Takeaways

Why Simple Truncation Fails

Naive memory management strategies simply chop off the earliest messages in the conversation. When this happens, the agent forgets initial user requirements, project constraints, and earlier findings, leading to regressions. Smoke Monkey compacts turns into structured summary blocks.

Google Search Questions & Answers

Frequently Asked Questions

Q:Can I customize the compaction prompt or token threshold?

Yes! You can configure compaction thresholds and strategy functions in `createAgent()` options.

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Build with Smoke Monkey Harness

Zero dependencies. 24 built-in tools. Human-in-the-loop safety. 100% open source under the MIT License.

npm install smoke-monkey-harness