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Engineering

Context Window Optimization: Beyond Naive Truncation

Why truncating context is costing you quality. Learn how semantic compression preserves meaning while dramatically reducing token usage.

James Hollingsworth(Contributor)Published 6 min~270 words

The Truncation Problem

Most developers handle large contexts the same way: truncate to the last N tokens. This is fast and simple, but it throws away information indiscriminately.

What you lose with truncation:

  • Early context that establishes the problem domain
  • Function definitions referenced later in the code
  • Important constraints mentioned at the beginning of a document
  • A Better Approach: Semantic Compression

    Instead of cutting from one end, semantic compression analyzes the entire document and keeps the most important parts regardless of position.

    How It Works

  • Chunking: Split the document into semantic units (paragraphs, functions, sections)
  • Embedding: Generate vector representations of each chunk
  • Graph construction: Build a graph where edges represent semantic similarity
  • Importance scoring: Use PageRank to identify the most structurally important chunks
  • Skeleton extraction: Keep the top-ranked chunks, maintaining document order
  • The Key Insight

    Documents have structure. A well-written technical document has:

  • Scaffolding: the logical structure that everything hangs on
  • Detail: examples, elaboration, edge cases
  • Redundancy: concepts restated in different ways
  • Compression removes detail and redundancy while preserving scaffolding. The LLM still understands the context because the skeleton carries the meaning.

    Three Research Papers Behind Our Engine

    We've implemented three compression techniques:

  • STAE (Semantic-Temporal Aware Eviction): centroid-temporal hybrid scoring for dialogue compression
  • SemToken: pre-processing that identifies and removes redundant spans before chunking
  • COMI: coarse-to-fine query-guided compression that focuses on query-relevant content
  • Together, these achieve 85%+ compression on typical documents while maintaining 90%+ semantic fidelity.

    Try It Yourself

    Paste any text into our playground and see the compression in action. No signup required.

    Start compressing →

    Cite this

    Researchers, analysts, or journalists referencing this post can use either format below — both are copyable.

    BibTeXbibtex
    @misc{context-window-optimization-2026,
      title  = {Context Window Optimization: Beyond Naive Truncation},
      author = {James Hollingsworth},
      year   = {2026},
      month  = {April},
      url    = {https://www.gotcontext.ai/blog/context-window-optimization},
      note   = {gotcontext.ai engineering blog.},
    }
    APAtext
    James Hollingsworth. (2026, April 10). Context Window Optimization: Beyond Naive Truncation. gotcontext.ai. Retrieved from https://www.gotcontext.ai/blog/context-window-optimization.

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