# Common Context Optimization

> Techniques to maximize context window efficiency, reduce latency, and prevent 'lost in middle' issues through strategic masking and compaction. (triggers: *.log, chat-history.json, reduce tokens, optimize context, summarize history, clear output)

- Skill: `comeonoliver/common-context-optimization` (Agent Skill)
- Install (CLI): `npx skillmds@latest add comeonoliver/common-context-optimization`
- Raw SKILL.md: https://api.skillmd.com/api/skills/comeonoliver/common-context-optimization/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: ComeOnOliver (https://skillmd.com/u/comeonoliver)
- Updated: 2026-09-08
- Page: https://skillmd.com/skills/comeonoliver/common-context-optimization

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## **Priority: P1 (OPTIMIZATION)**

Manage the Attention Budget. Treat context as a scarce resource.

## 1. Observation Masking (Noise Reduction)

**Problem**: Large tool outputs (logs, JSON lists) flood context and degrade reasoning.
**Solution**: Replace raw output with semantic summaries _after_ consumption.

1.  **Identify**: outputs > 50 lines or > 1kb.
2.  **Extract**: Read critical data points immediately.
3.  **Mask**: Rewrite history to replace raw data with `[Reference: <summary_of_findings>]`.
4.  **See**: `references/masking.md` for patterns.

## 2. Context Compaction (State Preservation)

**Problem**: Long conversations drift from original intent.
**Solution**: Recursive summarization that preserves _State_ over _Dialogue_.

1.  **Trigger**: Every 10 turns or 8k tokens.
2.  **Compact**:
    - **Keep**: User Goal, Active Task, Current Errors, Key Decisions.
    - **Drop**: Chat chit-chat, intermediate tool calls, corrected assumptions.
3.  **Format**: Update `System Prompt` or `Memory File` with compacted state.
4.  **See**: `references/compaction.md` for algorithms.

## 3. KV-Cache Awareness (Latency)

**Goal**: Maximize pre-fill cache hits.

- **Static Prefix**: strict ordering: System -> Tools -> RAG -> User.
- **Append-Only**: Avoid inserting into the middle of history if possible.

## References

- [Observation Masking Patterns](references/masking.md)
- [Compaction Algorithms](references/compaction.md)


## Anti-Patterns

- **No raw tool dumps**: Mask large outputs immediately after extracting data.
- **No append-only growth**: Compact every 10 turns to preserve intent over dialogue.
- **No middle insertions**: Append-only history maximizes KV cache hits.