# Session & Context Management

## Why This Matters

Context is the most precious resource in a Claude Code session. The 200k token window seems large but fills fast — especially with MCP tools, long files, and multi-step tasks. Community consensus: managing context deliberately is a 2-3x productivity multiplier.

## Current State

- No explicit context management practices documented
- Auto-memory system is configured (built-in)
- No compaction hooks

## Key Practices

### Session Hygiene
- **Use `/clear` between unrelated tasks.** A fresh session costs ~20k tokens (10% of budget), leaving ~180k for work. Polluted context from failed approaches actively degrades output quality.
- **After two failed corrections, `/clear` and start fresh.** Context is now polluted with failed approaches. Write a better initial prompt instead.
- **One task per session.** The "kitchen sink session" (start task A, ask about B, return to A) is a documented anti-pattern.

### Context Budgeting
- **Use `/context` to audit token usage.** MCP tools consume context even when unused. Browser automation tools alone can eat 8-30% of available context.
- **Remove unused MCP servers** from settings when not actively needed.
- **Compact proactively at 60-70% usage** — don't wait for auto-compact.

### Extended Thinking
- **Only `ultrathink` activates extended thinking** as of Claude Code v2.0.0. Previous keywords like "think" or "think hard" no longer work.
- Use `ultrathink` for complex reasoning tasks, architectural decisions, and debugging subtle issues.

### Compaction Strategy
- Default reserves 32k tokens (22.5% of 200k) for auto-compact buffer.
- Setting `CLAUDE_CODE_MAX_OUTPUT_TOKENS` to 64k increases the buffer to ~40%.
- **PreCompact hook** (see hooks-and-automation.md) saves transcript before compaction.
- Pair with auto-memory: gradual learning via memory, emergency snapshots via PreCompact hooks.

### Handoff Between Sessions
- Before ending a long session, create a handoff document: goals, progress, blockers, next steps.
- A `/handoff` or `/catchup` skill (see skills-and-progressive-disclosure.md) automates this.
- "Context is like milk — keep it fresh and condensed."