/context-window-management

name: context-window-management
description: "Manage LLM context budgets—prioritization, summarization, compaction, and what to load vs reference. Use for long sessions, large repos, or multi-doc tasks."
allowed-tools: Read, Glob, Grep

Context window management

Lifecycle

| Phase | Action | |-------|--------| | Bootstrap | Load spec, constraints, key paths only—not whole repo | | During task | Append deltas; replace full file reads with summaries after use | | Before compaction | Write `Session state` block (objective, done, open, paths) | | Session end | Drop tool noise; keep decisions and verification evidence |

Strategy order

1. **Do not load** — use search/read targeted files only. 2. **Reference** — pointers (paths, line ranges) instead of full paste. 3. **Summarize** — compress completed work; keep decisions and open items. 4. **Drop** — remove obsolete tool output and duplicated content.

What to keep in active context

• Current objective and acceptance criteria
• Constraints (env, versions, "do not touch")
• Recent errors and fixes
• Open questions

What to offload

• Full file contents already summarized
• Long command outputs (keep exit code + last N lines)
• Exploratory branches that did not ship

Compaction pattern

## Session state (compacted)
Objective: ...
Done: ...
Open: ...
Key paths: ...
Do not repeat: [list already-established facts]

Multi-file work

• Load one module at a time when possible.
• Prefer ripgrep/semantic search over dumping trees.
• For RAG: retrieve only top-k relevant chunks.

Anti-patterns

• Pasting entire repos or logs into chat.
• Re-explaining architecture every turn without delta.
• Keeping failed attempts at full length after resolution.

Session setup (context engineering)

Before long tasks, establish a minimal working set:

1. **Objective block** — one paragraph: goal, non-goals, done-when 2. **Constraint block** — versions, env, files off-limits 3. **Reference map** — paths to spec, ADR, or ticket; load on demand 4. **Tool policy** — which tools/skills apply; avoid loading unused skill bodies

Refresh the objective block after major pivots; do not re-paste full history.

Pairing

Use with `rag-systems` for external knowledge; `clarify-underspecified` when scope grows mid-session; `interview-me` before loading large specs.