context-budget

# Context budget The context window is RAM, not a hard drive. Full ≠ free: a window stuffed to 95% does not just cost more money, it *reasons worse*. Model performance degrades as input tokens grow — even well inside the stated limit, every token added depletes a finite attention budget (Chroma "Context Rot" research, accessed 2026-06-02). Your job on a long task is to keep the *live* window lean and externalise everything else, so the work can run for hours across many fresh windows without losing the thread. > **The one rule:** if you can reconstruct a thing from a file or from git, it does not belong resident in the window. Keep load-bearing-right-now; evict the rest. The cost of forgetting is one re-read; the cost of hoarding is silent quality rot on every turn that follows. Neighbours, so you don't do their job here: pricing tokens, spend ledgers and hard `$` caps are `../cost-tracking/SKILL.md` — same words ("token budget"), different unit, dollars vs. attention. Finding the *right* context via embeddings/chunking is `../rag/SKILL.md`; RAG is *how you find* context, this is *how much* you let live and *when to evict*. Prompt text, few-shot and output format are `../prompt-engineering/SKILL.md`; the agent loop, tool schemas and provider adapters are `../building-agents/SKILL.md`; partition-then-gather fan-out of independent work is `../parallel/SKILL.md` (this skill *uses* subagents as a context-isolation tactic but does not own that discipline); the 01-TOOLS / 02-DOC...