EvanFlow: Compact

Why this exists: Context drift kills agents before context limits do. Industry research found ~65% of enterprise AI failures in 2025 traced to context drift or memory loss in multi-step reasoning, NOT raw token exhaustion. The agent's ability to reason degrades as context fills with stale, redundant, or contradictory information — long before the hard token limit.

Vocabulary

See evanflow meta-skill. Specific to this skill:

• Drift — agent reasoning degrades as context fills with stale/contradictory/low-signal content. Manifests as: slower responses, more clarifying questions about already-established facts, forgetting recent decisions, inconsistent application of rules.
• Anchor — a high-signal artifact (CONTEXT.md, ADR, current plan, current diff) that survives compaction.
• Compaction — replacing a long stretch of conversation with a shorter summary that preserves the anchors plus key decisions.
• Branch isolation — moving a side-quest into a separate session so the main session stays focused.

When to Use

Trigger this skill when ANY of these are true:

• A major phase boundary just completed (e.g., Phase A done, about to start Phase B). Proactive compaction at clean boundaries is much higher quality than reactive compaction mid-flow.