Synthesis Checkpoint — Mid-Session Refresh & Drift Recovery

The Problem

LLMs are stateless at the model level. Across a long conversation, an LLM's sense of "what's true now" can drift from what's actually on disk and in git. Drift sources:

• Time drift. The model has no clock. If the conversation started Tuesday and continues Wednesday, the model often still thinks it's Tuesday.
• State drift. Project CONTEXT.md may have been edited (by user, by sub-agent, by another session) since the model last read it.
• Compaction drift. When the context window approaches its limit, the harness may summarize older turns. Details disappear. The model often cannot detect that this happened.
• Cached-fact drift. Facts the model read earlier in the conversation (last commit, last session date, last decision) may no longer be true.
• Coordination drift. Another live root session may have claimed or changed the same source area since the last tool call.

Self-discipline degrades with conversation length. Rules read at session start lose salience as turns accumulate. Even a model that "knows" to verify often skips verification under the weight of accumulated context.

This skill is the recovery primitive. It is a tight, low-friction protocol the agent runs on demand or on a detected drift signal — and the act of running it restores ground truth.

When To Invoke