Module compression 

Experience compression spectrum (#3305).

This module implements a three-tier memory retrieval policy and a background promotion engine that converts recurring episodic patterns into generated SKILL.md files.

Tiers

Tier	Description
Episodic	Raw conversation snippets, lowest abstraction, highest token cost.
Procedural	Tool-use patterns and how-to knowledge.
Declarative	Stable facts and reference knowledge.

Retrieval policy

RetrievalPolicy maps the current remaining token-budget ratio to a subset of tiers. When the budget is ample (> mid_budget_ratio) all three tiers are queried; as the budget narrows, cheaper tiers are preferred.

Promotion engine

promotion::PromotionEngine scans a window of recent episodic messages for clustering patterns and promotes qualifying clusters to SKILL.md files.

Re-exports

pub use promotion::PromotionCandidate;

pub use promotion::PromotionConfig;

pub use promotion::PromotionEngine;

pub use promotion::PromotionInput;

Modules

promotion

Background skill-promotion engine (#3305).

Structs

RetrievalPolicy

Token-budget-aware tier selector for context assembly.

Enums

CompressionLevel

The three abstraction levels in the compression spectrum.