/**
 * L2 — context-economy primitives, the MECHANICAL half.
 *
 * The kernel's compaction policy is identity preservation, not summary
 * (mauri ADR-0007): keep the message SHELL (id, role, position), replace
 * the content with a marker, zero LLM calls. A summary is a NEW message; it
 * never rewrites an old one. Messages are immutable (ADR-0002) — "clearing"
 * is append, not mutation.
 *
 * ADR-0044 merged the classic auto-compaction (`config.compaction` +
 * `compacted` events) INTO the microcompact boundary: the loop no longer
 * produces `compacted` events (the boundary's projection derives the same
 * cleared view deterministically), and this module now holds only what the
 * live path shares. Old sessions' `compacted` events still replay verbatim
 * — see kernel/project.ts.
 *
 * The model-generated half of context economy (the /compact summary layer)
 * lives in kernel/summarize.ts.
 */
import type { Message } from "../protocol/messages.js";
/**
 * Rough token estimate (chars/4 + structural overhead). Calibration-free on
 * purpose: context economy only needs a stable MONOTONE proxy, not an exact
 * count — the threshold absorbs the error (mauri ADR-0007). The proxy's
 * three-word contract, and the pins that hold it, are
 * packages/core/tests/sc1b-estimator.test.ts.
 */
export declare function estimateTokens(messages: readonly Message[]): number;