Phase 6: add compaction coexistence hint — one-time notify when both compactors run.

Shows ui.notify once when pi-auto-compact is detected while Pi compaction.enabled stays true.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/auto-compact.ts

@@ -1,4 +1,5 @@
-import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
+import type { ExtensionAPI, ExtensionContext } from "@earendil-works/pi-coding-agent";
+import { SettingsManager, getAgentDir } from "@earendil-works/pi-coding-agent";
 import {
 	effectiveIntegration,
 	type ReinjectDeliveryMode,
@@ -33,3 +34,57 @@ export const PI_AUTO_COMPACT_FOLLOW_UP_PREFIXES = [
 	"Emergency auto-compact ran.",
 	"Auto-compact ran on session resume.",
 ] as const;
+
+const PI_DEFAULT_COMPACTION_ENABLED = true;
+
+function readCompactionEnabled(settings: object): boolean | undefined {
+	const compaction = (settings as Record<string, unknown>).compaction;
+	if (!compaction || typeof compaction !== "object" || Array.isArray(compaction)) {
+		return undefined;
+	}
+	const enabled = (compaction as Record<string, unknown>).enabled;
+	return typeof enabled === "boolean" ? enabled : undefined;
+}
+
+/** Merged Pi compaction.enabled with project-over-global semantics (SPEC §16.7). */
+export function resolvePiDefaultCompactionEnabled(
+	globalSettings: object,
+	projectSettings: object,
+): boolean {
+	return (
+		readCompactionEnabled(projectSettings) ??
+		readCompactionEnabled(globalSettings) ??
+		PI_DEFAULT_COMPACTION_ENABLED
+	);
+}
+
+export function isPiDefaultCompactionEnabled(ctx: ExtensionContext): boolean {
+	const manager = SettingsManager.create(ctx.cwd, getAgentDir(), {
+		projectTrusted: ctx.isProjectTrusted(),
+	});
+	return resolvePiDefaultCompactionEnabled(
+		manager.getGlobalSettings(),
+		manager.getProjectSettings(),
+	);
+}
+
+/** One-time ui.notify when Pi default compaction and pi-auto-compact are both active (SPEC §16.7). */
+export function maybeNotifyCompactionCoexistenceHint(
+	ctx: ExtensionContext,
+	runtime: RuntimeFlags,
+	piDefaultCompactionEnabled = isPiDefaultCompactionEnabled(ctx),
+): void {
+	if (runtime.compactionCoexistenceHintShown || !runtime.autoCompactDetected) {
+		return;
+	}
+	if (!piDefaultCompactionEnabled) {
+		return;
+	}
+	if (ctx.hasUI) {
+		ctx.ui.notify(
+			"Pi built-in auto-compaction and pi-auto-compact are both enabled. Consider setting compaction.enabled to false in settings.json.",
+			"info",
+		);
+	}
+	runtime.compactionCoexistenceHintShown = true;
+}

src/state.ts

@@ -31,6 +31,8 @@ export interface ExtensionState {
 export interface RuntimeFlags {
 	autoCompactDetected: boolean;
 	autoCompactIntegration: AutoCompactIntegration;
+	/** One-time hint when Pi default compaction coexists with pi-auto-compact (SPEC §16.7). */
+	compactionCoexistenceHintShown: boolean;
 }
 
 export const STATE_ENTRY_TYPE = "skill-reinject:state";
@@ -84,6 +86,7 @@ export function createRuntimeFlags(): RuntimeFlags {
 	return {
 		autoCompactDetected: false,
 		autoCompactIntegration: "auto",
+		compactionCoexistenceHintShown: false,
 	};
 }