fix(compaction): manual /shake keeps a recent tail of tool results

Manual /shake used protectTokens: 0, stripping every eligible tool result
including the ones the agent is still working from. Keep a small 4k-token
recent window (matching the automatic shake mechanism, at a quarter of its
16k budget) so the full escape hatch stays aggressive without destroying
the live tail. Two matcher-focused tests that implicitly relied on the
zero window now pin protectTokens: 0 explicitly.

Fixes #7776

packages/agent/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- Manual `/shake` now keeps a small recent tail of tool results instead of stripping every eligible result, so the agent does not lose the context it is currently working from ([#7776](https://github.com/can1357/oh-my-pi/issues/7776)).
+
 ## [17.2.10] - 2026-08-06
 
 ### Fixed

packages/agent/src/compaction/shake.ts

@@ -52,11 +52,13 @@ export const DEFAULT_SHAKE_CONFIG: ShakeConfig = {
 };
 
 /**
- * Manual `/shake`: aggressive — drops every eligible region across history,
- * artifact recovery reads included (the user's full escape hatch).
+ * Manual `/shake`: aggressive — no savings threshold and drops eligible
+ * regions across history, artifact recovery reads included (the user's full
+ * escape hatch). Still keeps a small recent tail so it cannot strip the tool
+ * results the agent is currently working from (#7776).
  */
 export const AGGRESSIVE_SHAKE_CONFIG: ShakeConfig = {
-	protectTokens: 0,
+	protectTokens: 4_000,
 	minSavings: 0,
 	protectedTools: ["skill", isSkillReadToolResult],
 	fenceMinTokens: 400,

packages/agent/test/shake.test.ts

@@ -204,12 +204,23 @@ describe("applyShakeRegions — multi-region ordering", () => {
 });
 
 describe("shake config presets", () => {
-	test("aggressive preset protects skill and drops everything else", () => {
-		expect(AGGRESSIVE_SHAKE_CONFIG.protectTokens).toBe(0);
+	test("aggressive preset protects skill and keeps a small recent tail", () => {
+		expect(AGGRESSIVE_SHAKE_CONFIG.protectTokens).toBeGreaterThan(0);
 		expect(AGGRESSIVE_SHAKE_CONFIG.minSavings).toBe(0);
 		expect(AGGRESSIVE_SHAKE_CONFIG.protectedTools).toContain("skill");
 	});
 
+	test("manual shake preserves the recent tool-result tail instead of stripping everything", () => {
+		const older = messageEntry(toolResultMessage("bash", "old-result ".repeat(300)));
+		const recent = messageEntry(toolResultMessage("bash", "recent-result ".repeat(3000)));
+		const regions = collectShakeRegions([older, recent], AGGRESSIVE_SHAKE_CONFIG);
+
+		// The recent result sits inside the preserved tail; the older one is
+		// still shaken aggressively.
+		expect(regions).toHaveLength(1);
+		expect(regions[0].entry).toBe(older);
+	});
+
 	test("default preset keeps a protect window", () => {
 		expect(DEFAULT_SHAKE_CONFIG.protectTokens).toBeGreaterThan(0);
 		expect(DEFAULT_SHAKE_CONFIG.protectedTools).toContain("skill");

packages/agent/test/tool-protection.test.ts

@@ -84,7 +84,9 @@ describe("conditional tool-result protection", () => {
 			fileResult,
 		];
 
-		const regions = collectShakeRegions(entries, AGGRESSIVE_SHAKE_CONFIG);
+		// protectTokens: 0 isolates the matcher behavior from the aggressive
+		// preset's recent-tail window (covered by shake.test.ts).
+		const regions = collectShakeRegions(entries, { ...AGGRESSIVE_SHAKE_CONFIG, protectTokens: 0 });
 
 		expect(regions).toHaveLength(1);
 		expect(regions[0]?.kind).toBe("toolResult");

packages/coding-agent/test/plan-mode/plan-protection.test.ts

@@ -155,6 +155,7 @@ describe("plan-read protection in compaction", () => {
 
 		const regions = collectShakeRegions(entries, {
 			...AGGRESSIVE_SHAKE_CONFIG,
+			protectTokens: 0,
 			protectedTools: [...AGGRESSIVE_SHAKE_CONFIG.protectedTools, matcher],
 		});