feat: implemented token tracking and metadata options for compaction summaries

- Added `CompactionSummaryMessageOptions` interface to support optional fields and metadata in compaction summary messages.
- Included compaction method labels and before-after amount badge rendering in compaction views.
- Updated session maintenance and compaction methods to track and compute post-compaction token counts.
- Updated calls across agent and coding-agent packages to use the new compaction options object.

packages/coding-agent/test/agent-session-snapcompact-frame-dead-end.test.ts

@@ -160,9 +160,10 @@ describe("AgentSession snapcompact frame dead-end rescue", () => {
 				"stale snapcompact archive",
 				userEntryId,
 				150_000,
-				{ readFiles: ["src/a.ts"], modifiedFiles: ["src/b.ts"] },
-				false,
-				makeArchivePreserveData(options.frameCount),
+				{
+					details: { readFiles: ["src/a.ts"], modifiedFiles: ["src/b.ts"] },
+					preserveData: makeArchivePreserveData(options.frameCount),
+				},
 			);
 		}
 

packages/coding-agent/test/modes/components/compaction-divider.test.ts

@@ -20,7 +20,7 @@ const SUMMARY = "Earlier the user fixed the login TTL bug.";
 
 function makeComponent(images?: ImageContent[]): CompactionSummaryMessageComponent {
 	return new CompactionSummaryMessageComponent(
-		createCompactionSummaryMessage(SUMMARY, 84000, new Date().toISOString(), undefined, undefined, images),
+		createCompactionSummaryMessage(SUMMARY, 84000, new Date().toISOString(), { images }),
 	);
 }
 
@@ -36,6 +36,29 @@ describe("CompactionSummaryMessageComponent", () => {
 		expect(rule).not.toContain(SUMMARY);
 	});
 
+	it("names the compaction method and the before → after amounts on the divider", () => {
+		const component = new CompactionSummaryMessageComponent(
+			createCompactionSummaryMessage(SUMMARY, 256_000, new Date().toISOString(), {
+				method: "remote",
+				tokensAfter: 20_000,
+			}),
+		);
+		const rule = Bun.stripANSI(component.render(80)[1]);
+		expect(rule).toContain("remote-compacted");
+		expect(rule).toContain("256K→20K");
+		expect(rule).toContain("ctrl+o");
+	});
+
+	it("labels a handoff-method compaction as handed-off", () => {
+		const component = new CompactionSummaryMessageComponent(
+			createCompactionSummaryMessage(SUMMARY, 84_000, new Date().toISOString(), { method: "handoff" }),
+		);
+		const rule = Bun.stripANSI(component.render(80)[1]);
+		expect(rule).toContain("handed-off");
+		// No tokensAfter recorded → no amount badge.
+		expect(rule).not.toContain("→");
+	});
+
 	it("expanded: reveals the summary (and snapcompact frame count) below the divider", () => {
 		const component = makeComponent([{ type: "image", data: "ZmFrZQ==", mimeType: "image/png" }]);
 		component.setExpanded(true);

packages/coding-agent/test/modes/components/compaction-summary-message.test.ts

@@ -39,7 +39,7 @@ describe("handoff summary divider", () => {
 
 		expect(component).toBeInstanceOf(HandoffSummaryMessageComponent);
 		const collapsed = Bun.stripANSI(component!.render(80).join("\n"));
-		expect(collapsed).toContain("handoff");
+		expect(collapsed).toContain("handed-off");
 		expect(collapsed).toContain("ctrl+o");
 		expect(collapsed).not.toContain("[handoff]");
 		expect(collapsed).not.toContain("Continue the resize fix");

packages/coding-agent/test/session-manager/large-session-memory.test.ts

@@ -82,15 +82,9 @@ describe("large session memory guards", () => {
 				textTail: "frame",
 			},
 		};
-		const firstCompactionId = session.appendCompaction(
-			firstSummary,
-			undefined,
-			firstKeptEntryId,
-			1000,
-			undefined,
-			undefined,
-			firstPreserve,
-		);
+		const firstCompactionId = session.appendCompaction(firstSummary, undefined, firstKeptEntryId, 1000, {
+			preserveData: firstPreserve,
+		});
 		const rewindId = session.appendMessage({ role: "user", content: "between compactions", timestamp: 3 });
 		session.appendCompaction(secondSummary, undefined, rewindId, 2000);
 		await session.flush();
@@ -188,15 +182,9 @@ describe("large session memory guards", () => {
 
 		const branchACompactionSummary = `branch-a-${"x".repeat(1024)}`;
 		const branchAPreserve = { openaiRemoteCompaction: { provider: "anthropic", replacementHistory: [] } };
-		session.appendCompaction(
-			branchACompactionSummary,
-			undefined,
-			rootId,
-			1000,
-			undefined,
-			undefined,
-			branchAPreserve,
-		);
+		session.appendCompaction(branchACompactionSummary, undefined, rootId, 1000, {
+			preserveData: branchAPreserve,
+		});
 		const branchACompactionId = session.getLeafId();
 		if (!branchACompactionId) throw new Error("Expected branch A compaction id");
 

packages/coding-agent/test/shake.test.ts

@@ -219,10 +219,13 @@ describe("AgentSession shake", () => {
 			seedHeavyToolResult("X".repeat(20_000));
 			const firstKeptEntryId = sessionManager.getBranch()[0]?.id;
 			if (!firstKeptEntryId) throw new Error("Expected seeded branch");
-			sessionManager.appendCompaction("remote summary", undefined, firstKeptEntryId, 10_000, {}, false, {
-				openaiRemoteCompaction: {
-					provider: "openai",
-					replacementHistory: [],
+			sessionManager.appendCompaction("remote summary", undefined, firstKeptEntryId, 10_000, {
+				details: {},
+				preserveData: {
+					openaiRemoteCompaction: {
+						provider: "openai",
+						replacementHistory: [],
+					},
 				},
 			});
 			sessionManager.appendMessage({