chore(vendor): import pi 1.3.0

Imported as a linear vendor commit so forge rebases do not replay the upstream root tree.

git-subtree-dir: third_party/pi

git-subtree-split: 71023aec1546d6d677a65669c5665c0927ce0dd0

third_party/pi/packages/coding-agent/test/compaction.test.ts

@@ -373,6 +373,42 @@ describe("findCutPoint", () => {
 		expect(customFitsBudget.isSplitTurn).toBe(false);
 		expect(customFitsBudget.turnStartIndex).toBe(-1);
 	});
+
+	// Regression test for #9740.
+	it("should fall back to the latest valid cut point before oversized trailing tool results", () => {
+		const oldUser = createMessageEntry(createUserMessage("old history"));
+		const oldAssistant = createMessageEntry(createAssistantMessage("old answer"));
+		const currentUser = createMessageEntry(createUserMessage("read the large file"));
+		const toolCall = createMessageEntry({
+			...createAssistantMessage(""),
+			content: [{ type: "toolCall", id: "call-1", name: "read", arguments: { path: "big.txt" } }],
+			stopReason: "toolUse",
+		});
+		const toolResult = createMessageEntry({
+			role: "toolResult",
+			toolCallId: "call-1",
+			toolName: "read",
+			content: [{ type: "text", text: "x".repeat(8000) }],
+			isError: false,
+			timestamp: Date.now(),
+		});
+		const entries = [oldUser, oldAssistant, currentUser, toolCall, toolResult];
+
+		const result = findCutPoint(entries, 0, entries.length, 1000);
+		expect(result).toEqual({
+			firstKeptEntryIndex: 3,
+			turnStartIndex: 2,
+			isSplitTurn: true,
+		});
+
+		const preparation = prepareCompaction(entries, {
+			...DEFAULT_COMPACTION_SETTINGS,
+			keepRecentTokens: 1000,
+		});
+		expect(preparation?.firstKeptEntryId).toBe(toolCall.id);
+		expect(preparation?.messagesToSummarize).toEqual([oldUser.message, oldAssistant.message]);
+		expect(preparation?.turnPrefixMessages).toEqual([currentUser.message]);
+	});
 });
 
 describe("buildSessionContext", () => {
@@ -461,6 +497,29 @@ describe("buildSessionContext", () => {
 	});
 });
 
+describe("prepareCompaction", () => {
+	it("does not treat system messages as conversation history", () => {
+		const system = createMessageEntry({
+			role: "system",
+			content: "",
+			sections: { preamble: "current prompt" },
+			timestamp: Date.now(),
+		});
+		const user = createMessageEntry(createUserMessage("one long turn"));
+		const assistant = createMessageEntry(createAssistantMessage("assistant suffix"));
+		const preparation = prepareCompaction([system, user, assistant], {
+			...DEFAULT_COMPACTION_SETTINGS,
+			keepRecentTokens: 1,
+		});
+
+		expect(preparation).toBeDefined();
+		expect(preparation?.firstKeptEntryId).toBe(assistant.id);
+		expect(preparation?.isSplitTurn).toBe(true);
+		expect(preparation?.messagesToSummarize).toEqual([]);
+		expect(preparation?.turnPrefixMessages).toEqual([user.message]);
+	});
+});
+
 describe("prepareCompaction with previous compaction", () => {
 	it("should skip repeated compactions when kept messages still fit", () => {
 		const u1 = createMessageEntry(createUserMessage("user msg 1 (summarized by compaction1)"));