fix(agents): harden compaction and reset safety

Co-authored-by: jaden-clovervnd <91520439+jaden-clovervnd@users.noreply.github.com>
Co-authored-by: Sid <201593046+Sid-Qin@users.noreply.github.com>
Co-authored-by: Marcus Widing <245375637+widingmarcus-cyber@users.noreply.github.com>

src/agents/pi-extensions/compaction-safeguard.test.ts

@@ -428,3 +428,59 @@ describe("compaction-safeguard extension model fallback", () => {
     expect(getApiKeyMock).not.toHaveBeenCalled();
   });
 });
+
+describe("compaction-safeguard double-compaction guard", () => {
+  it("cancels compaction when there are no real messages to summarize", async () => {
+    const sessionManager = stubSessionManager();
+    const model = createAnthropicModelFixture();
+    setCompactionSafeguardRuntime(sessionManager, { model });
+
+    const compactionHandler = createCompactionHandler();
+    const mockEvent = {
+      preparation: {
+        messagesToSummarize: [] as AgentMessage[],
+        turnPrefixMessages: [] as AgentMessage[],
+        firstKeptEntryId: "entry-1",
+        tokensBefore: 1500,
+        fileOps: { read: [], edited: [], written: [] },
+      },
+      customInstructions: "",
+      signal: new AbortController().signal,
+    };
+
+    const getApiKeyMock = vi.fn().mockResolvedValue("sk-test");
+    const mockContext = createCompactionContext({
+      sessionManager,
+      getApiKeyMock,
+    });
+
+    const result = (await compactionHandler(mockEvent, mockContext)) as {
+      cancel?: boolean;
+    };
+    expect(result).toEqual({ cancel: true });
+    expect(getApiKeyMock).not.toHaveBeenCalled();
+  });
+
+  it("continues when messages include real conversation content", async () => {
+    const sessionManager = stubSessionManager();
+    const model = createAnthropicModelFixture();
+    setCompactionSafeguardRuntime(sessionManager, { model });
+
+    const compactionHandler = createCompactionHandler();
+    const mockEvent = createCompactionEvent({
+      messageText: "real message",
+      tokensBefore: 1500,
+    });
+    const getApiKeyMock = vi.fn().mockResolvedValue(null);
+    const mockContext = createCompactionContext({
+      sessionManager,
+      getApiKeyMock,
+    });
+
+    const result = (await compactionHandler(mockEvent, mockContext)) as {
+      cancel?: boolean;
+    };
+    expect(result).toEqual({ cancel: true });
+    expect(getApiKeyMock).toHaveBeenCalled();
+  });
+});

src/agents/pi-extensions/compaction-safeguard.ts

@@ -130,6 +130,10 @@ function formatToolFailuresSection(failures: ToolFailure[]): string {
   return `\n\n## Tool Failures\n${lines.join("\n")}`;
 }
 
+function isRealConversationMessage(message: AgentMessage): boolean {
+  return message.role === "user" || message.role === "assistant" || message.role === "toolResult";
+}
+
 function computeFileLists(fileOps: FileOperations): {
   readFiles: string[];
   modifiedFiles: string[];
@@ -191,6 +195,12 @@ async function readWorkspaceContextForSummary(): Promise<string> {
 export default function compactionSafeguardExtension(api: ExtensionAPI): void {
   api.on("session_before_compact", async (event, ctx) => {
     const { preparation, customInstructions, signal } = event;
+    if (!preparation.messagesToSummarize.some(isRealConversationMessage)) {
+      log.warn(
+        "Compaction safeguard: cancelling compaction with no real conversation messages to summarize.",
+      );
+      return { cancel: true };
+    }
     const { readFiles, modifiedFiles } = computeFileLists(preparation.fileOps);
     const fileOpsSummary = formatFileOperations(readFiles, modifiedFiles);
     const toolFailures = collectToolFailures([