fix: add compaction headroom for memory writes

src/agents/pi-embedded-runner.ts

@@ -69,6 +69,7 @@ import {
 import { normalizeModelCompat } from "./model-compat.js";
 import { ensureClawdbotModelsJson } from "./models-config.js";
 import type { MessagingToolSend } from "./pi-embedded-messaging.js";
+import { ensurePiCompactionReserveTokens } from "./pi-settings.js";
 import { acquireSessionWriteLock } from "./session-write-lock.js";
 
 export type { MessagingToolSend } from "./pi-embedded-messaging.js";
@@ -981,6 +982,7 @@ export async function compactEmbeddedPiSession(params: {
             effectiveWorkspace,
             agentDir,
           );
+          ensurePiCompactionReserveTokens({ settingsManager });
           const additionalExtensionPaths = buildEmbeddedExtensionPaths({
             cfg: params.config,
             sessionManager,
@@ -1369,6 +1371,7 @@ export async function runEmbeddedPiAgent(params: {
             effectiveWorkspace,
             agentDir,
           );
+          ensurePiCompactionReserveTokens({ settingsManager });
           const additionalExtensionPaths = buildEmbeddedExtensionPaths({
             cfg: params.config,
             sessionManager,

src/agents/pi-settings.test.ts

@@ -0,0 +1,37 @@
+import { describe, expect, it, vi } from "vitest";
+
+import {
+  DEFAULT_PI_COMPACTION_RESERVE_TOKENS_FLOOR,
+  ensurePiCompactionReserveTokens,
+} from "./pi-settings.js";
+
+describe("ensurePiCompactionReserveTokens", () => {
+  it("bumps reserveTokens when below floor", () => {
+    const settingsManager = {
+      getCompactionReserveTokens: () => 16_384,
+      applyOverrides: vi.fn(),
+    };
+
+    const result = ensurePiCompactionReserveTokens({ settingsManager });
+
+    expect(result).toEqual({
+      didOverride: true,
+      reserveTokens: DEFAULT_PI_COMPACTION_RESERVE_TOKENS_FLOOR,
+    });
+    expect(settingsManager.applyOverrides).toHaveBeenCalledWith({
+      compaction: { reserveTokens: DEFAULT_PI_COMPACTION_RESERVE_TOKENS_FLOOR },
+    });
+  });
+
+  it("does not override when already above floor", () => {
+    const settingsManager = {
+      getCompactionReserveTokens: () => 32_000,
+      applyOverrides: vi.fn(),
+    };
+
+    const result = ensurePiCompactionReserveTokens({ settingsManager });
+
+    expect(result).toEqual({ didOverride: false, reserveTokens: 32_000 });
+    expect(settingsManager.applyOverrides).not.toHaveBeenCalled();
+  });
+});

src/agents/pi-settings.ts

@@ -0,0 +1,27 @@
+export const DEFAULT_PI_COMPACTION_RESERVE_TOKENS_FLOOR = 20_000;
+
+type PiSettingsManagerLike = {
+  getCompactionReserveTokens: () => number;
+  applyOverrides: (overrides: {
+    compaction: { reserveTokens: number };
+  }) => void;
+};
+
+export function ensurePiCompactionReserveTokens(params: {
+  settingsManager: PiSettingsManagerLike;
+  minReserveTokens?: number;
+}): { didOverride: boolean; reserveTokens: number } {
+  const minReserveTokens =
+    params.minReserveTokens ?? DEFAULT_PI_COMPACTION_RESERVE_TOKENS_FLOOR;
+  const current = params.settingsManager.getCompactionReserveTokens();
+
+  if (current >= minReserveTokens) {
+    return { didOverride: false, reserveTokens: current };
+  }
+
+  params.settingsManager.applyOverrides({
+    compaction: { reserveTokens: minReserveTokens },
+  });
+
+  return { didOverride: true, reserveTokens: minReserveTokens };
+}