feat: add cache-ttl pruning mode

src/agents/pi-embedded-runner/cache-ttl.ts

@@ -0,0 +1,52 @@
+type CustomEntryLike = { type?: unknown; customType?: unknown; data?: unknown };
+
+export const CACHE_TTL_CUSTOM_TYPE = "clawdbot.cache-ttl";
+
+export type CacheTtlEntryData = {
+  timestamp: number;
+  provider?: string;
+  modelId?: string;
+};
+
+export function isCacheTtlEligibleProvider(provider: string, modelId: string): boolean {
+  const normalizedProvider = provider.toLowerCase();
+  const normalizedModelId = modelId.toLowerCase();
+  if (normalizedProvider === "anthropic") return true;
+  if (normalizedProvider === "openrouter" && normalizedModelId.startsWith("anthropic/"))
+    return true;
+  return false;
+}
+
+export function readLastCacheTtlTimestamp(sessionManager: unknown): number | null {
+  const sm = sessionManager as { getEntries?: () => CustomEntryLike[] };
+  if (!sm?.getEntries) return null;
+  try {
+    const entries = sm.getEntries();
+    let last: number | null = null;
+    for (let i = entries.length - 1; i >= 0; i--) {
+      const entry = entries[i];
+      if (entry?.type !== "custom" || entry?.customType !== CACHE_TTL_CUSTOM_TYPE) continue;
+      const data = entry?.data as Partial<CacheTtlEntryData> | undefined;
+      const ts = typeof data?.timestamp === "number" ? data.timestamp : null;
+      if (ts && Number.isFinite(ts)) {
+        last = ts;
+        break;
+      }
+    }
+    return last;
+  } catch {
+    return null;
+  }
+}
+
+export function appendCacheTtlTimestamp(sessionManager: unknown, data: CacheTtlEntryData): void {
+  const sm = sessionManager as {
+    appendCustomEntry?: (customType: string, data: unknown) => void;
+  };
+  if (!sm?.appendCustomEntry) return;
+  try {
+    sm.appendCustomEntry(CACHE_TTL_CUSTOM_TYPE, data);
+  } catch {
+    // ignore persistence failures
+  }
+}

src/agents/pi-embedded-runner/extensions.ts

@@ -11,6 +11,7 @@ import { setContextPruningRuntime } from "../pi-extensions/context-pruning/runti
 import { computeEffectiveSettings } from "../pi-extensions/context-pruning/settings.js";
 import { makeToolPrunablePredicate } from "../pi-extensions/context-pruning/tools.js";
 import { ensurePiCompactionReserveTokens } from "../pi-settings.js";
+import { isCacheTtlEligibleProvider, readLastCacheTtlTimestamp } from "./cache-ttl.js";
 
 function resolvePiExtensionPath(id: string): string {
   const self = fileURLToPath(import.meta.url);
@@ -43,7 +44,8 @@ function buildContextPruningExtension(params: {
   model: Model<Api> | undefined;
 }): { additionalExtensionPaths?: string[] } {
   const raw = params.cfg?.agents?.defaults?.contextPruning;
-  if (raw?.mode !== "adaptive" && raw?.mode !== "aggressive") return {};
+  if (raw?.mode !== "cache-ttl") return {};
+  if (!isCacheTtlEligibleProvider(params.provider, params.modelId)) return {};
 
   const settings = computeEffectiveSettings(raw);
   if (!settings) return {};
@@ -52,6 +54,7 @@ function buildContextPruningExtension(params: {
     settings,
     contextWindowTokens: resolveContextWindowTokens(params),
     isToolPrunable: makeToolPrunablePredicate(settings.tools),
+    lastCacheTouchAt: readLastCacheTtlTimestamp(params.sessionManager),
   });
 
   return {

src/agents/pi-embedded-runner/extra-params.ts

@@ -21,7 +21,7 @@ export function resolveExtraParams(params: {
   return modelConfig?.params ? { ...modelConfig.params } : undefined;
 }
 
-type CacheControlTtl = "5m" | "1h";
+type CacheControlTtl = "5m";
 
 function resolveCacheControlTtl(
   extraParams: Record<string, unknown> | undefined,
@@ -29,7 +29,7 @@ function resolveCacheControlTtl(
   modelId: string,
 ): CacheControlTtl | undefined {
   const raw = extraParams?.cacheControlTtl;
-  if (raw !== "5m" && raw !== "1h") return undefined;
+  if (raw !== "5m") return undefined;
   if (provider === "anthropic") return raw;
   if (provider === "openrouter" && modelId.startsWith("anthropic/")) return raw;
   return undefined;

src/agents/pi-embedded-runner/run/attempt.test.ts

@@ -36,8 +36,10 @@ describe("injectHistoryImagesIntoMessages", () => {
     const didMutate = injectHistoryImagesIntoMessages(messages, new Map([[0, [image]]]));
 
     expect(didMutate).toBe(false);
-    const content = messages[0]?.content as unknown[] | undefined;
-    expect(content).toBeDefined();
+    const content = messages[0]?.content;
+    if (!Array.isArray(content)) {
+      throw new Error("expected array content");
+    }
     expect(content).toHaveLength(2);
   });
 

src/agents/pi-embedded-runner/run/attempt.ts

@@ -49,6 +49,7 @@ import { resolveDefaultModelForAgent } from "../../model-selection.js";
 import { isAbortError } from "../abort.js";
 import { buildEmbeddedExtensionPaths } from "../extensions.js";
 import { applyExtraParamsToAgent } from "../extra-params.js";
+import { appendCacheTtlTimestamp, isCacheTtlEligibleProvider } from "../cache-ttl.js";
 import {
   logToolSchemasForGoogle,
   sanitizeSessionHistory,
@@ -685,6 +686,17 @@ export async function runEmbeddedAttempt(
             note: `images: prompt=${imageResult.images.length} history=${imageResult.historyImagesByIndex.size}`,
           });
 
+          const shouldTrackCacheTtl =
+            params.config?.agents?.defaults?.contextPruning?.mode === "cache-ttl" &&
+            isCacheTtlEligibleProvider(params.provider, params.modelId);
+          if (shouldTrackCacheTtl) {
+            appendCacheTtlTimestamp(sessionManager, {
+              timestamp: Date.now(),
+              provider: params.provider,
+              modelId: params.modelId,
+            });
+          }
+
           // Only pass images option if there are actually images to pass
           // This avoids potential issues with models that don't expect the images parameter
           if (imageResult.images.length > 0) {