feat(compaction): add post-compaction recovery turn

After auto-compaction completes, run an agentic turn to help the agent
recover context from memory files and continue any pending work.

Configuration:
- agents.defaults.compaction.postCompaction.enabled (default: true)
- agents.defaults.compaction.postCompaction.prompt
- agents.defaults.compaction.postCompaction.systemPrompt

Default prompt instructs agent to read memory/YYYY-MM-DD.md and reply
with NO_REPLY if nothing requires attention.

Implements #3452

Co-authored-by: Sebastian Almeida <18198367+sebasalmeidam@users.noreply.github.com>

src/auto-reply/reply/agent-runner-memory.ts

@@ -21,6 +21,7 @@ import {
   resolveMemoryFlushSettings,
   shouldRunMemoryFlush,
 } from "./memory-flush.js";
+import { resolvePostCompactionSettings, shouldRunPostCompaction } from "./post-compaction.js";
 import type { FollowupRun } from "./queue.js";
 import { incrementCompactionCount } from "./session-updates.js";
 
@@ -189,5 +190,171 @@ export async function runMemoryFlushIfNeeded(params: {
     logVerbose(`memory flush run failed: ${String(err)}`);
   }
 
+  // Run post-compaction recovery if needed
+  if (memoryCompactionCompleted) {
+    activeSessionEntry =
+      (await runPostCompactionRecoveryIfNeeded({
+        cfg: params.cfg,
+        followupRun: params.followupRun,
+        sessionCtx: params.sessionCtx,
+        opts: params.opts,
+        defaultModel: params.defaultModel,
+        agentCfgContextTokens: params.agentCfgContextTokens,
+        resolvedVerboseLevel: params.resolvedVerboseLevel,
+        sessionEntry: activeSessionEntry,
+        sessionStore: params.sessionStore,
+        sessionKey: params.sessionKey,
+        storePath: params.storePath,
+        isHeartbeat: params.isHeartbeat,
+        memoryCompactionCompleted,
+      })) ?? activeSessionEntry;
+  }
+
+  return activeSessionEntry;
+}
+
+export async function runPostCompactionRecoveryIfNeeded(params: {
+  cfg: MoltbotConfig;
+  followupRun: FollowupRun;
+  sessionCtx: TemplateContext;
+  opts?: GetReplyOptions;
+  defaultModel: string;
+  agentCfgContextTokens?: number;
+  resolvedVerboseLevel: VerboseLevel;
+  sessionEntry?: SessionEntry;
+  sessionStore?: Record<string, SessionEntry>;
+  sessionKey?: string;
+  storePath?: string;
+  isHeartbeat: boolean;
+  memoryCompactionCompleted: boolean;
+}): Promise<SessionEntry | undefined> {
+  const postCompactionSettings = resolvePostCompactionSettings(params.cfg);
+  if (!postCompactionSettings) return params.sessionEntry;
+
+  const postCompactionWritable = (() => {
+    if (!params.sessionKey) return true;
+    const runtime = resolveSandboxRuntimeStatus({
+      cfg: params.cfg,
+      sessionKey: params.sessionKey,
+    });
+    if (!runtime.sandboxed) return true;
+    const sandboxCfg = resolveSandboxConfigForAgent(params.cfg, runtime.agentId);
+    return sandboxCfg.workspaceAccess === "rw";
+  })();
+
+  const shouldRunRecovery =
+    postCompactionSettings &&
+    postCompactionWritable &&
+    !params.isHeartbeat &&
+    !isCliProvider(params.followupRun.run.provider, params.cfg) &&
+    shouldRunPostCompaction({
+      entry:
+        params.sessionEntry ??
+        (params.sessionKey ? params.sessionStore?.[params.sessionKey] : undefined),
+      memoryCompactionCompleted: params.memoryCompactionCompleted,
+    });
+
+  if (!shouldRunRecovery) return params.sessionEntry;
+
+  let activeSessionEntry = params.sessionEntry;
+  const recoveryRunId = crypto.randomUUID();
+  if (params.sessionKey) {
+    registerAgentRunContext(recoveryRunId, {
+      sessionKey: params.sessionKey,
+      verboseLevel: params.resolvedVerboseLevel,
+    });
+  }
+
+  const recoverySystemPrompt = [
+    params.followupRun.run.extraSystemPrompt,
+    postCompactionSettings.systemPrompt,
+  ]
+    .filter(Boolean)
+    .join("\n\n");
+
+  try {
+    await runWithModelFallback({
+      cfg: params.followupRun.run.config,
+      provider: params.followupRun.run.provider,
+      model: params.followupRun.run.model,
+      agentDir: params.followupRun.run.agentDir,
+      fallbacksOverride: resolveAgentModelFallbacksOverride(
+        params.followupRun.run.config,
+        resolveAgentIdFromSessionKey(params.followupRun.run.sessionKey),
+      ),
+      run: (provider, model) => {
+        const authProfileId =
+          provider === params.followupRun.run.provider
+            ? params.followupRun.run.authProfileId
+            : undefined;
+        return runEmbeddedPiAgent({
+          sessionId: params.followupRun.run.sessionId,
+          sessionKey: params.sessionKey,
+          messageProvider: params.sessionCtx.Provider?.trim().toLowerCase() || undefined,
+          agentAccountId: params.sessionCtx.AccountId,
+          messageTo: params.sessionCtx.OriginatingTo ?? params.sessionCtx.To,
+          messageThreadId: params.sessionCtx.MessageThreadId ?? undefined,
+          // Provider threading context for tool auto-injection
+          ...buildThreadingToolContext({
+            sessionCtx: params.sessionCtx,
+            config: params.followupRun.run.config,
+            hasRepliedRef: params.opts?.hasRepliedRef,
+          }),
+          senderId: params.sessionCtx.SenderId?.trim() || undefined,
+          senderName: params.sessionCtx.SenderName?.trim() || undefined,
+          senderUsername: params.sessionCtx.SenderUsername?.trim() || undefined,
+          senderE164: params.sessionCtx.SenderE164?.trim() || undefined,
+          sessionFile: params.followupRun.run.sessionFile,
+          workspaceDir: params.followupRun.run.workspaceDir,
+          agentDir: params.followupRun.run.agentDir,
+          config: params.followupRun.run.config,
+          skillsSnapshot: params.followupRun.run.skillsSnapshot,
+          prompt: postCompactionSettings.prompt,
+          extraSystemPrompt: recoverySystemPrompt,
+          ownerNumbers: params.followupRun.run.ownerNumbers,
+          enforceFinalTag: resolveEnforceFinalTag(params.followupRun.run, provider),
+          provider,
+          model,
+          authProfileId,
+          authProfileIdSource: authProfileId
+            ? params.followupRun.run.authProfileIdSource
+            : undefined,
+          thinkLevel: params.followupRun.run.thinkLevel,
+          verboseLevel: params.followupRun.run.verboseLevel,
+          reasoningLevel: params.followupRun.run.reasoningLevel,
+          execOverrides: params.followupRun.run.execOverrides,
+          bashElevated: params.followupRun.run.bashElevated,
+          timeoutMs: params.followupRun.run.timeoutMs,
+          runId: recoveryRunId,
+        });
+      },
+    });
+
+    const postCompactionCompactionCount =
+      activeSessionEntry?.compactionCount ??
+      (params.sessionKey ? params.sessionStore?.[params.sessionKey]?.compactionCount : 0) ??
+      0;
+
+    if (params.storePath && params.sessionKey) {
+      try {
+        const updatedEntry = await updateSessionStoreEntry({
+          storePath: params.storePath,
+          sessionKey: params.sessionKey,
+          update: async () => ({
+            postCompactionAt: Date.now(),
+            postCompactionCompactionCount,
+          }),
+        });
+        if (updatedEntry) {
+          activeSessionEntry = updatedEntry;
+        }
+      } catch (err) {
+        logVerbose(`failed to persist post-compaction recovery metadata: ${String(err)}`);
+      }
+    }
+  } catch (err) {
+    logVerbose(`post-compaction recovery run failed: ${String(err)}`);
+  }
+
   return activeSessionEntry;
 }

src/auto-reply/reply/post-compaction.test.ts

@@ -0,0 +1,145 @@
+import { describe, expect, it } from "vitest";
+
+import {
+  DEFAULT_POST_COMPACTION_PROMPT,
+  DEFAULT_POST_COMPACTION_SYSTEM_PROMPT,
+  resolvePostCompactionSettings,
+  shouldRunPostCompaction,
+} from "./post-compaction.js";
+
+describe("post-compaction settings", () => {
+  it("defaults to enabled with fallback prompt and system prompt", () => {
+    const settings = resolvePostCompactionSettings();
+    expect(settings).not.toBeNull();
+    expect(settings?.enabled).toBe(true);
+    expect(settings?.prompt.length).toBeGreaterThan(0);
+    expect(settings?.systemPrompt.length).toBeGreaterThan(0);
+  });
+
+  it("respects disable flag", () => {
+    expect(
+      resolvePostCompactionSettings({
+        agents: {
+          defaults: { compaction: { postCompaction: { enabled: false } } },
+        },
+      }),
+    ).toBeNull();
+  });
+
+  it("uses default prompts when not configured", () => {
+    const settings = resolvePostCompactionSettings();
+    expect(settings?.prompt).toContain("Compaction completed");
+    expect(settings?.systemPrompt).toContain("Post-compaction recovery turn");
+  });
+
+  it("appends NO_REPLY hint when missing", () => {
+    const settings = resolvePostCompactionSettings({
+      agents: {
+        defaults: {
+          compaction: {
+            postCompaction: {
+              prompt: "Recovery turn now.",
+              systemPrompt: "Check memory.",
+            },
+          },
+        },
+      },
+    });
+    expect(settings?.prompt).toContain("NO_REPLY");
+    expect(settings?.systemPrompt).toContain("NO_REPLY");
+  });
+
+  it("preserves NO_REPLY hint when already present", () => {
+    const settings = resolvePostCompactionSettings({
+      agents: {
+        defaults: {
+          compaction: {
+            postCompaction: {
+              prompt: "Recovery turn. Reply NO_REPLY if nothing needed.",
+              systemPrompt: "Check memory. Use NO_REPLY when appropriate.",
+            },
+          },
+        },
+      },
+    });
+    // Should not double-append the hint
+    const promptHintCount = (settings?.prompt.match(/NO_REPLY/g) || []).length;
+    const systemHintCount = (settings?.systemPrompt.match(/NO_REPLY/g) || []).length;
+    expect(promptHintCount).toBe(1);
+    expect(systemHintCount).toBe(1);
+  });
+});
+
+describe("shouldRunPostCompaction", () => {
+  it("requires memoryCompactionCompleted to be true", () => {
+    expect(
+      shouldRunPostCompaction({
+        entry: { compactionCount: 1 },
+        memoryCompactionCompleted: false,
+      }),
+    ).toBe(false);
+  });
+
+  it("runs when compaction just completed", () => {
+    expect(
+      shouldRunPostCompaction({
+        entry: { compactionCount: 1 },
+        memoryCompactionCompleted: true,
+      }),
+    ).toBe(true);
+  });
+
+  it("skips when entry is missing but compaction completed", () => {
+    expect(
+      shouldRunPostCompaction({
+        entry: undefined,
+        memoryCompactionCompleted: true,
+      }),
+    ).toBe(true); // Should still run even without entry
+  });
+
+  it("skips when already ran for current compaction count", () => {
+    expect(
+      shouldRunPostCompaction({
+        entry: {
+          compactionCount: 2,
+          postCompactionCompactionCount: 2,
+        },
+        memoryCompactionCompleted: true,
+      }),
+    ).toBe(false);
+  });
+
+  it("runs when compaction count increased since last post-compaction", () => {
+    expect(
+      shouldRunPostCompaction({
+        entry: {
+          compactionCount: 3,
+          postCompactionCompactionCount: 2,
+        },
+        memoryCompactionCompleted: true,
+      }),
+    ).toBe(true);
+  });
+
+  it("runs on first compaction when postCompactionCompactionCount is undefined", () => {
+    expect(
+      shouldRunPostCompaction({
+        entry: {
+          compactionCount: 1,
+        },
+        memoryCompactionCompleted: true,
+      }),
+    ).toBe(true);
+  });
+});
+
+describe("default prompts", () => {
+  it("DEFAULT_POST_COMPACTION_PROMPT includes memory file reference", () => {
+    expect(DEFAULT_POST_COMPACTION_PROMPT).toContain("memory/YYYY-MM-DD.md");
+  });
+
+  it("DEFAULT_POST_COMPACTION_SYSTEM_PROMPT mentions memory files", () => {
+    expect(DEFAULT_POST_COMPACTION_SYSTEM_PROMPT).toContain("memory files");
+  });
+});

src/auto-reply/reply/post-compaction.ts

@@ -0,0 +1,57 @@
+import type { MoltbotConfig } from "../../config/config.js";
+import type { SessionEntry } from "../../config/sessions.js";
+import { SILENT_REPLY_TOKEN } from "../tokens.js";
+
+export const DEFAULT_POST_COMPACTION_PROMPT = [
+  "Compaction completed.",
+  "Read memory/YYYY-MM-DD.md to recover context and continue any pending work.",
+  `Reply with ${SILENT_REPLY_TOKEN} if nothing requires attention.`,
+].join(" ");
+
+export const DEFAULT_POST_COMPACTION_SYSTEM_PROMPT = [
+  "Post-compaction recovery turn.",
+  "Check memory files for recent work context and verify if you were mid-task.",
+].join(" ");
+
+export type PostCompactionSettings = {
+  enabled: boolean;
+  prompt: string;
+  systemPrompt: string;
+};
+
+export function resolvePostCompactionSettings(cfg?: MoltbotConfig): PostCompactionSettings | null {
+  const defaults = cfg?.agents?.defaults?.compaction?.postCompaction;
+  const enabled = defaults?.enabled ?? true;
+  if (!enabled) return null;
+
+  const prompt = defaults?.prompt?.trim() || DEFAULT_POST_COMPACTION_PROMPT;
+  const systemPrompt = defaults?.systemPrompt?.trim() || DEFAULT_POST_COMPACTION_SYSTEM_PROMPT;
+
+  return {
+    enabled,
+    prompt: ensureNoReplyHint(prompt),
+    systemPrompt: ensureNoReplyHint(systemPrompt),
+  };
+}
+
+function ensureNoReplyHint(text: string): string {
+  if (text.includes(SILENT_REPLY_TOKEN)) return text;
+  return `${text}\n\nIf no user-visible reply is needed, start with ${SILENT_REPLY_TOKEN}.`;
+}
+
+export function shouldRunPostCompaction(params: {
+  entry?: Pick<SessionEntry, "compactionCount" | "postCompactionCompactionCount">;
+  memoryCompactionCompleted: boolean;
+}): boolean {
+  if (!params.memoryCompactionCompleted) return false;
+
+  const compactionCount = params.entry?.compactionCount ?? 0;
+  const lastPostCompactionAt = params.entry?.postCompactionCompactionCount;
+
+  // Don't run if we've already run post-compaction for this compaction cycle
+  if (typeof lastPostCompactionAt === "number" && lastPostCompactionAt === compactionCount) {
+    return false;
+  }
+
+  return true;
+}

src/config/schema.ts

@@ -546,6 +546,30 @@ const FIELD_HELP: Record<string, string> = {
     "Minimum appended bytes before session transcripts trigger reindex (default: 100000).",
   "agents.defaults.memorySearch.sync.sessions.deltaMessages":
     "Minimum appended JSONL lines before session transcripts trigger reindex (default: 50).",
+  "agents.defaults.compaction": "Compaction tuning and pre/post-compaction agentic turns.",
+  "agents.defaults.compaction.mode": 'Compaction summarization mode ("default" or "safeguard").',
+  "agents.defaults.compaction.reserveTokensFloor":
+    "Minimum reserve tokens enforced for Pi compaction (0 disables the floor).",
+  "agents.defaults.compaction.maxHistoryShare":
+    "Max share of context window for history during safeguard pruning (0.1–0.9, default 0.5).",
+  "agents.defaults.compaction.memoryFlush":
+    "Pre-compaction memory flush (agentic turn). Default: enabled.",
+  "agents.defaults.compaction.memoryFlush.enabled":
+    "Enable the pre-compaction memory flush (default: true).",
+  "agents.defaults.compaction.memoryFlush.softThresholdTokens":
+    "Run the memory flush when context is within this many tokens of the compaction threshold.",
+  "agents.defaults.compaction.memoryFlush.prompt":
+    "User prompt used for the memory flush turn (NO_REPLY is enforced if missing).",
+  "agents.defaults.compaction.memoryFlush.systemPrompt":
+    "System prompt appended for the memory flush turn.",
+  "agents.defaults.compaction.postCompaction":
+    "Post-compaction recovery turn (agentic turn). Default: enabled.",
+  "agents.defaults.compaction.postCompaction.enabled":
+    "Enable the post-compaction recovery turn (default: true).",
+  "agents.defaults.compaction.postCompaction.prompt":
+    "User prompt used for the post-compaction recovery turn (NO_REPLY is enforced if missing).",
+  "agents.defaults.compaction.postCompaction.systemPrompt":
+    "System prompt appended for the post-compaction recovery turn.",
   "plugins.enabled": "Enable plugin/extension loading (default: true).",
   "plugins.allow": "Optional allowlist of plugin ids; when set, only listed plugins load.",
   "plugins.deny": "Optional denylist of plugin ids; deny wins over allowlist.",

src/config/sessions/types.ts

@@ -77,6 +77,8 @@ export type SessionEntry = {
   compactionCount?: number;
   memoryFlushAt?: number;
   memoryFlushCompactionCount?: number;
+  postCompactionAt?: number;
+  postCompactionCompactionCount?: number;
   cliSessionIds?: Record<string, string>;
   claudeCliSessionId?: string;
   label?: string;

src/config/types.agent-defaults.ts

@@ -248,6 +248,8 @@ export type AgentCompactionConfig = {
   maxHistoryShare?: number;
   /** Pre-compaction memory flush (agentic turn). Default: enabled. */
   memoryFlush?: AgentCompactionMemoryFlushConfig;
+  /** Post-compaction recovery turn (agentic turn). Default: enabled. */
+  postCompaction?: AgentCompactionPostCompactionConfig;
 };
 
 export type AgentCompactionMemoryFlushConfig = {
@@ -260,3 +262,12 @@ export type AgentCompactionMemoryFlushConfig = {
   /** System prompt appended for the memory flush turn. */
   systemPrompt?: string;
 };
+
+export type AgentCompactionPostCompactionConfig = {
+  /** Enable the post-compaction recovery turn (default: true). */
+  enabled?: boolean;
+  /** User prompt used for the post-compaction recovery turn (NO_REPLY is enforced if missing). */
+  prompt?: string;
+  /** System prompt appended for the post-compaction recovery turn. */
+  systemPrompt?: string;
+};

src/config/zod-schema.agent-defaults.ts

@@ -100,6 +100,14 @@ export const AgentDefaultsSchema = z
           })
           .strict()
           .optional(),
+        postCompaction: z
+          .object({
+            enabled: z.boolean().optional(),
+            prompt: z.string().optional(),
+            systemPrompt: z.string().optional(),
+          })
+          .strict()
+          .optional(),
       })
       .strict()
       .optional(),