fix(FN-4388): tighten cache-stats ephemeral filtering and tests

Fusion-Task-Id: FN-4388
Fusion-Task-Lineage: 7497a0a1-5edb-4778-b339-118d1fd668f7

scripts/__tests__/cache-stats.test.mjs

@@ -1,6 +1,6 @@
 import test from "node:test";
 import assert from "node:assert/strict";
-import { collectCacheStats } from "../cache-stats.mjs";
+import { collectCacheStats, main } from "../cache-stats.mjs";
 
 test("collectCacheStats groups role and permanent-agent totals", async () => {
   const taskStore = {
@@ -21,7 +21,11 @@ test("collectCacheStats groups role and permanent-agent totals", async () => {
     },
   };
 
-  const result = await collectCacheStats({ taskStore, agentStore });
+  const result = await collectCacheStats({
+    taskStore,
+    agentStore,
+    isEphemeralAgent: (agent) => agent.metadata?.type === "spawned" || agent.metadata?.agentKind === "task-worker",
+  });
 
   assert.equal(result.byRole.find((r) => r.role === "executor")?.total_cached, 50);
   assert.equal(result.byRole.find((r) => r.role === "reviewer")?.total_input, 200);
@@ -30,3 +34,33 @@ test("collectCacheStats groups role and permanent-agent totals", async () => {
   assert.equal(result.byAgent[0].id, "a1");
   assert.equal(result.byAgent[0].hit_ratio, 50 / 150);
 });
+
+test("collectCacheStats handles empty and zero-token datasets", async () => {
+  const taskStore = { async listTasks() { return [{ assignedAgentId: "a1" }, { assignedAgentId: "a1", tokenUsage: { inputTokens: 0, cachedTokens: 0, cacheWriteTokens: 0, outputTokens: 0 } }]; } };
+  const agentStore = { async listAgents() { return [{ id: "a1", role: "executor", metadata: { type: "permanent" } }]; } };
+
+  const result = await collectCacheStats({ taskStore, agentStore, isEphemeralAgent: () => false });
+  assert.equal(result.byRole.length, 1);
+  assert.equal(result.byRole[0].hit_ratio, 0);
+  assert.equal(result.byAgent[0].n_tasks, 1);
+});
+
+test("main --json prints machine-readable output", async () => {
+  const logs = [];
+  const originalLog = console.log;
+  console.log = (value) => logs.push(String(value));
+  try {
+    const code = await main(["--json"], {
+      stores: {
+        taskStore: { async listTasks() { return []; } },
+        agentStore: { async listAgents() { return []; } },
+        isEphemeralAgent: () => false,
+      },
+    });
+    assert.equal(code, 0);
+    const parsed = JSON.parse(logs[0]);
+    assert.deepEqual(parsed, { byRole: [], byAgent: [] });
+  } finally {
+    console.log = originalLog;
+  }
+});

scripts/cache-stats.mjs

@@ -22,7 +22,7 @@ function printTable(title, rows) {
   console.table(rows);
 }
 
-export async function collectCacheStats({ taskStore, agentStore }) {
+export async function collectCacheStats({ taskStore, agentStore, isEphemeralAgent = () => false }) {
   const tasks = await taskStore.listTasks({ includeArchived: true, slim: true });
   const agents = await agentStore.listAgents({ includeEphemeral: true });
   const agentById = new Map(agents.map((agent) => [agent.id, agent]));
@@ -39,7 +39,7 @@ export async function collectCacheStats({ taskStore, agentStore }) {
     if (!roleSummaries.has(role)) roleSummaries.set(role, createSummary());
     applyUsage(roleSummaries.get(role), task.tokenUsage);
 
-    if (owner && owner.metadata?.type !== "spawned") {
+    if (owner && !isEphemeralAgent(owner)) {
       if (!agentSummaries.has(owner.id)) agentSummaries.set(owner.id, { id: owner.id, role: owner.role, ...createSummary() });
       applyUsage(agentSummaries.get(owner.id), task.tokenUsage);
     }
@@ -54,16 +54,16 @@ export async function main(argv = process.argv.slice(2), deps = {}) {
   const asJson = argv.includes("--json");
   const projectDir = process.cwd();
 
-  const { taskStore, agentStore } = deps.stores ?? (await (async () => {
-    const { TaskStore, AgentStore } = await import("../packages/core/dist/index.js");
+  const { taskStore, agentStore, isEphemeralAgent } = deps.stores ?? (await (async () => {
+    const { TaskStore, AgentStore, isEphemeralAgent } = await import("../packages/core/dist/index.js");
     const store = new TaskStore(projectDir);
     await store.init();
     const aStore = new AgentStore({ rootDir: store.getFusionDir() });
     await aStore.init();
-    return { taskStore: store, agentStore: aStore };
+    return { taskStore: store, agentStore: aStore, isEphemeralAgent };
   })());
 
-  const result = await collectCacheStats({ taskStore, agentStore });
+  const result = await collectCacheStats({ taskStore, agentStore, isEphemeralAgent });
   if (asJson) {
     console.log(JSON.stringify(result, null, 2));
     return 0;