fix: add usage_events to operational-log retention

usage_events was absent from Database.pruneOperationalLogs, so the
per-tool telemetry log grew unbounded (~187k rows / ~28MB observed) and
became a dominant driver of .fusion DB bloat once runAuditEvents was
already 30-day capped. Prune it on the same operationalLogRetentionDays
cadence, keyed off its `ts` column (not `timestamp`), alongside the other
column-name exceptions. Adds a regression test and changeset.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.changeset/usage-events-retention.md

@@ -0,0 +1,7 @@
+---
+"@runfusion/fusion": patch
+---
+
+summary: Stop the usage telemetry log from growing without bound and bloating the Fusion database.
+category: fix
+dev: usage_events was absent from operational-log retention, so it grew unbounded (observed ~187k rows / ~28MB with nothing ever aged out). pruneOperationalLogs now prunes usage_events on the same operationalLogRetentionDays cadence, keyed off its `ts` column (not `timestamp`). Existing rows still require a one-time VACUUM to reclaim on-disk space.

packages/core/src/__tests__/db.test.ts

@@ -3605,6 +3605,11 @@ describe("Database operational-log retention and recovery-table cleanup", () =>
     ).run(id, agentId, createdAt);
   }
 
+  function insertUsageEvent(ts: string): void {
+    // usage_events.id is INTEGER PRIMARY KEY AUTOINCREMENT — let it auto-assign.
+    db.prepare("INSERT INTO usage_events (ts, kind) VALUES (?, 'tool_call')").run(ts);
+  }
+
   it("pruneOperationalLogs deletes rows older than the retention window", () => {
     const old = new Date(Date.now() - 200 * 86_400_000).toISOString();
     const recent = new Date(Date.now() - 1 * 86_400_000).toISOString();
@@ -3675,8 +3680,27 @@ describe("Database operational-log retention and recovery-table cleanup", () =>
     expect(remaining.map((row) => row.id)).toEqual(["agent-1-recent", "agent-2-old-2"]);
   });
 
+  it("pruneOperationalLogs deletes old usage_events by their `ts` column but keeps recent ones", () => {
+    // FNXC:TelemetryRetention 2026-07-08-00:00:
+    // Regression guard for the unbounded-growth fix: usage_events must age out on
+    // the same retention cadence as the other operational logs, keyed off its `ts`
+    // column (not `timestamp`), which is why it needs its own delete path.
+    const old = new Date(Date.now() - 200 * 86_400_000).toISOString();
+    const recent = new Date(Date.now() - 1 * 86_400_000).toISOString();
+    insertUsageEvent(old);
+    insertUsageEvent(old);
+    insertUsageEvent(recent);
+
+    const result = db.pruneOperationalLogs(90 * 86_400_000);
+    expect(result.deletedByTable.usage_events).toBe(2);
+
+    const remaining = db.prepare("SELECT ts FROM usage_events").all() as Array<{ ts: string }>;
+    expect(remaining).toEqual([{ ts: recent }]);
+  });
+
   it("pruneOperationalLogs is a no-op when retention is disabled (<= 0)", () => {
     insertActivity("old-1", new Date(Date.now() - 200 * 86_400_000).toISOString());
+    insertUsageEvent(new Date(Date.now() - 200 * 86_400_000).toISOString());
     insertAgent("agent-1");
     insertAgentRun({
       id: "run-old-completed",
@@ -3694,6 +3718,7 @@ describe("Database operational-log retention and recovery-table cleanup", () =>
     const result = db.pruneOperationalLogs(0);
     expect(result.deletedTotal).toBe(0);
     expect(db.prepare("SELECT count(*) AS c FROM activityLog").get()).toMatchObject({ c: 1 });
+    expect(db.prepare("SELECT count(*) AS c FROM usage_events").get()).toMatchObject({ c: 1 });
     expect(db.prepare("SELECT count(*) AS c FROM agentRuns").get()).toMatchObject({ c: 1 });
     expect(db.prepare("SELECT count(*) AS c FROM agentConfigRevisions").get()).toMatchObject({ c: 1 });
   });

packages/core/src/db.ts

@@ -2581,6 +2581,22 @@ export class Database {
       }
     }
 
+    /*
+     * FNXC:TelemetryRetention 2026-07-08-00:00:
+     * usage_events is an append-only per-tool telemetry log. Unlike the OPERATIONAL_LOG_TABLES set it originally had NO retention, so it grew unbounded and became the dominant driver of .fusion DB bloat once runAuditEvents was already 30-day capped (observed ~187k rows / ~28MB with no aged-out rows because nothing ever deleted them).
+     * Prune it on the same operationalLogRetentionDays cadence as the other operational logs. Its timestamp column is `ts` (not `timestamp`), so it cannot join the generic OPERATIONAL_LOG_TABLES loop above and gets its own delete here alongside the other column-name exceptions (agentRuns.endedAt, agentConfigRevisions.createdAt).
+     */
+    if (this.tableExists("usage_events")) {
+      try {
+        recordChanges(
+          "usage_events",
+          this.db.prepare("DELETE FROM usage_events WHERE ts < ?").run(cutoffIso),
+        );
+      } catch (error) {
+        console.warn("[fusion:db] Failed to prune operational log table usage_events", error);
+      }
+    }
+
     return { deletedByTable, deletedTotal };
   }