diff --git a/web/react/src/App.tsx b/web/react/src/App.tsx
index 607ce71..61ca0f0 100644
--- a/web/react/src/App.tsx
+++ b/web/react/src/App.tsx
@@ -239,6 +239,9 @@ export function App() {
       .then(() => dispatch("PROGRAM_RUN", {}, false))
       .catch(() => undefined);
   };
+  const clearLoadedPreview = async () => {
+    await operationController.execute("VISUAL_CLEAR", {}, { state: axisState, gate: false });
+  };
   const loadCase = async () => {
     if (programLoading || programRunning) return;
     setProgramLoading(true);
@@ -256,6 +259,7 @@ export function App() {
       const operation = await operationController.execute("LOAD_WORKSPACE", { root_path: "/workspace", configuration: toWorkerConfiguration(bundle) }, { state: axisState, gate: false });
       const resultPayload = (operation.response as { payload?: { configuration?: { state?: string } } }).payload;
       setProgramText(normalizedSource); setProgramPath(PROGRAM_PATH); setPlotCleared(false);
+      await clearLoadedPreview();
       await operationController.execute("PROGRAM_LOAD", { source: normalizedSource, path: PROGRAM_PATH }, { state: axisState, gate: false });
       setOperationTrace(operationController.exportTrace());
       setCommandStatus("PROGRAM_LOAD acknowledged");
@@ -277,6 +281,7 @@ export function App() {
       const source = normalizeProgramSource(await response.text());
       if (!source.trim()) throw new Error("program_asset_empty");
       setProgramText(source); setProgramPath(path); setPlotCleared(false);
+      await clearLoadedPreview();
       await operationController.execute("PROGRAM_LOAD", { source, path }, { state: axisState, gate: false });
       setOperationTrace(operationController.exportTrace());
       setCommandStatus("PROGRAM_LOAD acknowledged");
@@ -291,7 +296,7 @@ export function App() {
     setProgramLoading(true);
     setCommandStatus("PROGRAM_LOAD pending: waiting for LinuxCNC WASM preview");
     setPlotCleared(false);
-    void dispatch("PROGRAM_LOAD", { source: programText, path: programPath })
+    void clearLoadedPreview().then(() => dispatch("PROGRAM_LOAD", { source: programText, path: programPath }))
       .then(() => setCaseStatus(`${programPath} loaded through linuxcnc-wasm`))
       .catch(() => undefined)
       .finally(() => setProgramLoading(false));
diff --git a/web/worker/operation-ledger.mjs b/web/worker/operation-ledger.mjs
index 2824ea3..be4e3a3 100644
--- a/web/worker/operation-ledger.mjs
+++ b/web/worker/operation-ledger.mjs
@@ -56,7 +56,13 @@ export class OperationLedger {
     entry.phase = "verified";
     entry.status = response?.payload?.status === "error" || response?.kind === "ERROR" ? "failed" : "verified";
     entry.result_hash = fnv1a64(response?.payload ?? {});
-    entry.response = clone(response);
+    const payload = response?.payload;
+    // High-frequency fixed-tick responses are deltas. Keep only the compact
+    // operation evidence in the ledger; the full delta is already delivered
+    // to the client and retained by the frontend trace window.
+    entry.response = payload?.snapshot_mode === "motion_delta"
+      ? { ...response, payload: { status: payload.status, snapshot_mode: payload.snapshot_mode, simulation_tick: response.simulation_tick ?? null, program: payload.program ? { current_line: payload.program.current_line, program_status: payload.program.program_status, state_hash: payload.program.state_hash } : null } }
+      : clone(response);
     return clone(entry);
   }
 
diff --git a/web/worker/xyzac-command-ledger.mjs b/web/worker/xyzac-command-ledger.mjs
index 321856b..625026c 100644
--- a/web/worker/xyzac-command-ledger.mjs
+++ b/web/worker/xyzac-command-ledger.mjs
@@ -45,11 +45,13 @@ export class XyzacCommandLedger extends OperationLedger {
     return { status: "reconcile_required", operation_id: operationId, retry_allowed: false, reconciliation };
   }
 
-  audit({ includeResponses = true } = {}) {
+  audit({ includeResponses = true, maxEntries = Number.POSITIVE_INFINITY } = {}) {
     const exported = super.export();
     const pending = this.pending();
-    const entries = includeResponses ? exported.entries : exported.entries.map((entry) => { const { response, ...summary } = entry; return summary; });
-    const unsigned = { schema: XYZAC_COMMAND_LEDGER_SCHEMA, operation_schema: LEDGER_SCHEMA, phases: [...LEDGER_PHASES], scope: this.scope, entries, pending_count: pending.length };
+    const totalEntries = exported.entries.length;
+    const windowed = Number.isFinite(maxEntries) && maxEntries >= 0 ? exported.entries.slice(-Math.floor(maxEntries)) : exported.entries;
+    const entries = includeResponses ? windowed : windowed.map((entry) => { const { response, ...summary } = entry; return summary; });
+    const unsigned = { schema: XYZAC_COMMAND_LEDGER_SCHEMA, operation_schema: LEDGER_SCHEMA, phases: [...LEDGER_PHASES], scope: this.scope, entries, entry_count: totalEntries, truncated: entries.length < totalEntries, pending_count: pending.length };
     return { ...unsigned, state_hash: fnv1a64(unsigned) };
   }
 }
diff --git a/web/worker/xyzac-session.mjs b/web/worker/xyzac-session.mjs
index 7ad8cbd..32edbdc 100644
--- a/web/worker/xyzac-session.mjs
+++ b/web/worker/xyzac-session.mjs
@@ -34,7 +34,7 @@ export class XyzacSession extends SimSession {
     // every previous response inside the stored response object.
     const payload = { ...response.payload };
     payload.xyzac_session = this.authority();
-    payload.xyzac_ledger = this.ledger.audit({ includeResponses: input.kind !== "SIM_STEP" });
+    payload.xyzac_ledger = this.ledger.audit({ includeResponses: input.kind !== "SIM_STEP", maxEntries: input.kind === "SIM_STEP" ? 32 : 2048 });
     payload.xyzac_scheduler = this.scheduler.export();
     return { ...response, payload };
   }