diff --git a/packages/bus/src/proxy-usage.mjs b/packages/bus/src/proxy-usage.mjs
index acebef5c3..bc5dec49b 100644
--- a/packages/bus/src/proxy-usage.mjs
+++ b/packages/bus/src/proxy-usage.mjs
@@ -12,6 +12,9 @@ export function createProxyUsage({ store, read, client, records, log, now = Date
   const loader = makeLoader({ log });
   let due = 0, previous = '', pending = null, closed = false;
   const states = new Map();
+  // #778: per enabled business, the batches taken off the proxy queue and then not written, since
+  // this bus started. Telemetry only: the events in a dropped batch are gone and no quota reads this.
+  const dropped = new Map();
   function configured() {
     return Object.entries(read()).filter(([, b]) => b.plugins?.usage === 'cliproxy-queue').map(([business, b]) => {
       checkUsageSettings(b.usage ?? {});
@@ -27,13 +30,22 @@ export function createProxyUsage({ store, read, client, records, log, now = Date
     if (signature !== previous) { previous = signature; due = 0; }
     if (now() < due) return;
     due = now() + Math.min(...enabled.map(b => b.pollSeconds)) * 1000;
+    // drained: the proxy has given this batch up, because module.read returned or because the client
+    // refused a 2xx answer it had already taken (proxy-client-response). Down, redirected or non-2xx
+    // answers drained nothing. written: the rows are in.
+    let drained = false, written = false;
     try {
       await loader.load({ usage: 'cliproxy-queue' });
       const module = loader.modules('usage')[0], management = await client();
       if (!module || !management) throw Error('unavailable');
       // Row 333 R3 (#1831): the module gets the one read it needs and nothing else. No path from
       // its argument reaches getKeys, putKeys, the OAuth calls or any other management call.
-      const events = await module.read(Object.freeze({ readUsageQueue: () => management.readUsageQueue() }));
+      const readUsageQueue = async () => {
+        try { return await management.readUsageQueue(); }
+        catch (error) { if (error?.code === 'proxy-client-response') drained = true; throw error; }
+      };
+      const events = await module.read(Object.freeze({ readUsageQueue }));
+      drained = true;
       const owners = new Map();
       for (const record of records()) {
         if (record.service !== 'model') continue;
@@ -64,10 +76,14 @@ export function createProxyUsage({ store, read, client, records, log, now = Date
             JSON.stringify({ modelKeyId: e.keyId, failed: e.failed, statusCode: e.statusCode }), e.input, e.output, e.cacheWrite, e.cacheRead);
         }
       });
+      written = true;
       for (const keyId of unknown) log({ action: 'proxy.usage.reconcile', keyId, code: 'proxy-usage-unknown-key' });
       for (const { business } of enabled) states.set(business, 'available');
     } catch {
-      for (const { business } of enabled) states.set(business, 'unavailable');
+      for (const { business } of enabled) {
+        states.set(business, 'unavailable');
+        if (drained && !written) dropped.set(business, (dropped.get(business) ?? 0) + 1);
+      }
       log({ action: 'proxy.usage', code: 'proxy-usage-read-failed' });
     }
   }
@@ -92,7 +108,7 @@ export function createProxyUsage({ store, read, client, records, log, now = Date
       }
     }
     const finish = map => [...map.values()].map(e => ({ ...e, ...Object.fromEntries(KINDS.map(k => [k, plain(e[k])])) }));
-    return { source: 'proxy', state: states.get(business) ?? 'unread', byKey: finish(byKey), byAccount: finish(byAccount) };
+    return { source: 'proxy', state: states.get(business) ?? 'unread', droppedBatches: dropped.get(business) ?? 0, byKey: finish(byKey), byAccount: finish(byAccount) };
   }
   return { tick, view, async close() { closed = true; await pending; } };
 }
diff --git a/packages/bus/tests/proxy-usage.test.mjs b/packages/bus/tests/proxy-usage.test.mjs
index ddffa2406..2b0988a7d 100644
--- a/packages/bus/tests/proxy-usage.test.mjs
+++ b/packages/bus/tests/proxy-usage.test.mjs
@@ -15,15 +15,15 @@ const id = s => createHash('sha256').update(s).digest('hex').slice(0,12);
 const key='msk-fake-client-value',source='fake-upstream-value',keyId=id(key);
 async function fixture(t,{makeLoader}={}) {
  const root=mkdtempSync(join(tmpdir(),'proxy-usage-')),store=new Store(root),logs=[],calls=[];
- let events=[],now=0,fail=false;
+ let events=[],now=0,fail=false,noClient=false,recs=[{instance:'demo/coder',service:'model',keyId,retiring:[]}];
  const server=http.createServer((req,res)=>{calls.push(req.url);res.writeHead(fail?500:200);res.end(JSON.stringify(events));events=[];});
  await new Promise(r=>server.listen(0,'127.0.0.1',r));
  const client=new ManagementClient({baseUrl:`http://127.0.0.1:${server.address().port}`,key:'fake-management',receipt:e=>logs.push(e)});
  let doc={plugins:{},launch:{limits:{tokens:{keys:{[keyId]:{limit:1,since:'2026-01-01T00:00:00.000Z'}}}}}};
- const reader=createProxyUsage({store,read:()=>({demo:doc}),client:()=>client,...(makeLoader?{makeLoader}:{}),records:()=>[{instance:'demo/coder',service:'model',keyId,retiring:[]}],log:e=>logs.push(e),now:()=>now});
+ const reader=createProxyUsage({store,read:()=>({demo:doc}),client:()=>noClient?null:client,...(makeLoader?{makeLoader}:{}),records:()=>recs,log:e=>logs.push(e),now:()=>now});
  t.after(async()=>{await reader.close();await new Promise(r=>server.close(r));store.close();rmSync(root,{recursive:true,force:true});});
  const event=(over={})=>({api_key:key,source,failed:true,fail:{status_code:503,body:source},tokens:{input_tokens:9,output_tokens:2},...over});
- return {store,logs,calls,reader,client,event,setEvents:v=>{events=v;},clock:v=>{now=v;},enable:(pollSeconds)=>{doc={...doc,plugins:{usage:'cliproxy-queue','limit-check':['token-limit']},...(pollSeconds===undefined?{}:{usage:{cliproxyQueue:{pollSeconds}}})};},doc:()=>doc,fail:()=>{fail=true;}};
+ return {store,logs,calls,reader,client,event,setEvents:v=>{events=v;},clock:v=>{now=v;},enable:(pollSeconds)=>{doc={...doc,plugins:{usage:'cliproxy-queue','limit-check':['token-limit']},...(pollSeconds===undefined?{}:{usage:{cliproxyQueue:{pollSeconds}}})};},doc:()=>doc,fail:()=>{fail=true;},noClient:v=>{noClient=v;},setRecords:v=>{recs=v;}};
 }
 test('P5 usage plugin off by default, default poll is 15 seconds and configured polls skip early ticks',async t=>{
  const f=await fixture(t);await f.reader.tick();assert.equal(f.calls.length,0);assert.equal(f.reader.view('demo'),null);
@@ -109,3 +109,49 @@ test('R3 the usage module is handed one function, readUsageQueue, and no path to
  assert.deepEqual(called,['readUsageQueue']);
  assert.equal(f.reader.view('demo').byKey[0].failures,1);
 });
+
+// #778 (Vikunja): the queue read drains the proxy, so a batch that is then not written is lost. The count
+// is per enabled business, in memory since the bus started, and telemetry only.
+test('#778 a drained batch that is not written counts as dropped; a poll that drained nothing does not; a good poll keeps the count',async t=>{
+ const f=await fixture(t);f.enable();
+ const usage=await createUsage({store:f.store,businesses:{demo:f.doc()},log:()=>{},proxyView:b=>f.reader.view(b)});
+ assert.equal(f.reader.view('demo').droppedBatches,0);
+ // An invalid batch: the client refuses the 2xx answer whole, and the proxy has already given the batch up.
+ f.setEvents([f.event(),f.event({source:'malformed-upstream-canary',tokens:{input_tokens:-1}})]);await f.reader.tick();
+ assert.equal(f.reader.view('demo').droppedBatches,1);assert.equal(f.reader.view('demo').state,'unavailable');
+ // An ambiguous owner: one key id held by two agents.
+ f.setRecords([{instance:'demo/coder',service:'model',keyId,retiring:[]},{instance:'demo/other',service:'model',keyId,retiring:[]}]);
+ f.setEvents([f.event()]);f.clock(15000);await f.reader.tick();
+ assert.equal(f.reader.view('demo').droppedBatches,2);
+ // No client before the read: nothing was drained, so nothing was dropped.
+ f.noClient(true);f.setEvents([f.event()]);f.clock(30000);await f.reader.tick();
+ assert.equal(f.reader.view('demo').droppedBatches,2);assert.equal(f.reader.view('demo').state,'unavailable');
+ // A good poll sets the state back and leaves the count alone. The event set while the client was missing is still queued.
+ f.noClient(false);f.setRecords([{instance:'demo/coder',service:'model',keyId,retiring:[]}]);f.clock(45000);await f.reader.tick();
+ assert.equal(f.reader.view('demo').state,'available');assert.equal(f.reader.view('demo').droppedBatches,2);
+ assert.equal(f.reader.view('demo').byKey[0].requests,1);
+ // The usage view carries it, and a log line names no event content.
+ assert.equal(usage.view('demo').proxy.droppedBatches,2);
+ for(const secret of [key,source,'malformed-upstream-canary'])assert.equal(JSON.stringify([f.logs,usage.view('demo')]).includes(secret),false);
+ assert.deepEqual(f.logs.filter(e=>e.action==='proxy.usage').map(e=>e.code),['proxy-usage-read-failed','proxy-usage-read-failed','proxy-usage-read-failed']);
+});
+test('#778 a batch the module returns in a shape the bus refuses is a drop',async t=>{
+ const makeLoader=opts=>{const loader=createLoader(opts);return {...loader,modules:kind=>loader.modules(kind).map(m=>kind==='usage'&&m?{interfaceVersion:m.interfaceVersion,read:async arg=>{await arg.readUsageQueue();return [{keyId:'not-a-key-id',accountId:id(source)}];}}:m)};};
+ const f=await fixture(t,{makeLoader});f.enable();f.setEvents([f.event()]);await f.reader.tick();
+ assert.equal(f.reader.view('demo').state,'unavailable');assert.equal(f.reader.view('demo').droppedBatches,1);
+ assert.equal(f.store.all('SELECT * FROM usage_records').length,0);
+});
+test('#778 a read the proxy refused or never answered drained nothing and is not a drop',async t=>{
+ const f=await fixture(t);f.enable();f.fail();await f.reader.tick();
+ assert.equal(f.reader.view('demo').state,'unavailable');assert.equal(f.reader.view('demo').droppedBatches,0);
+});
+test('#778 a failed transaction drops the batch for every enabled business',async t=>{
+ const f=await fixture(t);f.enable();
+ const broken={all:(...a)=>f.store.all(...a),run:(...a)=>f.store.run(...a),transaction:()=>{throw new Error('disk full');}};
+ const both={demo:f.doc(),other:f.doc()};
+ const reader=createProxyUsage({store:broken,read:()=>both,client:()=>f.client,records:()=>[{instance:'demo/coder',service:'model',keyId,retiring:[]}],log:e=>f.logs.push(e),now:()=>0});
+ t.after(()=>reader.close());
+ f.setEvents([f.event()]);await reader.tick();
+ for(const business of ['demo','other']){assert.equal(reader.view(business).droppedBatches,1);assert.equal(reader.view(business).state,'unavailable');}
+ assert.equal(f.store.all('SELECT * FROM usage_records').length,0);
+});
diff --git a/packages/plugins/usage/cliproxy-queue/README.md b/packages/plugins/usage/cliproxy-queue/README.md
index db3938c7c..88b1db1af 100644
--- a/packages/plugins/usage/cliproxy-queue/README.md
+++ b/packages/plugins/usage/cliproxy-queue/README.md
@@ -30,7 +30,14 @@ Telemetry uses the existing append-only usage table with source
 excludes it before every limit check and native usage total. Proxy totals may be
 incomplete (60-second upstream retention and a 100-event drain); the Console
 labels them proxy-reported and reports the reader's availability. They never
-independently enforce quotas.
+independently enforce quotas. A batch the proxy has already given up and the
+bus then does not save (the client refuses its answer, the bus refuses its
+shape or an ambiguous key owner, or the write fails) is lost. The reader counts
+these per business since the bus started and the usage view returns the count
+as `droppedBatches` (0 when none); the Console shows it above 0. A read that
+failed before the proxy answered, or that the proxy refused, drained nothing
+and is not counted. The count is in memory, restarts at 0 and is not a quota
+input.
 
 Native transcript counts carry the immutable run's safe `modelKeyId` in the
 usage cursor, preserved at turn begin and end. The Console exposes `byKey`.
diff --git a/packages/webui/src/public/bus.js b/packages/webui/src/public/bus.js
index f7dd6248d..70b275b62 100644
--- a/packages/webui/src/public/bus.js
+++ b/packages/webui/src/public/bus.js
@@ -759,7 +759,10 @@
     }
     // Row 333 R3 (#1831): a daily key quota whose key id no hired agent holds, now or before.
     const orphans = Array.isArray(value.orphanedKeyQuotas) && value.orphanedKeyQuotas.length ? `<ul id="token-usage-orphans" aria-label="Key quotas that match no agent">${value.orphanedKeyQuotas.map(id => `<li>Key quota ${txt(id)} matches no agent, so it limits nothing. A fire and re-hire gives the agent a new key; set the quota on the new key id.</li>`).join('')}</ul>` : '';
-    const proxy = value.proxy ? `<section aria-label="Proxy-reported usage"><h3>Proxy-reported usage</h3><p>Optional proxy telemetry never enforces a quota. Status: ${txt(value.proxy.state)}. These counts cover drained events and may be incomplete.</p><div class="table-wrap"><table><thead><tr><th>Proxy account ID</th><th>Input</th><th>Output</th><th>Cache write</th><th>Cache read</th><th>Requests</th><th>Failures</th></tr></thead><tbody>${(value.proxy.byAccount || []).map(row => `<tr><th scope="row">${txt(row.accountId)}</th>${['input','output','cacheWrite','cacheRead','requests','failures'].map(k => `<td>${txt(row[k])}</td>`).join('')}</tr>`).join('')}</tbody></table></div></section>` : '';
+    // #778: batches the proxy gave up and the bus did not save, since the bus started. Shown only above 0.
+    const lost = Number.isSafeInteger(value.proxy?.droppedBatches) ? value.proxy.droppedBatches : 0;
+    const dropped = lost > 0 ? `<p id="token-usage-proxy-dropped" role="status">${txt(lost)} ${lost === 1 ? 'batch' : 'batches'} of proxy usage events could not be saved since the bus started. The events in a dropped batch are lost and are not in these totals.</p>` : '';
+    const proxy = value.proxy ? `<section aria-label="Proxy-reported usage"><h3>Proxy-reported usage</h3><p>Optional proxy telemetry never enforces a quota. Status: ${txt(value.proxy.state)}. These counts cover drained events and may be incomplete.</p>${dropped}<div class="table-wrap"><table><thead><tr><th>Proxy account ID</th><th>Input</th><th>Output</th><th>Cache write</th><th>Cache read</th><th>Requests</th><th>Failures</th></tr></thead><tbody>${(value.proxy.byAccount || []).map(row => `<tr><th scope="row">${txt(row.accountId)}</th>${['input','output','cacheWrite','cacheRead','requests','failures'].map(k => `<td>${txt(row[k])}</td>`).join('')}</tr>`).join('')}</tbody></table></div></section>` : '';
     return `<section class="panel" aria-labelledby="token-usage-title"><h2 id="token-usage-title">Token usage</h2><p>Best reading of session-editable transcripts, not proof. Unknown turns may have used more tokens. Account is unassigned until account tracking is configured.</p><div class="table-wrap"><table id="token-usage-table"><thead><tr><th scope="col">Subject</th><th scope="col">Input</th><th scope="col">Output</th><th scope="col">Cache write</th><th scope="col">Cache read</th><th scope="col">Unknown turns</th></tr></thead><tbody>${rows.join('')}</tbody></table></div>${orphans}${proxy}</section>`;
   }
   // Row 155 (#1649, Q169): each assistant instance's settings, its seat name and a stop. A save
diff --git a/packages/webui/tests/usage-render.test.mjs b/packages/webui/tests/usage-render.test.mjs
index ed0b159c9..1b10f86d4 100644
--- a/packages/webui/tests/usage-render.test.mjs
+++ b/packages/webui/tests/usage-render.test.mjs
@@ -28,3 +28,15 @@ test('R3 Console marks an orphaned key quota by id and says it limits nothing',(
  const hostile=render({total:counts,byKey:[],orphanedKeyQuotas:['<img src=x>']});
  assert.doesNotMatch(hostile,/<img/);assert.match(hostile,/&lt;img src=x&gt;/);
 });
+// #778: batches the proxy gave up and the bus did not save. Shown in the proxy section only when above 0.
+test('#778 Console says how many proxy batches were dropped, only when there are any, and that their events are not in the totals',()=>{
+ const native={total:counts,byKey:[]},proxy=(over={})=>({source:'proxy',state:'available',byAccount:[],...over});
+ const one=render({...native,proxy:proxy({droppedBatches:1})});
+ assert.match(one,/<p id="token-usage-proxy-dropped" role="status">1 batch of proxy usage events could not be saved since the bus started\. The events in a dropped batch are lost and are not in these totals\.<\/p>/);
+ assert.ok(one.indexOf('token-usage-proxy-dropped')>one.indexOf('Proxy-reported usage'));
+ assert.match(render({...native,proxy:proxy({droppedBatches:3})}),/>3 batches of proxy usage events could not be saved/);
+ for(const over of [{droppedBatches:0},{},{droppedBatches:-1},{droppedBatches:'2'},{droppedBatches:1.5},{droppedBatches:null}]){
+  const page=render({...native,proxy:proxy(over)});assert.match(page,/Proxy-reported/);assert.doesNotMatch(page,/token-usage-proxy-dropped|dropped batch/);
+ }
+ assert.doesNotMatch(render({...native,proxy:null}),/token-usage-proxy-dropped/);
+});