diff --git a/static/index.html b/static/index.html
index c8a3ad5..1c34558 100644
--- a/static/index.html
+++ b/static/index.html
@@ -264,6 +264,10 @@
               </svg>
             </button>
           </div>
+          <div class="ctx-indicator" id="ctxIndicator" style="display:none" title="Context window usage">
+            <span class="ctx-bar-wrap"><span class="ctx-bar" id="ctxBar"></span></span>
+            <span class="ctx-label" id="ctxLabel"></span>
+          </div>
           <div class="composer-right">
             <button class="send-btn" id="btnSend" title="Send message" style="display:none">
               <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.5" stroke-linecap="round" stroke-linejoin="round"><line x1="12" y1="19" x2="12" y2="5"/><polyline points="5 12 12 5 19 12"/></svg>
diff --git a/static/messages.js b/static/messages.js
index 9b76152..35cf27f 100644
--- a/static/messages.js
+++ b/static/messages.js
@@ -160,7 +160,7 @@ async function send(){
         // Stamp _ts on the last assistant message if it has no timestamp
         const lastAsst=[...S.messages].reverse().find(m=>m.role==='assistant');
         if(lastAsst&&!lastAsst._ts&&!lastAsst.timestamp) lastAsst._ts=Date.now()/1000;
-        if(d.usage) S.lastUsage=d.usage;
+        if(d.usage){S.lastUsage=d.usage;_syncCtxIndicator(d.usage);}
         if(d.session.tool_calls&&d.session.tool_calls.length){
           S.toolCalls=d.session.tool_calls.map(tc=>({...tc,done:true}));
         } else {
diff --git a/static/style.css b/static/style.css
index bbddcf6..f6d0afb 100644
--- a/static/style.css
+++ b/static/style.css
@@ -189,6 +189,13 @@
   textarea#msg::placeholder{color:var(--muted);}
   .composer-footer{display:flex;align-items:center;justify-content:space-between;padding:6px 10px 10px;}
   .composer-left{display:flex;gap:2px;align-items:center;}
+  /* Context usage indicator */
+  .ctx-indicator{display:flex;align-items:center;gap:6px;padding:2px 4px;flex-shrink:1;min-width:0;}
+  .ctx-bar-wrap{width:70px;height:5px;border-radius:3px;background:rgba(255,255,255,.08);overflow:hidden;flex-shrink:0;}
+  .ctx-bar{display:block;height:100%;border-radius:3px;transition:width .4s ease,background .4s ease;min-width:2px;background:var(--teal);}
+  .ctx-bar.ctx-mid{background:#e6a817;}
+  .ctx-bar.ctx-high{background:#e05252;}
+  .ctx-label{font-size:9px;color:var(--muted);white-space:nowrap;font-variant-numeric:tabular-nums;}
   .composer-right{display:flex;gap:6px;align-items:center;}
   .icon-btn{width:34px;height:34px;border-radius:8px;background:none;border:none;color:var(--muted);cursor:pointer;display:flex;align-items:center;justify-content:center;font-size:16px;transition:all .15s;}
   .icon-btn{opacity:.75;}
diff --git a/static/ui.js b/static/ui.js
index c409b8f..fa4121a 100644
--- a/static/ui.js
+++ b/static/ui.js
@@ -84,6 +84,36 @@ let _scrollPinned=true;
 })();
 function _fmtTokens(n){if(!n||n<0)return'0';if(n>=1e6)return(n/1e6).toFixed(1)+'M';if(n>=1e3)return(n/1e3).toFixed(1)+'k';return String(n);}
 
+// Context usage indicator in composer footer
+function _syncCtxIndicator(usage){
+  const el=$('ctxIndicator');
+  if(!el)return;
+  const inTok=usage.input_tokens||0;
+  const outTok=usage.output_tokens||0;
+  const total=inTok+outTok;
+  if(!total){el.style.display='none';return;}
+  el.style.display='';
+  // Estimate context window from model name (rough, covers major families)
+  // TODO: fetch exact values from server or model metadata API
+  const _CTX={claude:200000,gemini:1000000,'gpt-4o':128000,'gpt-5':128000,o3:200000,o4:200000,deepseek:128000,llama:128000};
+  const _m=(S.session&&S.session.model||'').toLowerCase();
+  let ctxWindow=128000;
+  for(const[k,v]of Object.entries(_CTX)){if(_m.includes(k)){ctxWindow=v;break;}}
+  const pct=Math.min(100,Math.round((inTok/ctxWindow)*100));
+  const bar=$('ctxBar');
+  const label=$('ctxLabel');
+  if(bar){
+    bar.style.width=pct+'%';
+    bar.className='ctx-bar'+(pct>75?' ctx-high':pct>50?' ctx-mid':'');
+  }
+  if(label){
+    const cost=usage.estimated_cost;
+    let text=`${_fmtTokens(inTok)} in \u00b7 ${_fmtTokens(outTok)} out`;
+    if(cost) text+=` \u00b7 $${cost<0.01?cost.toFixed(4):cost.toFixed(2)}`;
+    label.textContent=text;
+  }
+}
+
 function scrollIfPinned(){
   if(!_scrollPinned) return;
   const el=$('messages');