diff --git a/src/app/(dashboard)/dashboard/cli-tools/components/ClaudeToolCard.js b/src/app/(dashboard)/dashboard/cli-tools/components/ClaudeToolCard.js
index fad05f9e..f49d8a38 100644
--- a/src/app/(dashboard)/dashboard/cli-tools/components/ClaudeToolCard.js
+++ b/src/app/(dashboard)/dashboard/cli-tools/components/ClaudeToolCard.js
@@ -7,19 +7,25 @@ import BaseUrlSelect from "./BaseUrlSelect";
 import { rememberEndpoint } from "./cliEndpointPresets";
 import ApiKeySelect from "./ApiKeySelect";
 import { matchKnownEndpoint } from "./cliEndpointMatch";
+import { stripModelContextMarker } from "open-sse/utils/modelMarkers.js";
 
 const CLOUD_URL = process.env.NEXT_PUBLIC_CLOUD_URL;
 
-// Context window presets. UI shows the round number; the value written is nudged
-// down 2K to stay safely under the upstream hard cap.
+// Auto-compact window presets (CLAUDE_CODE_AUTO_COMPACT_WINDOW, valid 100K–1M).
+// UI shows the round number; the value written is nudged down 2K to stay safely
+// under the upstream hard cap.
 const CONTEXT_OPTIONS = [
   { label: "Default", value: "" },
   { label: "200K", value: "198000" },
   { label: "300K", value: "298000" },
   { label: "500K", value: "498000" },
-  { label: "1M", value: "998000" },
+  { label: "700K", value: "698000" },
 ];
 
+// Claude Code assumes a model's window is 200K unless the name carries the `[1m]`
+// marker, which is why the 1M auto-compact preset only takes effect once the
+// marker is applied.
+
 export default function ClaudeToolCard({
   tool,
   isExpanded,
@@ -51,9 +57,28 @@ export default function ClaudeToolCard({
   const [customBaseUrl, setCustomBaseUrl] = useState("");
   const [ccFilterNaming, setCcFilterNaming] = useState(false);
   const [exaMcpEnabled, setExaMcpEnabled] = useState(false);
-  const [maxContextTokens, setMaxContextTokens] = useState("");
+  const [autoCompactWindow, setAutoCompactWindow] = useState("");
+  const [oneMContext, setOneMContext] = useState(false);
   const hasInitializedModels = useRef(false);
 
+  // Claude Code only string-matches the marker against the model name, so it
+  // applies to any id — the user decides which models are worth declaring as 1M.
+  // Stripping first keeps repeated toggles from stacking `[1m][1m]`.
+  const withContextMarker = (value, enabled) => {
+    const { model } = stripModelContextMarker(value);
+    return enabled ? `${model}[1m]` : model;
+  };
+
+  // Rewrite the mappings in place on toggle, so the inputs show what will be
+  // written without waiting for Apply.
+  const handleOneMContextToggle = (enabled) => {
+    setOneMContext(enabled);
+    tool.defaultModels.forEach((model) => {
+      const current = modelMappings[model.alias];
+      if (current) onModelMappingChange(model.alias, withContextMarker(current, enabled));
+    });
+  };
+
   const currentBaseUrl = claudeStatus?.settings?.env?.ANTHROPIC_BASE_URL || "";
 
   const getConfigStatus = () => {
@@ -80,9 +105,15 @@ export default function ClaudeToolCard({
   }, [initialStatus]);
 
   useEffect(() => {
-    const v = claudeStatus?.settings?.env?.CLAUDE_CODE_MAX_CONTEXT_TOKENS;
-    setMaxContextTokens(v || "");
-  }, [claudeStatus?.settings?.env?.CLAUDE_CODE_MAX_CONTEXT_TOKENS]);
+    const v = claudeStatus?.settings?.env?.CLAUDE_CODE_AUTO_COMPACT_WINDOW;
+    setAutoCompactWindow(v || "");
+  }, [claudeStatus?.settings?.env?.CLAUDE_CODE_AUTO_COMPACT_WINDOW]);
+
+  useEffect(() => {
+    const env = claudeStatus?.settings?.env;
+    if (!env) return;
+    setOneMContext(tool.defaultModels.some((model) => env[model.envKey]?.endsWith("[1m]")));
+  }, [claudeStatus?.settings?.env, tool.defaultModels]);
 
   useEffect(() => {
     if (isExpanded) {
@@ -124,6 +155,8 @@ export default function ClaudeToolCard({
 
       tool.defaultModels.forEach((model) => {
         if (model.envKey) {
+          // Kept verbatim (marker included) so the input matches what is on disk;
+          // withContextMarker strips before appending, so re-applying cannot double it.
           const value = env[model.envKey] || model.defaultValue || "";
           // Only sync initial values from file once
           if (value) {
@@ -180,15 +213,17 @@ export default function ClaudeToolCard({
 
       tool.defaultModels.forEach((model) => {
         const targetModel = modelMappings[model.alias];
+        // Written verbatim — the input may hold a marker typed by hand, and the
+        // toggle already decided the marker when it was flipped.
         if (targetModel && model.envKey) env[model.envKey] = targetModel;
       });
-      if (maxContextTokens) {
-        env.CLAUDE_CODE_MAX_CONTEXT_TOKENS = maxContextTokens;
+      if (autoCompactWindow) {
+        env.CLAUDE_CODE_AUTO_COMPACT_WINDOW = autoCompactWindow;
       }
       const res = await fetch("/api/cli-tools/claude-settings", {
         method: "POST",
         headers: { "Content-Type": "application/json" },
-        body: JSON.stringify({ env, exaMcpEnabled, maxContextTokens }),
+        body: JSON.stringify({ env, exaMcpEnabled, autoCompactWindow }),
       });
       const data = await res.json();
       if (res.ok) {
@@ -217,7 +252,8 @@ export default function ClaudeToolCard({
         tool.defaultModels.forEach((model) => onModelMappingChange(model.alias, model.defaultValue || ""));
         setSelectedApiKey("");
         setExaMcpEnabled(false);
-        setMaxContextTokens("");
+        setAutoCompactWindow("");
+        setOneMContext(false);
       } else {
         setMessage({ type: "error", text: data.error || "Failed to reset settings" });
       }
@@ -247,8 +283,8 @@ export default function ClaudeToolCard({
       const targetModel = modelMappings[model.alias];
       if (targetModel && model.envKey) env[model.envKey] = targetModel;
     });
-    if (maxContextTokens) {
-      env.CLAUDE_CODE_MAX_CONTEXT_TOKENS = maxContextTokens;
+    if (autoCompactWindow) {
+      env.CLAUDE_CODE_AUTO_COMPACT_WINDOW = autoCompactWindow;
     }
 
     return [
@@ -374,17 +410,30 @@ export default function ClaudeToolCard({
                   </div>
                 ))}
 
-                {/* Context Window */}
+                {/* Auto-compact window */}
                 <div className="grid grid-cols-1 gap-1.5 sm:grid-cols-[8rem_auto_1fr_auto] sm:items-center sm:gap-2">
-                  <span className="text-xs font-semibold text-text-main sm:text-right sm:text-sm">Context window</span>
+                  <span className="text-xs font-semibold text-text-main sm:text-right sm:text-sm">Auto-compact</span>
                   <span className="material-symbols-outlined hidden text-text-muted text-[14px] sm:inline">arrow_forward</span>
-                  <select value={maxContextTokens} onChange={(e) => setMaxContextTokens(e.target.value)} className="w-full min-w-0 px-2 py-2 bg-surface rounded border border-border text-xs focus:outline-none focus:ring-1 focus:ring-primary/50 sm:py-1.5">
+                  <select value={autoCompactWindow} onChange={(e) => setAutoCompactWindow(e.target.value)} className="w-full min-w-0 px-2 py-2 bg-surface rounded border border-border text-xs focus:outline-none focus:ring-1 focus:ring-primary/50 sm:py-1.5">
                     {CONTEXT_OPTIONS.map((opt) => (
                       <option key={opt.label} value={opt.value}>{opt.label}</option>
                     ))}
                   </select>
                 </div>
 
+                {/* 1M context */}
+                <div className="grid grid-cols-1 gap-1.5 sm:grid-cols-[8rem_auto_1fr_auto] sm:items-center sm:gap-2">
+                  <span className="text-xs font-semibold text-text-main sm:text-right sm:text-sm">1M context</span>
+                  <span className="material-symbols-outlined hidden text-text-muted text-[14px] sm:inline">arrow_forward</span>
+                  <label className="flex items-center gap-1.5 cursor-pointer select-none">
+                    <input type="checkbox" checked={oneMContext} onChange={(e) => handleOneMContextToggle(e.target.checked)} className="w-3.5 h-3.5 accent-primary cursor-pointer" />
+                    <span className="text-xs text-text-muted">Append [1m] to the model name</span>
+                    <Tooltip text="Claude Code otherwise assumes a 200K window, which clamps the auto-compact window above. Applied to every mapped model — only enable it for models that really accept 1M.">
+                      <span className="material-symbols-outlined text-text-muted text-[14px] cursor-help">info</span>
+                    </Tooltip>
+                  </label>
+                </div>
+
                 {/* CC Filter Naming */}
                 <div className="grid grid-cols-1 gap-1.5 sm:grid-cols-[8rem_auto_1fr_auto] sm:items-center sm:gap-2">
                   <span className="text-xs font-semibold text-text-main sm:text-right sm:text-sm">Filter naming</span>
diff --git a/src/app/api/cli-tools/claude-settings/route.js b/src/app/api/cli-tools/claude-settings/route.js
index 76ba9232..c7087577 100644
--- a/src/app/api/cli-tools/claude-settings/route.js
+++ b/src/app/api/cli-tools/claude-settings/route.js
@@ -123,7 +123,7 @@ export async function GET() {
 // POST - Backup old fields and write new settings
 export async function POST(request) {
   try {
-    const { env, exaMcpEnabled, maxContextTokens } = await request.json();
+    const { env, exaMcpEnabled, autoCompactWindow } = await request.json();
     
     if (!env || typeof env !== "object") {
       return NextResponse.json(
@@ -166,12 +166,13 @@ export async function POST(request) {
       },
     };
 
-    // CLAUDE_CODE_MAX_CONTEXT_TOKENS — only set when a concrete value is chosen;
-    // "Default" removes the key so Claude Code falls back to the model's window.
-    if (maxContextTokens) {
-      newSettings.env.CLAUDE_CODE_MAX_CONTEXT_TOKENS = String(maxContextTokens);
+    // CLAUDE_CODE_AUTO_COMPACT_WINDOW — the token threshold that triggers
+    // auto-compact. Only set when a concrete value is chosen; "Default" removes
+    // the key so Claude Code derives the window from the model.
+    if (autoCompactWindow) {
+      newSettings.env.CLAUDE_CODE_AUTO_COMPACT_WINDOW = String(autoCompactWindow);
     } else {
-      delete newSettings.env.CLAUDE_CODE_MAX_CONTEXT_TOKENS;
+      delete newSettings.env.CLAUDE_CODE_AUTO_COMPACT_WINDOW;
     }
 
     // Write new settings
@@ -203,7 +204,7 @@ const RESET_ENV_KEYS = [
   "ANTHROPIC_DEFAULT_SONNET_MODEL",
   "ANTHROPIC_DEFAULT_HAIKU_MODEL",
   "API_TIMEOUT_MS",
-  "CLAUDE_CODE_MAX_CONTEXT_TOKENS",
+  "CLAUDE_CODE_AUTO_COMPACT_WINDOW",
 ];
 
 // DELETE - Reset settings (remove env fields)