diff --git a/apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.test.ts b/apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.test.ts
index 40f33b3a1a309..265ca24c4236c 100644
--- a/apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.test.ts
+++ b/apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.test.ts
@@ -6077,7 +6077,7 @@ describe("ClaudeAdapterV2 background wake turns", () => {
             ? [event.providerTurn.tokenUsage.autoCompactThreshold]
             : [],
         ),
-        [150_000, 150_000, 150_000, 150_000],
+        [117_000, 117_000, 117_000, 117_000],
       );
     }).pipe(
       Effect.provide(
@@ -6088,10 +6088,10 @@ describe("ClaudeAdapterV2 background wake turns", () => {
 
   it.effect.each([
     { autoCompactWindow: "", model: "claude-sonnet-4-6", threshold: undefined },
-    { autoCompactWindow: "150000", model: "claude-sonnet-4-6", threshold: 150_000 },
+    { autoCompactWindow: "150000", model: "claude-sonnet-4-6", threshold: 117_000 },
     { autoCompactWindow: "200000", model: "claude-sonnet-4-6", threshold: undefined },
     { autoCompactWindow: "650000", model: "claude-sonnet-4-6", threshold: undefined },
-    { autoCompactWindow: "650000", model: "uncatalogued-model", threshold: 650_000 },
+    { autoCompactWindow: "650000", model: "uncatalogued-model", threshold: 617_000 },
   ])(
     "ignores stale snapshots after compaction and reports threshold $autoCompactWindow for $model",
     ({ autoCompactWindow, model, threshold }) =>
diff --git a/apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.ts b/apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.ts
index f42f37d1ab1b1..aeb4e5f58234d 100644
--- a/apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.ts
+++ b/apps/server/src/orchestration-v2/Adapters/ClaudeAdapterV2.ts
@@ -231,10 +231,14 @@ function claudePromptCacheTtlMs(
 }
 
 // Claude caps the window at the model's context, so a setting at or above it never applies.
+// Below that, Claude compacts 33,000 tokens short of the window: Claude Code 2.1.305's
+// getContextUsage reports a 150,000 window as a 117,000 threshold, for every catalog model.
+const CLAUDE_AUTO_COMPACT_RESERVE_TOKENS = 33_000;
+
 function claudeAutoCompactThreshold(autoCompactWindow: string, maxTokens: number | null) {
-  const threshold = Number(autoCompactWindow);
-  return threshold > 0 && (maxTokens === null || threshold < maxTokens)
-    ? { autoCompactThreshold: threshold }
+  const windowTokens = Number(autoCompactWindow);
+  return windowTokens > 0 && (maxTokens === null || windowTokens < maxTokens)
+    ? { autoCompactThreshold: windowTokens - CLAUDE_AUTO_COMPACT_RESERVE_TOKENS }
     : {};
 }