diff --git a/source/utils/auto-compact.spec.ts b/source/utils/auto-compact.spec.ts
index b205eb18..807a09df 100644
--- a/source/utils/auto-compact.spec.ts
+++ b/source/utils/auto-compact.spec.ts
@@ -15,6 +15,7 @@ import {
 	setAutoCompactStrategy,
 	setAutoCompactThreshold,
 } from './auto-compact';
+import {COMPRESSION_CONSTANTS} from './message-compression';
 
 // Reset session overrides before each test
 test.beforeEach(() => {
@@ -51,24 +52,36 @@ test('setAutoCompactThreshold sets threshold value', t => {
 	t.is(autoCompactSessionOverrides.threshold, 75);
 });
 
-test('setAutoCompactThreshold clamps to minimum of 50', t => {
-	setAutoCompactThreshold(30);
-	t.is(autoCompactSessionOverrides.threshold, 50);
+test('setAutoCompactThreshold clamps to the configured minimum', t => {
+	setAutoCompactThreshold(COMPRESSION_CONSTANTS.MIN_THRESHOLD_PERCENT - 20);
+	t.is(
+		autoCompactSessionOverrides.threshold,
+		COMPRESSION_CONSTANTS.MIN_THRESHOLD_PERCENT,
+	);
 });
 
-test('setAutoCompactThreshold clamps to maximum of 95', t => {
-	setAutoCompactThreshold(99);
-	t.is(autoCompactSessionOverrides.threshold, 95);
+test('setAutoCompactThreshold clamps to the configured maximum', t => {
+	setAutoCompactThreshold(COMPRESSION_CONSTANTS.MAX_THRESHOLD_PERCENT + 4);
+	t.is(
+		autoCompactSessionOverrides.threshold,
+		COMPRESSION_CONSTANTS.MAX_THRESHOLD_PERCENT,
+	);
 });
 
-test('setAutoCompactThreshold handles boundary value 50', t => {
-	setAutoCompactThreshold(50);
-	t.is(autoCompactSessionOverrides.threshold, 50);
+test('setAutoCompactThreshold handles the configured minimum', t => {
+	setAutoCompactThreshold(COMPRESSION_CONSTANTS.MIN_THRESHOLD_PERCENT);
+	t.is(
+		autoCompactSessionOverrides.threshold,
+		COMPRESSION_CONSTANTS.MIN_THRESHOLD_PERCENT,
+	);
 });
 
-test('setAutoCompactThreshold handles boundary value 95', t => {
-	setAutoCompactThreshold(95);
-	t.is(autoCompactSessionOverrides.threshold, 95);
+test('setAutoCompactThreshold handles the configured maximum', t => {
+	setAutoCompactThreshold(COMPRESSION_CONSTANTS.MAX_THRESHOLD_PERCENT);
+	t.is(
+		autoCompactSessionOverrides.threshold,
+		COMPRESSION_CONSTANTS.MAX_THRESHOLD_PERCENT,
+	);
 });
 
 test('setAutoCompactThreshold sets threshold to null', t => {
diff --git a/source/utils/auto-compact.ts b/source/utils/auto-compact.ts
index ef3fccd2..d3455464 100644
--- a/source/utils/auto-compact.ts
+++ b/source/utils/auto-compact.ts
@@ -8,7 +8,7 @@ import {calculateToolDefinitionsTokensFromDefs} from '@/usage/calculator';
 import {getLogger} from '@/utils/logging';
 import {compressionBackup} from './compression-backup';
 import {summariseWithLLM} from './llm-summariser';
-import {compressMessages} from './message-compression';
+import {COMPRESSION_CONSTANTS, compressMessages} from './message-compression';
 import {filterModelFacing} from './message-visibility';
 import {createSessionOverride} from './session-override';
 
@@ -19,11 +19,16 @@ export interface AutoCompactSessionOverrides {
 	strategy: CompressionStrategy | null;
 }
 
-// Session overrides for auto-compact. `threshold` is clamped to 50–95.
+// Session overrides for auto-compact. `threshold` is clamped to the configured range.
 const autoCompactSession = {
 	enabled: createSessionOverride<boolean>(),
 	threshold: createSessionOverride<number>(value =>
-		value !== null ? Math.max(50, Math.min(95, value)) : null,
+		value !== null
+			? Math.max(
+					COMPRESSION_CONSTANTS.MIN_THRESHOLD_PERCENT,
+					Math.min(COMPRESSION_CONSTANTS.MAX_THRESHOLD_PERCENT, value),
+				)
+			: null,
 	),
 	mode: createSessionOverride<CompressionMode>(),
 	strategy: createSessionOverride<CompressionStrategy>(),