diff --git a/packages/data-provider/specs/bedrock.spec.ts b/packages/data-provider/specs/bedrock.spec.ts
index 2a0de6937a..c731d18d5e 100644
--- a/packages/data-provider/specs/bedrock.spec.ts
+++ b/packages/data-provider/specs/bedrock.spec.ts
@@ -14,7 +14,7 @@ describe('bedrockInputParser', () => {
       expect(additionalFields.anthropic_beta).toEqual(['output-128k-2025-02-19']);
     });
 
-    test('should match anthropic.claude-sonnet-4 model', () => {
+    test('should match anthropic.claude-sonnet-4 model with 1M context header', () => {
       const input = {
         model: 'anthropic.claude-sonnet-4',
       };
@@ -22,10 +22,13 @@ describe('bedrockInputParser', () => {
       const additionalFields = result.additionalModelRequestFields as Record<string, unknown>;
       expect(additionalFields.thinking).toBe(true);
       expect(additionalFields.thinkingBudget).toBe(2000);
-      expect(additionalFields.anthropic_beta).toEqual(['output-128k-2025-02-19']);
+      expect(additionalFields.anthropic_beta).toEqual([
+        'output-128k-2025-02-19',
+        'context-1m-2025-08-07',
+      ]);
     });
 
-    test('should match anthropic.claude-opus-5 model', () => {
+    test('should match anthropic.claude-opus-5 model without 1M context header', () => {
       const input = {
         model: 'anthropic.claude-opus-5',
       };
@@ -36,7 +39,7 @@ describe('bedrockInputParser', () => {
       expect(additionalFields.anthropic_beta).toEqual(['output-128k-2025-02-19']);
     });
 
-    test('should match anthropic.claude-haiku-6 model', () => {
+    test('should match anthropic.claude-haiku-6 model without 1M context header', () => {
       const input = {
         model: 'anthropic.claude-haiku-6',
       };
@@ -47,7 +50,7 @@ describe('bedrockInputParser', () => {
       expect(additionalFields.anthropic_beta).toEqual(['output-128k-2025-02-19']);
     });
 
-    test('should match anthropic.claude-4-sonnet model', () => {
+    test('should match anthropic.claude-4-sonnet model with 1M context header', () => {
       const input = {
         model: 'anthropic.claude-4-sonnet',
       };
@@ -55,10 +58,13 @@ describe('bedrockInputParser', () => {
       const additionalFields = result.additionalModelRequestFields as Record<string, unknown>;
       expect(additionalFields.thinking).toBe(true);
       expect(additionalFields.thinkingBudget).toBe(2000);
-      expect(additionalFields.anthropic_beta).toEqual(['output-128k-2025-02-19']);
+      expect(additionalFields.anthropic_beta).toEqual([
+        'output-128k-2025-02-19',
+        'context-1m-2025-08-07',
+      ]);
     });
 
-    test('should match anthropic.claude-4.5-sonnet model', () => {
+    test('should match anthropic.claude-4.5-sonnet model with 1M context header', () => {
       const input = {
         model: 'anthropic.claude-4.5-sonnet',
       };
@@ -66,10 +72,13 @@ describe('bedrockInputParser', () => {
       const additionalFields = result.additionalModelRequestFields as Record<string, unknown>;
       expect(additionalFields.thinking).toBe(true);
       expect(additionalFields.thinkingBudget).toBe(2000);
-      expect(additionalFields.anthropic_beta).toEqual(['output-128k-2025-02-19']);
+      expect(additionalFields.anthropic_beta).toEqual([
+        'output-128k-2025-02-19',
+        'context-1m-2025-08-07',
+      ]);
     });
 
-    test('should match anthropic.claude-4-7-sonnet model', () => {
+    test('should match anthropic.claude-4-7-sonnet model with 1M context header', () => {
       const input = {
         model: 'anthropic.claude-4-7-sonnet',
       };
@@ -77,7 +86,24 @@ describe('bedrockInputParser', () => {
       const additionalFields = result.additionalModelRequestFields as Record<string, unknown>;
       expect(additionalFields.thinking).toBe(true);
       expect(additionalFields.thinkingBudget).toBe(2000);
-      expect(additionalFields.anthropic_beta).toEqual(['output-128k-2025-02-19']);
+      expect(additionalFields.anthropic_beta).toEqual([
+        'output-128k-2025-02-19',
+        'context-1m-2025-08-07',
+      ]);
+    });
+
+    test('should match anthropic.claude-sonnet-4-20250514-v1:0 with full model ID', () => {
+      const input = {
+        model: 'anthropic.claude-sonnet-4-20250514-v1:0',
+      };
+      const result = bedrockInputParser.parse(input) as BedrockConverseInput;
+      const additionalFields = result.additionalModelRequestFields as Record<string, unknown>;
+      expect(additionalFields.thinking).toBe(true);
+      expect(additionalFields.thinkingBudget).toBe(2000);
+      expect(additionalFields.anthropic_beta).toEqual([
+        'output-128k-2025-02-19',
+        'context-1m-2025-08-07',
+      ]);
     });
 
     test('should not match non-Claude models', () => {
@@ -110,7 +136,7 @@ describe('bedrockInputParser', () => {
       expect(additionalFields?.anthropic_beta).toBeUndefined();
     });
 
-    test('should respect explicit thinking configuration', () => {
+    test('should respect explicit thinking configuration but still add beta headers', () => {
       const input = {
         model: 'anthropic.claude-sonnet-4',
         thinking: false,
@@ -119,6 +145,10 @@ describe('bedrockInputParser', () => {
       const additionalFields = result.additionalModelRequestFields as Record<string, unknown>;
       expect(additionalFields.thinking).toBeUndefined();
       expect(additionalFields.thinkingBudget).toBeUndefined();
+      expect(additionalFields.anthropic_beta).toEqual([
+        'output-128k-2025-02-19',
+        'context-1m-2025-08-07',
+      ]);
     });
 
     test('should respect custom thinking budget', () => {
diff --git a/packages/data-provider/src/bedrock.ts b/packages/data-provider/src/bedrock.ts
index b37fdc25e1..4df6bd6b65 100644
--- a/packages/data-provider/src/bedrock.ts
+++ b/packages/data-provider/src/bedrock.ts
@@ -15,6 +15,36 @@ type AnthropicInput = BedrockConverseInput & {
     AnthropicReasoning;
 };
 
+/**
+ * Gets the appropriate anthropic_beta headers for Bedrock Anthropic models.
+ * Bedrock uses `anthropic_beta` (with underscore) in additionalModelRequestFields.
+ *
+ * @param model - The Bedrock model identifier (e.g., "anthropic.claude-sonnet-4-20250514-v1:0")
+ * @returns Array of beta header strings, or empty array if not applicable
+ */
+function getBedrockAnthropicBetaHeaders(model: string): string[] {
+  const betaHeaders: string[] = [];
+
+  const isClaudeThinkingModel =
+    model.includes('anthropic.claude-3-7-sonnet') ||
+    /anthropic\.claude-(?:[4-9](?:\.\d+)?(?:-\d+)?-(?:sonnet|opus|haiku)|(?:sonnet|opus|haiku)-[4-9])/.test(
+      model,
+    );
+
+  const isSonnet4PlusModel =
+    /anthropic\.claude-(?:sonnet-[4-9]|[4-9](?:\.\d+)?(?:-\d+)?-sonnet)/.test(model);
+
+  if (isClaudeThinkingModel) {
+    betaHeaders.push('output-128k-2025-02-19');
+  }
+
+  if (isSonnet4PlusModel) {
+    betaHeaders.push('context-1m-2025-08-07');
+  }
+
+  return betaHeaders;
+}
+
 export const bedrockInputSchema = s.tConversationSchema
   .pick({
     /* LibreChat params; optionType: 'conversation' */
@@ -138,7 +168,10 @@ export const bedrockInputParser = s.tConversationSchema
         additionalFields.thinkingBudget = 2000;
       }
       if (typedData.model.includes('anthropic.')) {
-        additionalFields.anthropic_beta = ['output-128k-2025-02-19'];
+        const betaHeaders = getBedrockAnthropicBetaHeaders(typedData.model);
+        if (betaHeaders.length > 0) {
+          additionalFields.anthropic_beta = betaHeaders;
+        }
       }
     } else if (additionalFields.thinking != null || additionalFields.thinkingBudget != null) {
       delete additionalFields.thinking;