diff --git a/src/api/providers/__tests__/bedrock.spec.ts b/src/api/providers/__tests__/bedrock.spec.ts
index 40daa2fffa..8df495ca9f 100644
--- a/src/api/providers/__tests__/bedrock.spec.ts
+++ b/src/api/providers/__tests__/bedrock.spec.ts
@@ -635,9 +635,11 @@ describe("AwsBedrockHandler", () => {
 			expect(mockConverseStreamCommand).toHaveBeenCalled()
 			const commandArg = mockConverseStreamCommand.mock.calls[0][0] as any
 
-			// Should include anthropic_beta parameter but NOT anthropic_version (only for thinking)
-			expect(commandArg.anthropic_beta).toEqual(["context-1m-2025-08-07"])
-			expect(commandArg.anthropic_version).toBeUndefined()
+			// Should include anthropic_beta in additionalModelRequestFields
+			expect(commandArg.additionalModelRequestFields).toBeDefined()
+			expect(commandArg.additionalModelRequestFields.anthropic_beta).toEqual(["context-1m-2025-08-07"])
+			// Should not include anthropic_version since thinking is not enabled
+			expect(commandArg.additionalModelRequestFields.anthropic_version).toBeUndefined()
 		})
 
 		it("should not include anthropic_beta parameter when 1M context is disabled", async () => {
@@ -663,8 +665,8 @@ describe("AwsBedrockHandler", () => {
 			expect(mockConverseStreamCommand).toHaveBeenCalled()
 			const commandArg = mockConverseStreamCommand.mock.calls[0][0] as any
 
-			// Should not include anthropic_beta parameter
-			expect(commandArg.anthropic_beta).toBeUndefined()
+			// Should not include anthropic_beta in additionalModelRequestFields
+			expect(commandArg.additionalModelRequestFields).toBeUndefined()
 		})
 
 		it("should not include anthropic_beta parameter for non-Claude Sonnet 4 models", async () => {
@@ -690,8 +692,8 @@ describe("AwsBedrockHandler", () => {
 			expect(mockConverseStreamCommand).toHaveBeenCalled()
 			const commandArg = mockConverseStreamCommand.mock.calls[0][0] as any
 
-			// Should not include anthropic_beta parameter for non-Sonnet 4 models
-			expect(commandArg.anthropic_beta).toBeUndefined()
+			// Should not include anthropic_beta for non-Sonnet 4 models
+			expect(commandArg.additionalModelRequestFields).toBeUndefined()
 		})
 
 		it("should enable 1M context window with cross-region inference for Claude Sonnet 4", () => {
@@ -738,9 +740,11 @@ describe("AwsBedrockHandler", () => {
 				mockConverseStreamCommand.mock.calls.length - 1
 			][0] as any
 
-			// Should include anthropic_beta parameter but NOT anthropic_version (only for thinking)
-			expect(commandArg.anthropic_beta).toEqual(["context-1m-2025-08-07"])
-			expect(commandArg.anthropic_version).toBeUndefined()
+			// Should include anthropic_beta in additionalModelRequestFields
+			expect(commandArg.additionalModelRequestFields).toBeDefined()
+			expect(commandArg.additionalModelRequestFields.anthropic_beta).toEqual(["context-1m-2025-08-07"])
+			// Should not include anthropic_version since thinking is not enabled
+			expect(commandArg.additionalModelRequestFields.anthropic_version).toBeUndefined()
 			// Model ID should have cross-region prefix
 			expect(commandArg.modelId).toBe(`us.${BEDROCK_CLAUDE_SONNET_4_MODEL_ID}`)
 		})
diff --git a/src/api/providers/bedrock.ts b/src/api/providers/bedrock.ts
index 5471f2a01f..c6a0b35df4 100644
--- a/src/api/providers/bedrock.ts
+++ b/src/api/providers/bedrock.ts
@@ -47,12 +47,14 @@ interface BedrockInferenceConfig {
 	topP?: number
 }
 
-// Define interface for Bedrock thinking configuration
-interface BedrockThinkingConfig {
-	thinking: {
+// Define interface for Bedrock additional model request fields
+// This includes thinking configuration, 1M context beta, and other model-specific parameters
+interface BedrockAdditionalModelFields {
+	thinking?: {
 		type: "enabled"
 		budget_tokens: number
 	}
+	anthropic_beta?: string[]
 	[key: string]: any // Add index signature to be compatible with DocumentType
 }
 
@@ -63,8 +65,7 @@ interface BedrockPayload {
 	system?: SystemContentBlock[]
 	inferenceConfig: BedrockInferenceConfig
 	anthropic_version?: string
-	anthropic_beta?: string[]
-	additionalModelRequestFields?: BedrockThinkingConfig
+	additionalModelRequestFields?: BedrockAdditionalModelFields
 }
 
 // Define specific types for content block events to avoid 'as any' usage
@@ -341,7 +342,7 @@ export class AwsBedrockHandler extends BaseProvider implements SingleCompletionH
 			conversationId,
 		)
 
-		let additionalModelRequestFields: BedrockThinkingConfig | undefined
+		let additionalModelRequestFields: BedrockAdditionalModelFields | undefined
 		let thinkingEnabled = false
 
 		// Determine if thinking should be enabled
@@ -382,16 +383,22 @@ export class AwsBedrockHandler extends BaseProvider implements SingleCompletionH
 		const baseModelId = this.parseBaseModelId(modelConfig.id)
 		const is1MContextEnabled = baseModelId === BEDROCK_CLAUDE_SONNET_4_MODEL_ID && this.options.awsBedrock1MContext
 
+		// Add anthropic_beta for 1M context to additionalModelRequestFields
+		if (is1MContextEnabled) {
+			if (!additionalModelRequestFields) {
+				additionalModelRequestFields = {} as BedrockAdditionalModelFields
+			}
+			additionalModelRequestFields.anthropic_beta = ["context-1m-2025-08-07"]
+		}
+
 		const payload: BedrockPayload = {
 			modelId: modelConfig.id,
 			messages: formatted.messages,
 			system: formatted.system,
 			inferenceConfig,
 			...(additionalModelRequestFields && { additionalModelRequestFields }),
-			// Add anthropic_version when using thinking features
+			// Add anthropic_version at top level when using thinking features
 			...(thinkingEnabled && { anthropic_version: "bedrock-2023-05-31" }),
-			// Add anthropic_beta when 1M context is enabled
-			...(is1MContextEnabled && { anthropic_beta: ["context-1m-2025-08-07"] }),
 		}
 
 		// Create AbortController with 10 minute timeout