Native tool calling

package.json

@@ -62,5 +62,8 @@
 			"form-data": ">=4.0.4",
 			"bluebird": ">=3.7.2"
 		}
+	},
+	"dependencies": {
+		"@streamparser/json": "^0.0.22"
 	}
 }

packages/types/src/global-settings.ts

@@ -159,6 +159,7 @@ export const globalSettingsSchema = z.object({
 	rateLimitSeconds: z.number().optional(),
 	diffEnabled: z.boolean().optional(),
 	fuzzyMatchThreshold: z.number().optional(),
+
 	experiments: experimentsSchema.optional(),
 
 	codebaseIndexModels: codebaseIndexModelsSchema.optional(),

src/api/index.ts

@@ -3,6 +3,7 @@ import { Anthropic } from "@anthropic-ai/sdk"
 import type { ProviderSettings, ModelInfo } from "@roo-code/types"
 
 import { ApiStream } from "./transform/stream"
+import type { ToolSpec } from "./transform/tool-converters"
 
 import {
 	GlamaHandler,
@@ -73,6 +74,7 @@ export interface ApiHandler {
 		systemPrompt: string,
 		messages: Anthropic.Messages.MessageParam[],
 		metadata?: ApiHandlerCreateMessageMetadata,
+		tools?: ToolSpec[],
 	): ApiStream
 
 	getModel(): { id: string; info: ModelInfo }
@@ -86,6 +88,15 @@ export interface ApiHandler {
 	 * @returns A promise resolving to the token count
 	 */
 	countTokens(content: Array<Anthropic.Messages.ContentBlockParam>): Promise<number>
+
+	/**
+	 * Returns whether this provider supports native tool calling
+	 * Providers that support native tools can receive tool specifications and
+	 * handle them in their native format instead of using XML-based tools
+	 *
+	 * @returns true if the provider supports native tool calling, false otherwise
+	 */
+	supportsNativeTools(): boolean
 }
 
 export function buildApiHandler(configuration: ProviderSettings): ApiHandler {

src/api/providers/anthropic.ts

@@ -14,6 +14,7 @@ import type { ApiHandlerOptions } from "../../shared/api"
 
 import { ApiStream } from "../transform/stream"
 import { getModelParams } from "../transform/model-params"
+import { toolSpecToAnthropicTool, type ToolSpec } from "../transform/tool-converters"
 
 import { BaseProvider } from "./base-provider"
 import type { SingleCompletionHandler, ApiHandlerCreateMessageMetadata } from "../index"
@@ -40,6 +41,7 @@ export class AnthropicHandler extends BaseProvider implements SingleCompletionHa
 		systemPrompt: string,
 		messages: Anthropic.Messages.MessageParam[],
 		metadata?: ApiHandlerCreateMessageMetadata,
+		tools?: ToolSpec[],
 	): ApiStream {
 		let stream: AnthropicStream<Anthropic.Messages.RawMessageStreamEvent>
 		const cacheControl: CacheControlEphemeral = { type: "ephemeral" }
@@ -53,6 +55,10 @@ export class AnthropicHandler extends BaseProvider implements SingleCompletionHa
 			betas.push("context-1m-2025-08-07")
 		}
 
+		// Convert tools to Anthropic format if provided
+		const anthropicTools = tools?.map(toolSpecToAnthropicTool)
+		const nativeToolsOn = anthropicTools && anthropicTools.length > 0
+
 		switch (modelId) {
 			case "claude-sonnet-4-5":
 			case "claude-sonnet-4-20250514":
@@ -107,6 +113,7 @@ export class AnthropicHandler extends BaseProvider implements SingleCompletionHa
 							return message
 						}),
 						stream: true,
+						tools: nativeToolsOn ? anthropicTools : undefined,
 					},
 					(() => {
 						// prompt caching: https://x.com/alexalbert__/status/1823751995901272068
@@ -151,6 +158,7 @@ export class AnthropicHandler extends BaseProvider implements SingleCompletionHa
 		let outputTokens = 0
 		let cacheWriteTokens = 0
 		let cacheReadTokens = 0
+		const lastStartedToolCall = { id: "", name: "", arguments: "" }
 
 		for await (const chunk of stream) {
 			switch (chunk.type) {
@@ -202,6 +210,14 @@ export class AnthropicHandler extends BaseProvider implements SingleCompletionHa
 
 							yield { type: "reasoning", text: chunk.content_block.thinking }
 							break
+						case "tool_use":
+							// Convert Anthropic tool_use to OpenAI-compatible format
+							if (chunk.content_block.id && chunk.content_block.name) {
+								lastStartedToolCall.id = chunk.content_block.id
+								lastStartedToolCall.name = chunk.content_block.name
+								lastStartedToolCall.arguments = ""
+							}
+							break
 						case "text":
 							// We may receive multiple text blocks, in which
 							// case just insert a line break between them.
@@ -218,13 +234,32 @@ export class AnthropicHandler extends BaseProvider implements SingleCompletionHa
 						case "thinking_delta":
 							yield { type: "reasoning", text: chunk.delta.thinking }
 							break
+						case "input_json_delta":
+							// Stream tool arguments as they arrive
+							if (lastStartedToolCall.id && lastStartedToolCall.name && chunk.delta.partial_json) {
+								yield {
+									type: "tool_calls",
+									tool_call: {
+										function: {
+											id: lastStartedToolCall.id,
+											name: lastStartedToolCall.name,
+											arguments: chunk.delta.partial_json,
+										},
+									},
+								}
+							}
+							break
 						case "text_delta":
 							yield { type: "text", text: chunk.delta.text }
 							break
 					}
 
 					break
 				case "content_block_stop":
+					// Reset tool call state when block ends
+					lastStartedToolCall.id = ""
+					lastStartedToolCall.name = ""
+					lastStartedToolCall.arguments = ""
 					break
 			}
 		}
@@ -326,4 +361,8 @@ export class AnthropicHandler extends BaseProvider implements SingleCompletionHa
 			return super.countTokens(content)
 		}
 	}
+
+	protected override hasNativeToolCapability(): boolean {
+		return true
+	}
 }

src/api/providers/base-provider.ts

@@ -1,4 +1,5 @@
 import { Anthropic } from "@anthropic-ai/sdk"
+import * as vscode from "vscode"
 
 import type { ModelInfo } from "@roo-code/types"
 
@@ -32,4 +33,28 @@ export abstract class BaseProvider implements ApiHandler {
 
 		return countTokens(content, { useWorker: true })
 	}
+
+	/**
+	 * Returns whether this provider has the capability to support native tool calling.
+	 * Default implementation returns false (no native tool support).
+	 * Providers that DO support native tools should override this to return true.
+	 *
+	 * @returns false by default
+	 */
+	protected hasNativeToolCapability(): boolean {
+		return false
+	}
+
+	/**
+	 * Returns whether this provider supports native tool calling AND the user has enabled it.
+	 * Combines provider capability with user setting.
+	 *
+	 * @returns true if provider supports it AND setting is enabled, false otherwise
+	 */
+	supportsNativeTools(): boolean {
+		if (!this.hasNativeToolCapability()) {
+			return false
+		}
+		return vscode.workspace.getConfiguration("roo-cline").get<boolean>("nativeToolCalling", false)
+	}
 }

src/api/providers/fake-ai.ts

@@ -78,4 +78,8 @@ export class FakeAIHandler implements ApiHandler, SingleCompletionHandler {
 	completePrompt(prompt: string): Promise<string> {
 		return this.ai.completePrompt(prompt)
 	}
+
+	supportsNativeTools(): boolean {
+		return false
+	}
 }

src/api/providers/human-relay.ts

@@ -94,6 +94,10 @@ export class HumanRelayHandler implements ApiHandler, SingleCompletionHandler {
 
 		return response
 	}
+
+	supportsNativeTools(): boolean {
+		return false
+	}
 }
 
 /**