diff --git a/apps/cli/src/runtime/run-interactive.ts b/apps/cli/src/runtime/run-interactive.ts
index 037e09179a..cc6e0143b1 100644
--- a/apps/cli/src/runtime/run-interactive.ts
+++ b/apps/cli/src/runtime/run-interactive.ts
@@ -1,4 +1,5 @@
 import {
+	createComputerUseToolFromEnv,
 	getCurrentContextSize,
 	type ProviderSettings,
 	ProviderSettingsManager,
@@ -258,7 +259,15 @@ export async function runInteractive(
 		tuiModeChanged,
 	});
 
-	config.extraTools = config.mode === "plan" ? [switchToActModeTool] : [];
+	// Proof-of-concept computer-use support: only enabled when
+	// CLINE_COMPUTER_USE_PORT points at a running backend. See
+	// @cline/core's extensions/computer-use/README.md for the wire protocol.
+	const computerUseTool = await createComputerUseToolFromEnv();
+
+	config.extraTools = [
+		...(config.mode === "plan" ? [switchToActModeTool] : []),
+		...(computerUseTool ? [computerUseTool] : []),
+	];
 
 	const uiEvents = getUIEventEmitter();
 	const chatCommandState: ChatCommandState = {
diff --git a/sdk/packages/core/src/extensions/computer-use/README.md b/sdk/packages/core/src/extensions/computer-use/README.md
new file mode 100644
index 0000000000..aae923418b
--- /dev/null
+++ b/sdk/packages/core/src/extensions/computer-use/README.md
@@ -0,0 +1,156 @@
+# Computer-use tool
+
+Bridges Anthropic's [computer-use tool](https://platform.claude.com/docs/en/agents-and-tools/tool-use/computer-use-tool)
+to an external screen-capture/input backend (developed out-of-tree, in Rust)
+over a small JSON-L socket protocol.
+
+This is a genuine `@cline/core` extension: `createComputerUseTool()` returns
+a plain `AgentTool`, the same contract used by every other tool in
+`sdk/packages/core/src/extensions/tools/`. Any host that builds a
+`CoreSessionConfig` (CLI, the VSCode adapter, a future standalone script,
+...) can add it via `config.extraTools` — see `createComputerUseToolFromEnv()`
+in `env.ts` for the zero-config way to opt in from `CLINE_COMPUTER_USE_PORT`.
+
+This folder is deliberately isolated from the rest of `@cline/core`:
+
+- It only imports `AgentTool`/`AgentToolContext`/`createTool` from
+  `@cline/shared`.
+- It has no dependency on MCP, the plugin-sandbox system, or any
+  host-specific services.
+
+This makes it straightforward to lift into a real out-of-tree Cline plugin
+later (see `sdk/packages/core/src/extensions/plugin/`) without touching call
+sites beyond wherever it's added to `extraTools`.
+
+## Why not MCP?
+
+MCP is Cline's real plugin/tool-integration mechanism, and it was
+considered. It was not used here because:
+
+- MCP requires a JSON-RPC 2.0 handshake (`initialize`/`initialized`),
+  capability negotiation, and a tool-discovery round trip before the first
+  real call can be made. None of that is useful for a single, fixed tool
+  (`computer`) talking to a single, purpose-built backend process.
+- MCP's transports (stdio framed messages, or SSE/HTTP) add either process
+  lifecycle management or an HTTP server to what is fundamentally a
+  low-latency "send an input event, get a screenshot back" loop, called on
+  essentially every model turn during a computer-use session.
+- MCP tool names get namespaced (`server__tool`) and go through the generic
+  `McpHub`/`createMcpTools` plumbing (see `sdk/packages/core/src/extensions/mcp/`),
+  which is the right call for arbitrary third-party servers but is extra
+  indirection for a first-party, tightly-coupled bridge.
+
+A direct socket client keeps the round-trip cost to "one write, one read"
+and keeps the protocol trivial to implement in Rust with just `tokio::net`
+and `serde_json` — no MCP SDK dependency needed on the Rust side. If/when
+this becomes a real out-of-tree plugin, it can still register as a normal
+`AgentTool` from a plugin's `setup()`; moving away from MCP was about
+avoiding protocol overhead, not about avoiding the plugin system.
+
+## Wire protocol
+
+- **Transport:** plain TCP to `127.0.0.1:<port>` (loopback only). TCP is used
+  instead of a Unix domain socket / Windows named pipe so the exact same
+  client code works unmodified on Windows, macOS, and Linux.
+- **Framing:** newline-delimited JSON ("JSON Lines" / JSON-L). Every request
+  or response is exactly one JSON value serialized on one line, terminated
+  by `\n`. No `Content-Length` headers, no multipart framing — this is the
+  simplest framing that still works correctly, since JSON string values
+  always escape embedded newlines.
+- **Multiplexing:** every request carries a numeric `id`; the backend must
+  echo it back on the matching response. The client does not assume
+  in-order responses.
+
+### Request (Cline -> backend)
+
+```jsonc
+{
+  "id": 1,
+  "action": "screenshot" | "cursor_position" | "mouse_move" | "left_click" |
+            "left_click_drag" | "right_click" | "middle_click" |
+            "double_click" | "triple_click" | "left_mouse_down" |
+            "left_mouse_up" | "key" | "hold_key" | "type" | "scroll" |
+            "wait" | "zoom" |
+            // Internal query, not one of Anthropic's `computer` tool
+            // actions. Sent once at startup to build the tool's
+            // description/schema with the real, native display size
+            // instead of a guessed default. See "Display size" below.
+            "get_display_info",
+  "coordinate": [x, y],            // optional, pixel coordinate
+  "startCoordinate": [x, y],       // optional, for left_click_drag
+  "text": "hello world",           // optional, for "type"
+  "keys": "ctrl+alt+delete",       // optional, for "key" / "hold_key"
+  "durationSeconds": 0.5,          // optional, for "hold_key" / "wait"
+  "scrollDirection": "down",       // optional, for "scroll"
+  "scrollAmount": 3,               // optional, for "scroll"
+  "region": [x, y, width, height]  // optional, for "zoom"
+}
+```
+
+### Response (backend -> Cline)
+
+```jsonc
+{
+  "id": 1,
+  "ok": true,
+  "text": "optional human-readable result (e.g. cursor position)",
+  "image": {                       // present for "screenshot" and any
+    "data": "<base64>",            // action that returns a fresh screenshot
+    "mediaType": "image/png"
+  },
+  "display": {                     // present for "get_display_info"
+    "widthPx": 1920,
+    "heightPx": 1080
+  }
+}
+```
+
+On failure:
+
+```jsonc
+{ "id": 1, "ok": false, "error": "description of what went wrong" }
+```
+
+See `protocol.ts` for the exact TypeScript types and `client.ts` for the
+client-side framing/pending-request implementation.
+
+## Display size
+
+The `computer` tool's description embeds the display's pixel dimensions,
+which Anthropic's model uses to reason about coordinates. Since the backend
+is the one actually capturing the screen, it — not Cline — is the source of
+truth for those dimensions.
+
+`createComputerUseTool()` is therefore `async`: unless both
+`displayWidthPx`/`displayHeightPx` are passed explicitly, it calls
+`ComputerUseClient.getDisplayInfo()` (a `"get_display_info"` request) once at
+construction time and uses the backend's reported size. A single override
+(e.g. only `displayWidthPx`) still queries the backend for the other
+dimension.
+
+## Opting in from environment variables
+
+`createComputerUseToolFromEnv()` (`env.ts`) returns a ready-to-use tool (or
+`undefined` if computer-use isn't configured for the current process) and is
+also `async` for the same reason:
+
+| Variable | Required | Default | Meaning |
+| --- | --- | --- | --- |
+| `CLINE_COMPUTER_USE_PORT` | yes (enables the tool) | — | Backend TCP port |
+| `CLINE_COMPUTER_USE_HOST` | no | `127.0.0.1` | Backend host |
+| `CLINE_COMPUTER_USE_DISPLAY_WIDTH` | no | queried from backend | Override display width, px |
+| `CLINE_COMPUTER_USE_DISPLAY_HEIGHT` | no | queried from backend | Override display height, px |
+
+## Not yet done
+
+- No auth/handshake — this assumes the backend is a locally-spawned trusted
+  process on loopback. Do not bind the backend to a non-loopback address.
+- No reconnect/backoff policy in the client; a dropped connection fails all
+  in-flight requests and reconnects lazily on the next call.
+- No persisted setting/UI toggle; env-var opt-in only, matching this being a
+  proof of concept.
+- The Anthropic `anthropic-beta: computer-use-2025-11-24` header is sent
+  unconditionally for the direct `anthropic` provider (see
+  `sdk/packages/llms/src/providers/routing/anthropic-compatible.ts`) rather
+  than gated on whether the `computer` tool is actually part of the current
+  request. Fine for this proof of concept; revisit before shipping.
diff --git a/sdk/packages/core/src/extensions/computer-use/client.test.ts b/sdk/packages/core/src/extensions/computer-use/client.test.ts
new file mode 100644
index 0000000000..06c0a36d10
--- /dev/null
+++ b/sdk/packages/core/src/extensions/computer-use/client.test.ts
@@ -0,0 +1,166 @@
+import { type AddressInfo, createServer, type Server, type Socket } from "node:net";
+import { afterEach, describe, expect, it } from "vitest";
+import { ComputerUseClient } from "./client";
+import type { ComputerUseResponse } from "./protocol";
+
+/**
+ * Minimal fake computer-use backend for tests: a real TCP server that reads
+ * newline-delimited JSON requests and replies according to `respond`.
+ */
+function startFakeBackend(
+	respond: (request: Record<string, unknown>) => ComputerUseResponse,
+): Promise<{ server: Server; port: number }> {
+	return new Promise((resolve) => {
+		const server = createServer((socket: Socket) => {
+			let buffer = "";
+			socket.setEncoding("utf8");
+			socket.on("data", (chunk: string) => {
+				buffer += chunk;
+				let newlineIndex = buffer.indexOf("\n");
+				while (newlineIndex >= 0) {
+					const line = buffer.slice(0, newlineIndex);
+					buffer = buffer.slice(newlineIndex + 1);
+					if (line.trim().length > 0) {
+						const request = JSON.parse(line) as Record<string, unknown>;
+						const response = respond(request);
+						socket.write(`${JSON.stringify(response)}\n`);
+					}
+					newlineIndex = buffer.indexOf("\n");
+				}
+			});
+		});
+		server.listen(0, "127.0.0.1", () => {
+			const address = server.address() as AddressInfo;
+			resolve({ server, port: address.port });
+		});
+	});
+}
+
+describe("ComputerUseClient", () => {
+	let server: Server | undefined;
+
+	afterEach(async () => {
+		if (!server) {
+			return;
+		}
+		await new Promise<void>((resolve) => server?.close(() => resolve()));
+	});
+
+	it("sends a request and resolves with the matching response", async () => {
+		const started = await startFakeBackend((request) => ({
+			id: request.id as number,
+			ok: true,
+			text: `handled ${request.action as string}`,
+		}));
+		server = started.server;
+
+		const client = new ComputerUseClient({ port: started.port });
+		const response = await client.send({ action: "screenshot" });
+
+		expect(response.ok).toBe(true);
+		expect(response.text).toBe("handled screenshot");
+		client.close();
+	});
+
+	it("matches responses to requests by id across multiple in-flight calls", async () => {
+		const started = await startFakeBackend((request) => ({
+			id: request.id as number,
+			ok: true,
+			text: `id=${request.id}`,
+		}));
+		server = started.server;
+
+		const client = new ComputerUseClient({ port: started.port });
+		const [first, second] = await Promise.all([
+			client.send({ action: "cursor_position" }),
+			client.send({ action: "screenshot" }),
+		]);
+
+		expect(first.text).toBe("id=1");
+		expect(second.text).toBe("id=2");
+		client.close();
+	});
+
+	it("surfaces backend error responses", async () => {
+		const started = await startFakeBackend((request) => ({
+			id: request.id as number,
+			ok: false,
+			error: "backend exploded",
+		}));
+		server = started.server;
+
+		const client = new ComputerUseClient({ port: started.port });
+		const response = await client.send({ action: "left_click", coordinate: [1, 2] });
+
+		expect(response.ok).toBe(false);
+		expect(response.error).toBe("backend exploded");
+		client.close();
+	});
+
+	it("getDisplayInfo resolves with the backend-reported dimensions", async () => {
+		const started = await startFakeBackend((request) => ({
+			id: request.id as number,
+			ok: true,
+			display: { widthPx: 1920, heightPx: 1080 },
+		}));
+		server = started.server;
+
+		const client = new ComputerUseClient({ port: started.port });
+		const info = await client.getDisplayInfo();
+
+		expect(info).toEqual({ widthPx: 1920, heightPx: 1080 });
+		client.close();
+	});
+
+	it("getDisplayInfo rejects when the backend omits display info", async () => {
+		const started = await startFakeBackend((request) => ({
+			id: request.id as number,
+			ok: true,
+		}));
+		server = started.server;
+
+		const client = new ComputerUseClient({ port: started.port });
+		await expect(client.getDisplayInfo()).rejects.toThrow();
+		client.close();
+	});
+
+	it("rejects when connecting to a closed port", async () => {
+		const started = await startFakeBackend((request) => ({
+			id: request.id as number,
+			ok: true,
+		}));
+		server = started.server;
+		const { port } = started;
+		const startedServer = started.server;
+		await new Promise<void>((resolve) => startedServer.close(() => resolve()));
+
+		const client = new ComputerUseClient({
+			port,
+			connectTimeoutMs: 500,
+		});
+		await expect(client.send({ action: "screenshot" })).rejects.toThrow();
+	});
+
+	it("times out a request the backend never answers", async () => {
+		const started = await startFakeBackend(() => {
+			throw new Error("never called: server intentionally does not respond");
+		});
+		server = started.server;
+		// Override respond to swallow requests without answering.
+		server.removeAllListeners("connection");
+		server.on("connection", (socket) => {
+			socket.on("data", () => {
+				/* intentionally never respond */
+			});
+		});
+
+		const client = new ComputerUseClient({
+			port: started.port,
+			requestTimeoutMs: 200,
+		});
+		await expect(client.send({ action: "wait", durationSeconds: 1 })).rejects.toThrow(
+			/timed out/,
+		);
+		client.close();
+	});
+});
diff --git a/sdk/packages/core/src/extensions/computer-use/client.ts b/sdk/packages/core/src/extensions/computer-use/client.ts
new file mode 100644
index 0000000000..17965688f2
--- /dev/null
+++ b/sdk/packages/core/src/extensions/computer-use/client.ts
@@ -0,0 +1,200 @@
+import { type Socket, connect } from "node:net";
+import {
+	type ComputerUseDisplayInfo,
+	GET_DISPLAY_INFO_ACTION,
+	type ComputerUseRequest,
+	type ComputerUseResponse,
+	isComputerUseResponse,
+} from "./protocol";
+
+export interface ComputerUseClientOptions {
+	/** Backend host, defaults to loopback only. */
+	host?: string;
+	/** Backend TCP port. */
+	port: number;
+	/** Per-request timeout in milliseconds. */
+	requestTimeoutMs?: number;
+	/** Timeout for establishing the initial connection, in milliseconds. */
+	connectTimeoutMs?: number;
+}
+
+const DEFAULT_REQUEST_TIMEOUT_MS = 15_000;
+const DEFAULT_CONNECT_TIMEOUT_MS = 3_000;
+
+interface PendingRequest {
+	resolve: (response: ComputerUseResponse) => void;
+	reject: (error: Error) => void;
+	timeout: ReturnType<typeof setTimeout>;
+}
+
+/**
+ * Minimal client for the computer-use backend's JSON-L-over-TCP protocol.
+ *
+ * Deliberately lightweight: no reconnect/backoff policy, no multiplexed
+ * transport negotiation, no schema registry. Connects lazily on first use,
+ * reuses the connection across calls, and reconnects on the next call after
+ * a disconnect. See ./protocol.ts for the wire format and the rationale for
+ * not using MCP here.
+ */
+export class ComputerUseClient {
+	private socket: Socket | undefined;
+	private connectPromise: Promise<Socket> | undefined;
+	private buffer = "";
+	private nextRequestId = 1;
+	private readonly pending = new Map<number, PendingRequest>();
+
+	constructor(private readonly options: ComputerUseClientOptions) {}
+
+	/** Sends a request and resolves with the matching response. */
+	async send(
+		request: Omit<ComputerUseRequest, "id">,
+	): Promise<ComputerUseResponse> {
+		const socket = await this.ensureConnected();
+		const id = this.nextRequestId++;
+		const fullRequest: ComputerUseRequest = { ...request, id };
+		const line = `${JSON.stringify(fullRequest)}\n`;
+
+		const timeoutMs = this.options.requestTimeoutMs ?? DEFAULT_REQUEST_TIMEOUT_MS;
+		return new Promise<ComputerUseResponse>((resolve, reject) => {
+			const timeout = setTimeout(() => {
+				this.pending.delete(id);
+				reject(
+					new Error(
+						`Computer-use request ${id} (${request.action}) timed out after ${timeoutMs}ms`,
+					),
+				);
+			}, timeoutMs);
+
+			this.pending.set(id, { resolve, reject, timeout });
+
+			socket.write(line, (error) => {
+				if (error) {
+					this.pending.delete(id);
+					clearTimeout(timeout);
+					reject(error);
+				}
+			});
+		});
+	}
+
+	/**
+	 * Queries the backend for the native display dimensions. This is not one
+	 * of Anthropic's `computer` tool actions — it's a one-time startup query
+	 * used to build the tool's description/schema with real values instead
+	 * of guessed defaults, since the tool's definition is static once built.
+	 */
+	async getDisplayInfo(): Promise<ComputerUseDisplayInfo> {
+		const response = await this.send({ action: GET_DISPLAY_INFO_ACTION });
+		if (!response.ok || !response.display) {
+			throw new Error(
+				response.error ?? "Computer-use backend did not return display info",
+			);
+		}
+		return response.display;
+	}
+
+	/** Closes the underlying socket, if any. Safe to call multiple times. */
+	close(): void {
+		this.socket?.destroy();
+		this.socket = undefined;
+		this.connectPromise = undefined;
+		this.failAllPending(new Error("Computer-use client closed"));
+	}
+
+	private async ensureConnected(): Promise<Socket> {
+		if (this.socket && !this.socket.destroyed) {
+			return this.socket;
+		}
+		if (!this.connectPromise) {
+			this.connectPromise = this.connectSocket();
+		}
+		return this.connectPromise;
+	}
+
+	private connectSocket(): Promise<Socket> {
+		const host = this.options.host ?? "127.0.0.1";
+		const port = this.options.port;
+		const connectTimeoutMs =
+			this.options.connectTimeoutMs ?? DEFAULT_CONNECT_TIMEOUT_MS;
+
+		return new Promise<Socket>((resolve, reject) => {
+			const socket = connect({ host, port });
+			const onConnectTimeout = setTimeout(() => {
+				socket.destroy();
+				reject(
+					new Error(
+						`Timed out connecting to computer-use backend at ${host}:${port}`,
+					),
+				);
+			}, connectTimeoutMs);
+
+			socket.once("connect", () => {
+				clearTimeout(onConnectTimeout);
+				this.socket = socket;
+				this.buffer = "";
+				// Don't let an idle backend connection keep the host process
+				// alive on its own; the socket is reference-counted back in
+				// while a request is in flight via the write/response cycle.
+				socket.unref();
+				resolve(socket);
+			});
+
+			socket.once("error", (error) => {
+				clearTimeout(onConnectTimeout);
+				this.connectPromise = undefined;
+				this.failAllPending(error);
+				reject(error);
+			});
+
+			socket.once("close", () => {
+				this.connectPromise = undefined;
+				this.failAllPending(new Error("Computer-use backend connection closed"));
+			});
+
+			socket.setEncoding("utf8");
+			socket.on("data", (chunk: string) => this.onData(chunk));
+		});
+	}
+
+	private onData(chunk: string): void {
+		this.buffer += chunk;
+		let newlineIndex = this.buffer.indexOf("\n");
+		while (newlineIndex >= 0) {
+			const line = this.buffer.slice(0, newlineIndex).trim();
+			this.buffer = this.buffer.slice(newlineIndex + 1);
+			if (line.length > 0) {
+				this.handleLine(line);
+			}
+			newlineIndex = this.buffer.indexOf("\n");
+		}
+	}
+
+	private handleLine(line: string): void {
+		let parsed: unknown;
+		try {
+			parsed = JSON.parse(line);
+		} catch {
+			// Malformed line from the backend; ignore rather than crash the
+			// connection, since this is best-effort POC plumbing.
+			return;
+		}
+		if (!isComputerUseResponse(parsed)) {
+			return;
+		}
+		const pending = this.pending.get(parsed.id);
+		if (!pending) {
+			return;
+		}
+		this.pending.delete(parsed.id);
+		clearTimeout(pending.timeout);
+		pending.resolve(parsed);
+	}
+
+	private failAllPending(error: Error): void {
+		for (const [id, pending] of this.pending) {
+			clearTimeout(pending.timeout);
+			pending.reject(error);
+			this.pending.delete(id);
+		}
+	}
+}
diff --git a/sdk/packages/core/src/extensions/computer-use/env.test.ts b/sdk/packages/core/src/extensions/computer-use/env.test.ts
new file mode 100644
index 0000000000..095f811beb
--- /dev/null
+++ b/sdk/packages/core/src/extensions/computer-use/env.test.ts
@@ -0,0 +1,122 @@
+import { type AddressInfo, createServer, type Server, type Socket } from "node:net";
+import { afterEach, describe, expect, it } from "vitest";
+import { createComputerUseToolFromEnv } from "./env";
+import type { ComputerUseResponse } from "./protocol";
+
+/**
+ * Like the fake backend in client.test.ts/tool.test.ts, but also tracks
+ * accepted sockets so the test can force-close them. Unlike those files,
+ * `createComputerUseToolFromEnv` builds its own internal `ComputerUseClient`
+ * with no handle exposed back to the test, so there's no `client.close()` to
+ * call — `server.close()` alone would otherwise hang forever waiting for the
+ * (unref'd but still open) client connection to end.
+ */
+function startFakeBackend(
+	respond: (request: Record<string, unknown>) => ComputerUseResponse,
+): Promise<{ server: Server; port: number; destroyConnections: () => void }> {
+	const sockets = new Set<Socket>();
+	return new Promise((resolve) => {
+		const server = createServer((socket: Socket) => {
+			sockets.add(socket);
+			socket.on("close", () => sockets.delete(socket));
+			let buffer = "";
+			socket.setEncoding("utf8");
+			socket.on("data", (chunk: string) => {
+				buffer += chunk;
+				let newlineIndex = buffer.indexOf("\n");
+				while (newlineIndex >= 0) {
+					const line = buffer.slice(0, newlineIndex);
+					buffer = buffer.slice(newlineIndex + 1);
+					if (line.trim().length > 0) {
+						const request = JSON.parse(line) as Record<string, unknown>;
+						socket.write(`${JSON.stringify(respond(request))}\n`);
+					}
+					newlineIndex = buffer.indexOf("\n");
+				}
+			});
+		});
+		server.listen(0, "127.0.0.1", () => {
+			const address = server.address() as AddressInfo;
+			resolve({
+				server,
+				port: address.port,
+				destroyConnections: () => {
+					for (const socket of sockets) {
+						socket.destroy();
+					}
+				},
+			});
+		});
+	});
+}
+
+function fakeDisplayInfoBackend(
+	widthPx: number,
+	heightPx: number,
+): (request: Record<string, unknown>) => ComputerUseResponse {
+	return (request) => ({
+		id: request.id as number,
+		ok: true,
+		display: { widthPx, heightPx },
+	});
+}
+
+describe("createComputerUseToolFromEnv", () => {
+	let server: Server | undefined;
+	let destroyConnections: (() => void) | undefined;
+
+	afterEach(async () => {
+		destroyConnections?.();
+		destroyConnections = undefined;
+		if (!server) {
+			return;
+		}
+		await new Promise<void>((resolve) => server?.close(() => resolve()));
+		server = undefined;
+	});
+
+	it("returns undefined when the port variable is unset", async () => {
+		await expect(createComputerUseToolFromEnv({})).resolves.toBeUndefined();
+	});
+
+	it("returns undefined when the port variable is not a positive integer", async () => {
+		await expect(
+			createComputerUseToolFromEnv({ CLINE_COMPUTER_USE_PORT: "not-a-port" }),
+		).resolves.toBeUndefined();
+		await expect(
+			createComputerUseToolFromEnv({ CLINE_COMPUTER_USE_PORT: "0" }),
+		).resolves.toBeUndefined();
+		await expect(
+			createComputerUseToolFromEnv({ CLINE_COMPUTER_USE_PORT: "-1" }),
+		).resolves.toBeUndefined();
+	});
+
+	it("queries the backend for display size when no override is set", async () => {
+		const started = await startFakeBackend(fakeDisplayInfoBackend(1920, 1080));
+		server = started.server;
+		destroyConnections = started.destroyConnections;
+
+		const tool = await createComputerUseToolFromEnv({
+			CLINE_COMPUTER_USE_PORT: String(started.port),
+		});
+
+		expect(tool).toBeDefined();
+		expect(tool?.name).toBe("computer");
+		expect(tool?.description).toContain("1920x1080");
+	});
+
+	it("honors display size overrides without querying the backend", async () => {
+		const started = await startFakeBackend(() => {
+			throw new Error("backend should not be queried when overrides are set");
+		});
+		server = started.server;
+
+		const tool = await createComputerUseToolFromEnv({
+			CLINE_COMPUTER_USE_PORT: String(started.port),
+			CLINE_COMPUTER_USE_DISPLAY_WIDTH: "1024",
+			CLINE_COMPUTER_USE_DISPLAY_HEIGHT: "768",
+		});
+
+		expect(tool?.description).toContain("1024x768");
+	});
+});
diff --git a/sdk/packages/core/src/extensions/computer-use/env.ts b/sdk/packages/core/src/extensions/computer-use/env.ts
new file mode 100644
index 0000000000..9f8a7335e7
--- /dev/null
+++ b/sdk/packages/core/src/extensions/computer-use/env.ts
@@ -0,0 +1,43 @@
+import type { AgentTool } from "@cline/shared";
+import { createComputerUseTool } from "./tool";
+
+const PORT_ENV_VAR = "CLINE_COMPUTER_USE_PORT";
+const HOST_ENV_VAR = "CLINE_COMPUTER_USE_HOST";
+const DISPLAY_WIDTH_ENV_VAR = "CLINE_COMPUTER_USE_DISPLAY_WIDTH";
+const DISPLAY_HEIGHT_ENV_VAR = "CLINE_COMPUTER_USE_DISPLAY_HEIGHT";
+
+function parsePositiveInt(value: string | undefined): number | undefined {
+	if (!value) {
+		return undefined;
+	}
+	const parsed = Number.parseInt(value, 10);
+	return Number.isFinite(parsed) && parsed > 0 ? parsed : undefined;
+}
+
+/**
+ * Builds the `computer` tool from environment variables, or returns
+ * `undefined` if computer-use isn't configured for this process.
+ *
+ * This is a proof-of-concept convenience for hosts (starting with the CLI)
+ * that want to opt in without any config plumbing of their own: set
+ * `CLINE_COMPUTER_USE_PORT` to the backend's TCP port and the tool becomes
+ * available. Display size is queried from the backend by default; the
+ * `CLINE_COMPUTER_USE_DISPLAY_WIDTH`/`_HEIGHT` variables only need to be set
+ * to override that. There is intentionally no persisted setting/toggle yet
+ * — see ./README.md.
+ */
+export async function createComputerUseToolFromEnv(
+	env: NodeJS.ProcessEnv = process.env,
+): Promise<AgentTool | undefined> {
+	const port = parsePositiveInt(env[PORT_ENV_VAR]);
+	if (!port) {
+		return undefined;
+	}
+
+	return createComputerUseTool({
+		host: env[HOST_ENV_VAR] || undefined,
+		port,
+		displayWidthPx: parsePositiveInt(env[DISPLAY_WIDTH_ENV_VAR]),
+		displayHeightPx: parsePositiveInt(env[DISPLAY_HEIGHT_ENV_VAR]),
+	});
+}
diff --git a/sdk/packages/core/src/extensions/computer-use/index.ts b/sdk/packages/core/src/extensions/computer-use/index.ts
new file mode 100644
index 0000000000..979bf31ef8
--- /dev/null
+++ b/sdk/packages/core/src/extensions/computer-use/index.ts
@@ -0,0 +1,24 @@
+/**
+ * Computer-use tool integration.
+ *
+ * A genuine `@cline/core` extension (an `AgentTool`, usable via
+ * `CoreSessionConfig.extraTools` from any host), kept in its own folder with
+ * a minimal dependency surface (`@cline/shared` types only) so it can be
+ * extracted into a standalone Cline plugin later with minimal changes. See
+ * ./protocol.ts for the wire format and ./README.md for the backend
+ * contract and design rationale.
+ */
+export { ComputerUseClient, type ComputerUseClientOptions } from "./client";
+export {
+	createComputerUseToolFromEnv,
+} from "./env";
+export type {
+	ComputerUseAction,
+	ComputerUseCoordinate,
+	ComputerUseDisplayInfo,
+	ComputerUseImage,
+	ComputerUseRequest,
+	ComputerUseResponse,
+} from "./protocol";
+export { GET_DISPLAY_INFO_ACTION, isComputerUseResponse } from "./protocol";
+export { createComputerUseTool, type ComputerUseToolOptions } from "./tool";
diff --git a/sdk/packages/core/src/extensions/computer-use/protocol.ts b/sdk/packages/core/src/extensions/computer-use/protocol.ts
new file mode 100644
index 0000000000..df3c399352
--- /dev/null
+++ b/sdk/packages/core/src/extensions/computer-use/protocol.ts
@@ -0,0 +1,121 @@
+/**
+ * Wire protocol for the Cline <-> computer-use backend socket connection.
+ *
+ * This is intentionally NOT MCP. The computer-use backend (a Rust process,
+ * developed out-of-tree) is a single-purpose, low-latency screen/input
+ * bridge: connect once, send an action, get a screenshot back. MCP's
+ * JSON-RPC 2.0 handshake, capability negotiation, and stdio/SSE transport
+ * machinery buy nothing here and add real latency + complexity for a tool
+ * that's called on every turn of an agentic loop. A plain newline-delimited
+ * JSON ("JSON Lines" / JSON-L) socket protocol keeps the dependency light
+ * and easy to reimplement in Rust with nothing more than `tokio::net` +
+ * `serde_json`.
+ *
+ * Framing: every message is a single JSON value serialized on one line,
+ * terminated by "\n". No Content-Length headers, no multipart framing.
+ * Newlines inside string values MUST be JSON-escaped (this is automatic with
+ * `JSON.stringify`/`serde_json::to_string`), so a bare "\n" always marks a
+ * message boundary.
+ *
+ * Transport: plain TCP, localhost only. TCP (rather than a Unix domain
+ * socket / Windows named pipe) is used so the same client code works
+ * unmodified on Windows, macOS, and Linux. This is a local trust boundary
+ * (loopback only, never bound to 0.0.0.0).
+ */
+
+/**
+ * Actions understood by the computer-use backend, mirroring Anthropic's
+ * `computer` tool action set (see
+ * https://platform.claude.com/docs/en/agents-and-tools/tool-use/computer-use-tool).
+ */
+export type ComputerUseAction =
+	| "screenshot"
+	| "cursor_position"
+	| "mouse_move"
+	| "left_click"
+	| "left_click_drag"
+	| "right_click"
+	| "middle_click"
+	| "double_click"
+	| "triple_click"
+	| "left_mouse_down"
+	| "left_mouse_up"
+	| "key"
+	| "hold_key"
+	| "type"
+	| "scroll"
+	| "wait"
+	| "zoom";
+
+/**
+ * Internal query (not one of Anthropic's `computer` tool actions) used to
+ * ask the backend for the real, native display dimensions before the
+ * `computer` tool is built. The tool's description/schema is static once
+ * built, so this must be resolved once at startup rather than per model
+ * turn — see `ComputerUseClient.getDisplayInfo()`.
+ */
+export const GET_DISPLAY_INFO_ACTION = "get_display_info";
+
+/** Native display dimensions reported by the backend. */
+export interface ComputerUseDisplayInfo {
+	widthPx: number;
+	heightPx: number;
+}
+
+/** A single [x, y] pixel coordinate in the (possibly scaled) display space. */
+export type ComputerUseCoordinate = readonly [number, number];
+
+/** Request envelope sent from Cline to the computer-use backend, one per line. */
+export interface ComputerUseRequest {
+	/** Monotonically increasing id used to match responses to requests. */
+	id: number;
+	action: ComputerUseAction | typeof GET_DISPLAY_INFO_ACTION;
+	coordinate?: ComputerUseCoordinate;
+	startCoordinate?: ComputerUseCoordinate;
+	text?: string;
+	/** Key name(s) for "key"/"hold_key", e.g. "ctrl+alt+delete". */
+	keys?: string;
+	/** Duration in seconds, used by "hold_key" and "wait". */
+	durationSeconds?: number;
+	scrollDirection?: "up" | "down" | "left" | "right";
+	scrollAmount?: number;
+	/** Region [x, y, width, height] for "zoom". */
+	region?: readonly [number, number, number, number];
+}
+
+/** A single image returned by the backend (typically a screenshot). */
+export interface ComputerUseImage {
+	/** Base64-encoded image bytes. */
+	data: string;
+	/** MIME type, e.g. "image/png". */
+	mediaType: string;
+}
+
+/** Response envelope received from the computer-use backend, one per line. */
+export interface ComputerUseResponse {
+	/** Echoes the request id this response answers. */
+	id: number;
+	ok: boolean;
+	/** Human-readable result text (e.g. cursor position, ack message). */
+	text?: string;
+	/**
+	 * Present for actions that capture the screen ("screenshot", and
+	 * optionally others that return a post-action screenshot).
+	 */
+	image?: ComputerUseImage;
+	/** Present in the response to a "get_display_info" request. */
+	display?: ComputerUseDisplayInfo;
+	/** Present when ok is false. */
+	error?: string;
+}
+
+/** Type guard for parsed JSON-L lines from the backend. */
+export function isComputerUseResponse(
+	value: unknown,
+): value is ComputerUseResponse {
+	if (!value || typeof value !== "object") {
+		return false;
+	}
+	const candidate = value as Record<string, unknown>;
+	return typeof candidate.id === "number" && typeof candidate.ok === "boolean";
+}
diff --git a/sdk/packages/core/src/extensions/computer-use/tool.test.ts b/sdk/packages/core/src/extensions/computer-use/tool.test.ts
new file mode 100644
index 0000000000..e7cdc1f3c9
--- /dev/null
+++ b/sdk/packages/core/src/extensions/computer-use/tool.test.ts
@@ -0,0 +1,204 @@
+import type { AgentToolContext } from "@cline/shared";
+import { type AddressInfo, createServer, type Server, type Socket } from "node:net";
+import { afterEach, describe, expect, it } from "vitest";
+import { ComputerUseClient } from "./client";
+import type { ComputerUseResponse } from "./protocol";
+import { createComputerUseTool } from "./tool";
+
+function startFakeBackend(
+	respond: (request: Record<string, unknown>) => ComputerUseResponse,
+): Promise<{ server: Server; port: number }> {
+	return new Promise((resolve) => {
+		const server = createServer((socket: Socket) => {
+			let buffer = "";
+			socket.setEncoding("utf8");
+			socket.on("data", (chunk: string) => {
+				buffer += chunk;
+				let newlineIndex = buffer.indexOf("\n");
+				while (newlineIndex >= 0) {
+					const line = buffer.slice(0, newlineIndex);
+					buffer = buffer.slice(newlineIndex + 1);
+					if (line.trim().length > 0) {
+						const request = JSON.parse(line) as Record<string, unknown>;
+						socket.write(`${JSON.stringify(respond(request))}\n`);
+					}
+					newlineIndex = buffer.indexOf("\n");
+				}
+			});
+		});
+		server.listen(0, "127.0.0.1", () => {
+			const address = server.address() as AddressInfo;
+			resolve({ server, port: address.port });
+		});
+	});
+}
+
+const ctx: AgentToolContext = {
+	agentId: "agent-1",
+	conversationId: "conv-1",
+	iteration: 1,
+};
+
+describe("createComputerUseTool", () => {
+	let server: Server | undefined;
+	let client: ComputerUseClient | undefined;
+
+	afterEach(async () => {
+		client?.close();
+		client = undefined;
+		if (!server) {
+			return;
+		}
+		await new Promise<void>((resolve) => server?.close(() => resolve()));
+		server = undefined;
+	});
+
+	it("exposes the computer tool name and an object input schema", async () => {
+		const started = await startFakeBackend((request) => ({
+			id: request.id as number,
+			ok: true,
+		}));
+		server = started.server;
+		client = new ComputerUseClient({ port: started.port });
+
+		const tool = await createComputerUseTool({
+			port: started.port,
+			displayWidthPx: 1024,
+			displayHeightPx: 768,
+			client,
+		});
+
+		expect(tool.name).toBe("computer");
+		expect(tool.inputSchema.type).toBe("object");
+		expect(tool.description).toContain("1024x768");
+	});
+
+	it("queries the backend for display size when no override is provided", async () => {
+		const started = await startFakeBackend((request) => ({
+			id: request.id as number,
+			ok: true,
+			display: { widthPx: 1920, heightPx: 1080 },
+		}));
+		server = started.server;
+		client = new ComputerUseClient({ port: started.port });
+
+		const tool = await createComputerUseTool({
+			port: started.port,
+			client,
+		});
+
+		expect(tool.description).toContain("1920x1080");
+	});
+
+	it("uses a single override without querying the backend for the other dimension", async () => {
+		const started = await startFakeBackend((request) => ({
+			id: request.id as number,
+			ok: true,
+			display: { widthPx: 1920, heightPx: 1080 },
+		}));
+		server = started.server;
+		client = new ComputerUseClient({ port: started.port });
+
+		const tool = await createComputerUseTool({
+			port: started.port,
+			displayWidthPx: 640,
+			client,
+		});
+
+		expect(tool.description).toContain("640x1080");
+	});
+
+	it("returns a screenshot as multimodal text+image content", async () => {
+		const started = await startFakeBackend((request) => ({
+			id: request.id as number,
+			ok: true,
+			text: "screenshot taken",
+			image: { data: "ZmFrZS1wbmc=", mediaType: "image/png" },
+		}));
+		server = started.server;
+		client = new ComputerUseClient({ port: started.port });
+
+		const tool = await createComputerUseTool({
+			port: started.port,
+			displayWidthPx: 1024,
+			displayHeightPx: 768,
+			client,
+		});
+
+		const result = await tool.execute({ action: "screenshot" }, ctx);
+
+		expect(result).toEqual([
+			{ type: "text", text: "screenshot taken" },
+			{ type: "image", data: "ZmFrZS1wbmc=", mediaType: "image/png" },
+		]);
+	});
+
+	it("returns plain text when the backend does not return an image", async () => {
+		const started = await startFakeBackend((request) => ({
+			id: request.id as number,
+			ok: true,
+			text: "clicked at (10, 20)",
+		}));
+		server = started.server;
+		client = new ComputerUseClient({ port: started.port });
+
+		const tool = await createComputerUseTool({
+			port: started.port,
+			displayWidthPx: 1024,
+			displayHeightPx: 768,
+			client,
+		});
+
+		const result = await tool.execute(
+			{ action: "left_click", coordinate: [10, 20] },
+			ctx,
+		);
+
+		expect(result).toBe("clicked at (10, 20)");
+	});
+
+	it("maps key/hold_key text into the keys field, not the text field", async () => {
+		const started = await startFakeBackend((request) => ({
+			id: request.id as number,
+			ok: true,
+			text: `keys=${request.keys ?? "none"} text=${request.text ?? "none"}`,
+		}));
+		server = started.server;
+		client = new ComputerUseClient({ port: started.port });
+
+		const tool = await createComputerUseTool({
+			port: started.port,
+			displayWidthPx: 1024,
+			displayHeightPx: 768,
+			client,
+		});
+
+		const result = await tool.execute(
+			{ action: "key", text: "ctrl+alt+delete" },
+			ctx,
+		);
+
+		expect(result).toBe("keys=ctrl+alt+delete text=none");
+	});
+
+	it("throws with the backend error message on failure", async () => {
+		const started = await startFakeBackend((request) => ({
+			id: request.id as number,
+			ok: false,
+			error: "no display attached",
+		}));
+		server = started.server;
+		client = new ComputerUseClient({ port: started.port });
+
+		const tool = await createComputerUseTool({
+			port: started.port,
+			displayWidthPx: 1024,
+			displayHeightPx: 768,
+			client,
+		});
+
+		await expect(tool.execute({ action: "screenshot" }, ctx)).rejects.toThrow(
+			"no display attached",
+		);
+	});
+});
diff --git a/sdk/packages/core/src/extensions/computer-use/tool.ts b/sdk/packages/core/src/extensions/computer-use/tool.ts
new file mode 100644
index 0000000000..512e7c6620
--- /dev/null
+++ b/sdk/packages/core/src/extensions/computer-use/tool.ts
@@ -0,0 +1,192 @@
+import { createTool } from "@cline/shared";
+import type { AgentTool, AgentToolContext } from "@cline/shared";
+import { ComputerUseClient, type ComputerUseClientOptions } from "./client";
+import type { ComputerUseAction, ComputerUseCoordinate } from "./protocol";
+
+export interface ComputerUseToolOptions extends ComputerUseClientOptions {
+	/**
+	 * Override for the controlled display's width in pixels, reported in the
+	 * tool description. When omitted, this is queried from the backend at
+	 * construction time via `ComputerUseClient.getDisplayInfo()` — the
+	 * backend is the source of truth for the real, native screen size.
+	 */
+	displayWidthPx?: number;
+	/** Override for display height in pixels. See `displayWidthPx`. */
+	displayHeightPx?: number;
+	/**
+	 * Optional pre-built client. Mainly useful for tests and for hosts that
+	 * want explicit control over the connection's lifecycle (e.g. calling
+	 * `client.close()` on shutdown). When omitted, a client is constructed
+	 * from the other options.
+	 */
+	client?: ComputerUseClient;
+}
+
+/** Raw tool input shape as sent by the model (mirrors Anthropic's `computer` tool). */
+interface ComputerToolInput {
+	action: ComputerUseAction;
+	coordinate?: ComputerUseCoordinate;
+	start_coordinate?: ComputerUseCoordinate;
+	text?: string;
+	duration?: number;
+	scroll_direction?: "up" | "down" | "left" | "right";
+	scroll_amount?: number;
+	region?: readonly [number, number, number, number];
+}
+
+const COMPUTER_TOOL_NAME = "computer";
+
+const COMPUTER_TOOL_INPUT_SCHEMA: Record<string, unknown> = {
+	type: "object",
+	properties: {
+		action: {
+			type: "string",
+			enum: [
+				"screenshot",
+				"cursor_position",
+				"mouse_move",
+				"left_click",
+				"left_click_drag",
+				"right_click",
+				"middle_click",
+				"double_click",
+				"triple_click",
+				"left_mouse_down",
+				"left_mouse_up",
+				"key",
+				"hold_key",
+				"type",
+				"scroll",
+				"wait",
+				"zoom",
+			],
+			description: "The action to perform.",
+		},
+		coordinate: {
+			type: "array",
+			items: { type: "number" },
+			minItems: 2,
+			maxItems: 2,
+			description:
+				"(x, y) pixel coordinate, required for mouse_move, left_click, left_click_drag (end point), right_click, middle_click, double_click, triple_click, left_mouse_down, left_mouse_up, and scroll (scroll origin).",
+		},
+		start_coordinate: {
+			type: "array",
+			items: { type: "number" },
+			minItems: 2,
+			maxItems: 2,
+			description: "(x, y) start coordinate, required for left_click_drag.",
+		},
+		text: {
+			type: "string",
+			description:
+				"Text to type (for the type action) or key combination to press (for key/hold_key, e.g. 'ctrl+alt+delete').",
+		},
+		duration: {
+			type: "number",
+			description: "Duration in seconds, used by hold_key and wait.",
+		},
+		scroll_direction: {
+			type: "string",
+			enum: ["up", "down", "left", "right"],
+			description: "Direction to scroll, required for the scroll action.",
+		},
+		scroll_amount: {
+			type: "number",
+			description: "Number of scroll clicks, required for the scroll action.",
+		},
+		region: {
+			type: "array",
+			items: { type: "number" },
+			minItems: 4,
+			maxItems: 4,
+			description:
+				"(x, y, width, height) region to zoom into, required for the zoom action.",
+		},
+	},
+	required: ["action"],
+};
+
+function toComputerUseRequest(input: ComputerToolInput) {
+	return {
+		action: input.action,
+		coordinate: input.coordinate,
+		startCoordinate: input.start_coordinate,
+		text: input.text,
+		durationSeconds: input.duration,
+		scrollDirection: input.scroll_direction,
+		scrollAmount: input.scroll_amount,
+		region: input.region,
+	};
+}
+
+/**
+ * Builds the `computer` tool that forwards Anthropic computer-use tool calls
+ * to an external, lightweight backend (a Rust process developed out-of-tree)
+ * over a plain JSON-L TCP socket.
+ *
+ * This is async because the tool's description embeds the display size,
+ * which is queried from the backend (the source of truth for the real,
+ * native screen dimensions) unless both `displayWidthPx`/`displayHeightPx`
+ * are explicitly overridden in `options`.
+ *
+ * This is a genuine `@cline/core` `AgentTool` — usable from any host that
+ * builds a `CoreSessionConfig` (CLI, VSCode adapter, etc.) via
+ * `config.extraTools`. It's deliberately isolated within its own folder
+ * (only depends on `@cline/shared`'s `AgentTool` contract) so it can be
+ * lifted out into a standalone Cline plugin later with minimal changes. See
+ * ./README.md for the wire protocol and rationale.
+ */
+export async function createComputerUseTool(
+	options: ComputerUseToolOptions,
+): Promise<AgentTool> {
+	const client = options.client ?? new ComputerUseClient(options);
+
+	const { displayWidthPx, displayHeightPx } =
+		options.displayWidthPx !== undefined && options.displayHeightPx !== undefined
+			? { displayWidthPx: options.displayWidthPx, displayHeightPx: options.displayHeightPx }
+			: await client.getDisplayInfo().then((info) => ({
+					displayWidthPx: options.displayWidthPx ?? info.widthPx,
+					displayHeightPx: options.displayHeightPx ?? info.heightPx,
+				}));
+
+	return createTool({
+		name: COMPUTER_TOOL_NAME,
+		description:
+			`Control the screen and keyboard/mouse of a remote computer environment. ` +
+			`The display is ${displayWidthPx}x${displayHeightPx} pixels. ` +
+			`Use "screenshot" to see the current screen before acting, since the environment ` +
+			`may change between turns. Coordinates are [x, y] pixels from the top-left corner.`,
+		inputSchema: COMPUTER_TOOL_INPUT_SCHEMA,
+		// Screenshots and round trips to an external process are slower than
+		// in-process tools; give this more room than the SDK's 30s default.
+		timeoutMs: 30_000,
+		retryable: false,
+		execute: async (input: unknown, _context: AgentToolContext) => {
+			const parsedInput = input as ComputerToolInput;
+			const response = await client.send(toComputerUseRequest(parsedInput));
+
+			if (!response.ok) {
+				throw new Error(
+					response.error ?? `Computer-use action "${parsedInput.action}" failed`,
+				);
+			}
+
+			if (!response.image) {
+				return response.text ?? `Action "${parsedInput.action}" completed.`;
+			}
+
+			return [
+				{
+					type: "text" as const,
+					text: response.text ?? `Action "${parsedInput.action}" completed.`,
+				},
+				{
+					type: "image" as const,
+					data: response.image.data,
+					mediaType: response.image.mediaType,
+				},
+			];
+		},
+	});
+}
diff --git a/sdk/packages/core/src/index.ts b/sdk/packages/core/src/index.ts
index b29d7a9cee..fb97f92241 100644
--- a/sdk/packages/core/src/index.ts
+++ b/sdk/packages/core/src/index.ts
@@ -1042,6 +1042,21 @@ export {
 export * from "./remote/remote-environments";
 export { ensureLoginShellPath } from "./remote/shell-path";
 export { isClineAccountFeatureEnabled } from "./services/feature-flags/cline-account-feature-flags";
+export {
+	ComputerUseClient,
+	type ComputerUseClientOptions,
+	type ComputerUseAction,
+	type ComputerUseCoordinate,
+	type ComputerUseDisplayInfo,
+	type ComputerUseImage,
+	type ComputerUseRequest,
+	type ComputerUseResponse,
+	createComputerUseTool,
+	createComputerUseToolFromEnv,
+	GET_DISPLAY_INFO_ACTION,
+	isComputerUseResponse,
+	type ComputerUseToolOptions,
+} from "./extensions/computer-use";
 export {
 	applyClineFeaturedModels,
 	type ClineRecommendedModel,
diff --git a/sdk/packages/llms/src/providers/routing/anthropic-compatible.test.ts b/sdk/packages/llms/src/providers/routing/anthropic-compatible.test.ts
index ea6d1cdb6f..b3e27e3d0d 100644
--- a/sdk/packages/llms/src/providers/routing/anthropic-compatible.test.ts
+++ b/sdk/packages/llms/src/providers/routing/anthropic-compatible.test.ts
@@ -2,6 +2,7 @@ import type {
 	GatewayModelRoute,
 	GatewayProviderContext,
 	GatewayProviderManifest,
+	GatewayStreamRequest,
 } from "@cline/shared";
 import { describe, expect, it } from "vitest";
 import {
@@ -14,6 +15,7 @@ import {
 } from "../model-facts";
 import {
 	applyPromptCacheToLastTextPart,
+	buildAnthropicProviderOptions,
 	resolveAnthropicReasoningRequestPolicy,
 	resolvePromptCacheRoute,
 	shouldApplyPromptCache,
@@ -652,3 +654,51 @@ describe("anthropic-compatible routing helpers", () => {
 		});
 	});
 });
+
+describe("buildAnthropicProviderOptions computer-use beta header", () => {
+	function makeRequest(
+		overrides: Partial<GatewayStreamRequest> = {},
+	): GatewayStreamRequest {
+		return {
+			providerId: "anthropic",
+			modelId: "claude-sonnet-4-6",
+			messages: [],
+			...overrides,
+		};
+	}
+
+	it("sends the computer-use beta header for the direct anthropic wire target", () => {
+		const options = buildAnthropicProviderOptions(
+			makeRequest(),
+			makeContext("anthropic"),
+			"anthropic",
+		);
+
+		expect(options.anthropicBeta).toEqual(["computer-use-2025-11-24"]);
+	});
+
+	it("does not send the beta header for other Anthropic-lineage wire targets", () => {
+		const bedrockOptions = buildAnthropicProviderOptions(
+			makeRequest({ providerId: "bedrock" }),
+			makeContext("anthropic"),
+			"bedrock",
+		);
+		expect(bedrockOptions.anthropicBeta).toBeUndefined();
+
+		const vertexOptions = buildAnthropicProviderOptions(
+			makeRequest({ providerId: "vertex" }),
+			makeContext("anthropic"),
+			"vertex",
+		);
+		expect(vertexOptions.anthropicBeta).toBeUndefined();
+	});
+
+	it("does not send the beta header when target is omitted", () => {
+		const options = buildAnthropicProviderOptions(
+			makeRequest(),
+			makeContext("anthropic"),
+		);
+
+		expect(options.anthropicBeta).toBeUndefined();
+	});
+});
diff --git a/sdk/packages/llms/src/providers/routing/anthropic-compatible.ts b/sdk/packages/llms/src/providers/routing/anthropic-compatible.ts
index 9a09713323..9d2daf9b22 100644
--- a/sdk/packages/llms/src/providers/routing/anthropic-compatible.ts
+++ b/sdk/packages/llms/src/providers/routing/anthropic-compatible.ts
@@ -15,12 +15,26 @@ import {
 	resolveClaudeThinkingEra,
 	resolveModelFamily,
 } from "../model-facts";
+import type { AiSdkProviderOptionsTarget } from "./provider-options-types";
 import {
 	createEphemeralCacheControl,
 	toProviderOptionsBucket,
 	toProviderOptionsKey,
 } from "./utils";
 
+/**
+ * Anthropic beta features gated behind the `anthropic-beta` request header.
+ *
+ * `computer-use-2025-11-24` unlocks the extended computer-use action set
+ * (scroll, wait, zoom, etc.) on the direct Anthropic Messages API. This is
+ * always sent for the direct `anthropic` wire target for now (proof of
+ * concept); it is intentionally NOT sent for other Anthropic-lineage wire
+ * adapters (Bedrock, Vertex, MiniMax, SAP AI Core, ...) since those go
+ * through different request shapes/protocols that don't necessarily accept
+ * this header the same way.
+ */
+const ANTHROPIC_BETA_FEATURES: readonly string[] = ["computer-use-2025-11-24"];
+
 const ANTHROPIC_DEFAULT_THINKING_BUDGET_TOKENS = 1024;
 const ANTHROPIC_MAX_THINKING_BUDGET_TOKENS = 128000;
 
@@ -367,6 +381,7 @@ export function resolveAnthropicReasoningRequestPolicy(
 export function buildAnthropicProviderOptions(
 	request: GatewayStreamRequest,
 	context: GatewayProviderContext,
+	target?: AiSdkProviderOptionsTarget,
 ) {
 	const explicitBudget =
 		request.reasoning?.enabled === false
@@ -399,6 +414,12 @@ export function buildAnthropicProviderOptions(
 		...(shouldApplyAnthropicCacheBucket(request, context)
 			? createEphemeralCacheControl()
 			: {}),
+		// POC: always send the computer-use beta header on the direct
+		// Anthropic wire target. Not gated per-model/per-tool yet; revisit
+		// before this leaves proof-of-concept status.
+		...(target === "anthropic"
+			? { anthropicBeta: [...ANTHROPIC_BETA_FEATURES] }
+			: {}),
 	};
 }
 
diff --git a/sdk/packages/llms/src/providers/routing/provider-options.ts b/sdk/packages/llms/src/providers/routing/provider-options.ts
index 3b655da1aa..24189772a8 100644
--- a/sdk/packages/llms/src/providers/routing/provider-options.ts
+++ b/sdk/packages/llms/src/providers/routing/provider-options.ts
@@ -98,6 +98,7 @@ export function composeAiSdkProviderOptions(
 	const anthropicOptions = buildAnthropicProviderOptions(
 		normalizedRequest,
 		context,
+		target,
 	);
 	const buildInput = {
 		...matchInput,