diff --git a/apis/libmcpcomputer.lua b/apis/libmcpcomputer.lua
new file mode 100644
index 0000000..63ea20a
--- /dev/null
+++ b/apis/libmcpcomputer.lua
@@ -0,0 +1,91 @@
+local function defaultOs()
+  return os;
+end
+
+local function formatLabel(label)
+  if type(label) ~= 'string' or label == '' then
+    return 'null';
+  end
+  return label;
+end
+
+local function createMcpComputer()
+  local api = {};
+
+  api.formatLabel = formatLabel;
+
+  function api.formatPong(osLike)
+    osLike = osLike or defaultOs();
+    return 'pong from ' .. tostring(osLike.getComputerID())
+      .. ' (Label: ' .. formatLabel(osLike.getComputerLabel()) .. ')';
+  end
+
+  function api.parseArgs(args)
+    args = args or {};
+    local count = args.n or #args;
+    local url = nil;
+
+    if count == 0 then
+      return nil, 'missing websocket URL';
+    end
+
+    local i = 1;
+    while i <= count do
+      local arg = args[i];
+      if arg == '-url' then
+        if not args[i + 1] or args[i + 1] == '' then
+          return nil, 'missing value for -url';
+        end
+        url = args[i + 1];
+        i = i + 1;
+      elseif string.sub(tostring(arg), 1, 1) == '-' then
+        return nil, 'unknown option: ' .. tostring(arg);
+      elseif not url then
+        url = arg;
+      else
+        return nil, 'unexpected argument: ' .. tostring(arg);
+      end
+      i = i + 1;
+    end
+
+    if not url or url == '' then
+      return nil, 'missing websocket URL';
+    end
+    return { url = url };
+  end
+
+  function api.hello(osLike)
+    osLike = osLike or defaultOs();
+    return {
+      type = 'hello',
+      computerId = osLike.getComputerID(),
+      computerLabel = osLike.getComputerLabel(),
+    };
+  end
+
+  function api.handleRequest(request, osLike)
+    if type(request) ~= 'table' or request.type ~= 'request' or type(request.id) ~= 'string' then
+      return nil;
+    end
+
+    if request.method == 'ping' then
+      return {
+        type = 'response',
+        id = request.id,
+        ok = true,
+        result = api.formatPong(osLike),
+      };
+    end
+
+    return {
+      type = 'response',
+      id = request.id,
+      ok = false,
+      error = 'unknown method',
+    };
+  end
+
+  return api;
+end
+
+return createMcpComputer;
diff --git a/packages/index.json b/packages/index.json
index 29e5ac8..d7ae329 100644
--- a/packages/index.json
+++ b/packages/index.json
@@ -6,7 +6,7 @@
     "trapos-net": "0.3.0",
     "trapos-ui": "0.2.2",
     "trapos-ai": "0.6.3",
-    "trapos-sandbox": "0.1.0",
+    "trapos-sandbox": "0.1.1",
     "trapos": "0.8.4"
   }
 }
diff --git a/packages/trapos-sandbox/ccpm.json b/packages/trapos-sandbox/ccpm.json
index 076d1c3..90bff76 100644
--- a/packages/trapos-sandbox/ccpm.json
+++ b/packages/trapos-sandbox/ccpm.json
@@ -1,11 +1,13 @@
 {
   "name": "trapos-sandbox",
-  "version": "0.1.0",
+  "version": "0.1.1",
   "description": "TrapOS sandbox programs for ccpm experiments and Lua learning",
   "dependencies": ["trapos-core"],
   "files": [
     "apis/libcarre.lua",
-    "programs/carre.lua"
+    "apis/libmcpcomputer.lua",
+    "programs/carre.lua",
+    "programs/mcp-computer.lua"
   ],
   "autostart": []
 }
diff --git a/programs/mcp-computer.lua b/programs/mcp-computer.lua
new file mode 100644
index 0000000..465a4fd
--- /dev/null
+++ b/programs/mcp-computer.lua
@@ -0,0 +1,113 @@
+local createMcpComputer = require('/apis/libmcpcomputer');
+local createVersion = require('/apis/libversion');
+
+local args = table.pack(...);
+local command = args[1];
+
+local function printUsage()
+  print('mcp-computer usage:');
+  print();
+  print('  mcp-computer <ws-url>');
+  print('  mcp-computer -url <ws-url>');
+  print('  mcp-computer --version');
+  print('  mcp-computer --help');
+  print();
+  print('examples:');
+  print('  mcp-computer ws://192.168.1.20:3001');
+  print('  mcp-computer -url ws://mcp-bridge.local:3001');
+end
+
+local function fail(message)
+  print(message);
+  error('mcp-computer failed', 0);
+end
+
+local function decodeJson(text)
+  return textutils.unserializeJSON(text);
+end
+
+local function sendJson(ws, value)
+  ws.send(textutils.serializeJSON(value));
+end
+
+local function waitForHelloOk(ws)
+  local message = ws.receive(5);
+  if not message then
+    return false, 'timed out waiting for hello-ok';
+  end
+
+  local frame = decodeJson(message);
+  if type(frame) ~= 'table' or frame.type ~= 'hello-ok' then
+    return false, 'unexpected hello response';
+  end
+
+  return true;
+end
+
+if command == '-help' or command == '--help' or command == 'help' then
+  printUsage();
+  return;
+end
+
+if command == '-version' or command == '--version' or command == 'version' then
+  print('v' .. createVersion().forSelf());
+  return;
+end
+
+local mcpComputer = createMcpComputer();
+local config, err = mcpComputer.parseArgs(args);
+if not config then
+  print(err);
+  print('use: mcp-computer -help');
+  return;
+end
+
+if not http then
+  fail('CC:Tweaked HTTP/WebSocket is unavailable: enable the http API.');
+end
+
+if not http.websocket then
+  fail('CC:Tweaked WebSocket is unavailable: enable HTTP WebSocket support.');
+end
+
+local version = createVersion().forSelf();
+print('mcp-computer v' .. version .. ' connecting to ' .. config.url);
+
+local ws, connectErr = http.websocket(config.url);
+if not ws then
+  fail('websocket failed: ' .. tostring(connectErr));
+end
+
+local ok, runtimeErr = pcall(function()
+  sendJson(ws, mcpComputer.hello(os));
+
+  local helloOk, helloErr = waitForHelloOk(ws);
+  if not helloOk then
+    error(helloErr, 0);
+  end
+
+  print('linked as ' .. tostring(os.getComputerID())
+    .. ' (Label: ' .. mcpComputer.formatLabel(os.getComputerLabel()) .. ')');
+  print('waiting for requests... Press Ctrl+T to stop.');
+
+  while true do
+    local message = ws.receive();
+    if not message then return; end
+
+    local frame = decodeJson(message);
+    local response = mcpComputer.handleRequest(frame, os);
+    if response then
+      sendJson(ws, response);
+    end
+  end
+end);
+
+pcall(function() ws.close(); end);
+
+if not ok then
+  if tostring(runtimeErr) == 'Terminated' then
+    print('stopped.');
+    return;
+  end
+  fail(tostring(runtimeErr));
+end
diff --git a/tests/mcpcomputer.lua b/tests/mcpcomputer.lua
new file mode 100644
index 0000000..c5330b4
--- /dev/null
+++ b/tests/mcpcomputer.lua
@@ -0,0 +1,96 @@
+local createLibTest = require('/apis/libtest');
+local createMcpComputer = require('/apis/libmcpcomputer');
+
+local testlib = createLibTest({ ... });
+
+local function packed(...)
+  return table.pack(...);
+end
+
+local function fakeOs(id, label)
+  return {
+    getComputerID = function() return id; end,
+    getComputerLabel = function() return label; end,
+  };
+end
+
+testlib.test('parseArgs accepts positional URL', function()
+  local mcpComputer = createMcpComputer();
+  local config = mcpComputer.parseArgs(packed('ws://127.0.0.1:3001'));
+
+  testlib.assertEquals(config.url, 'ws://127.0.0.1:3001');
+end);
+
+testlib.test('parseArgs accepts -url option', function()
+  local mcpComputer = createMcpComputer();
+  local config = mcpComputer.parseArgs(packed('-url', 'ws://bridge:3001'));
+
+  testlib.assertEquals(config.url, 'ws://bridge:3001');
+end);
+
+testlib.test('parseArgs rejects missing URL', function()
+  local mcpComputer = createMcpComputer();
+  local config, err = mcpComputer.parseArgs(packed());
+
+  testlib.assertEquals(config, nil);
+  testlib.assertTrue(string.find(err, 'missing websocket URL', 1, true));
+end);
+
+testlib.test('formatPong includes computer id and label', function()
+  local mcpComputer = createMcpComputer();
+
+  testlib.assertEquals(mcpComputer.formatPong(fakeOs(12, 'base-turtle')), 'pong from 12 (Label: base-turtle)');
+end);
+
+testlib.test('formatPong renders missing or empty labels as null', function()
+  local mcpComputer = createMcpComputer();
+
+  testlib.assertEquals(mcpComputer.formatPong(fakeOs(7, nil)), 'pong from 7 (Label: null)');
+  testlib.assertEquals(mcpComputer.formatPong(fakeOs(8, '')), 'pong from 8 (Label: null)');
+end);
+
+testlib.test('hello identifies the current computer', function()
+  local mcpComputer = createMcpComputer();
+  local hello = mcpComputer.hello(fakeOs(3, 'agent'));
+
+  testlib.assertEquals(hello.type, 'hello');
+  testlib.assertEquals(hello.computerId, 3);
+  testlib.assertEquals(hello.computerLabel, 'agent');
+end);
+
+testlib.test('handleRequest responds to ping', function()
+  local mcpComputer = createMcpComputer();
+  local response = mcpComputer.handleRequest({
+    type = 'request',
+    id = 'req-1',
+    method = 'ping',
+  }, fakeOs(42, 'worker'));
+
+  testlib.assertEquals(response.type, 'response');
+  testlib.assertEquals(response.id, 'req-1');
+  testlib.assertEquals(response.ok, true);
+  testlib.assertEquals(response.result, 'pong from 42 (Label: worker)');
+end);
+
+testlib.test('handleRequest reports unknown methods', function()
+  local mcpComputer = createMcpComputer();
+  local response = mcpComputer.handleRequest({
+    type = 'request',
+    id = 'req-2',
+    method = 'dance',
+  }, fakeOs(42, 'worker'));
+
+  testlib.assertEquals(response.type, 'response');
+  testlib.assertEquals(response.id, 'req-2');
+  testlib.assertEquals(response.ok, false);
+  testlib.assertEquals(response.error, 'unknown method');
+end);
+
+testlib.test('handleRequest ignores malformed frames', function()
+  local mcpComputer = createMcpComputer();
+
+  testlib.assertEquals(mcpComputer.handleRequest({ type = 'request', method = 'ping' }, fakeOs(1, nil)), nil);
+  testlib.assertEquals(mcpComputer.handleRequest({ type = 'hello' }, fakeOs(1, nil)), nil);
+end);
+
+testlib.run();
diff --git a/tools/mcp-bridge/test-integration/harness.ts b/tools/mcp-bridge/test-integration/harness.ts
index 9657270..d9b6da8 100644
--- a/tools/mcp-bridge/test-integration/harness.ts
+++ b/tools/mcp-bridge/test-integration/harness.ts
@@ -10,6 +10,7 @@ import { startMcpServer } from "../src/mcp-server.js";
 
 const HERE = dirname(fileURLToPath(import.meta.url));
 const LUA_DIR = join(HERE, "lua");
+const REPO_ROOT = join(HERE, "../../..");
 
 export const MCP_PORT = 2000;
 export const LINK_PORT = 2001;
@@ -77,7 +78,7 @@ export type CraftosHandle = {
 
 export function startCraftos(
   luaName: string,
-  opts: { shellArgs?: string[]; timeoutMs?: number } = {},
+  opts: { mountRepo?: boolean; shellArgs?: string[]; timeoutMs?: number } = {},
 ): CraftosHandle {
   const timeoutMs = opts.timeoutMs ?? 15_000;
   const controller = new AbortController();
@@ -87,6 +88,13 @@ export function startCraftos(
     const watchdog = setTimeout(() => controller.abort(), timeoutMs);
     try {
       const args: string[] = ["--directory", dataDir, "--headless", "--mount-ro", `/staging=${LUA_DIR}`];
+      if (opts.mountRepo) {
+        args.push(
+          "--mount-ro", `/trapos=${REPO_ROOT}`,
+          "--mount-ro", `/apis=${join(REPO_ROOT, "apis")}`,
+          "--mount-ro", `/programs=${join(REPO_ROOT, "programs")}`,
+        );
+      }
       if (process.platform === "darwin") {
         args.push("--rom", "/Applications/CraftOS-PC.app/Contents/Resources");
       }
@@ -118,7 +126,8 @@ export function formatFailure(message: string, craftosOutput: string): string {
 }
 
 function buildExecCode(luaName: string, shellArgs: string[]): string {
-  const parts = [`'/staging/${luaName}'`, ...shellArgs.map(luaQuote)];
+  const programPath = luaName.startsWith("/") ? luaName : `/staging/${luaName}`;
+  const parts = [luaQuote(programPath), ...shellArgs.map(luaQuote)];
   return `shell.run(${parts.join(", ")})`;
 }
 
diff --git a/tools/mcp-bridge/test-integration/probe-real-program.test.ts b/tools/mcp-bridge/test-integration/probe-real-program.test.ts
new file mode 100644
index 0000000..1175e2f
--- /dev/null
+++ b/tools/mcp-bridge/test-integration/probe-real-program.test.ts
@@ -0,0 +1,25 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+import { callProbeComputers, formatFailure, startBridge, startCraftos, waitForComputers } from "./harness.js";
+
+test("probe-computers talks to the real TrapOS mcp-computer program", async () => {
+  const bridge = await startBridge();
+  const craftos = startCraftos("/programs/mcp-computer.lua", {
+    mountRepo: true,
+    shellArgs: ["ws://127.0.0.1:2001"],
+    timeoutMs: 15_000,
+  });
+  try {
+    await waitForComputers(bridge.registry, 1, 12_000);
+    const text = await callProbeComputers();
+    assert.equal(text, "pong from 0 (Label: null)");
+  } catch (error) {
+    craftos.abort();
+    const result = await craftos.done;
+    throw new Error(formatFailure(error instanceof Error ? error.message : String(error), result.output), { cause: error });
+  } finally {
+    craftos.abort();
+    await craftos.done;
+    await bridge.close();
+  }
+});