feat: add McpScreen phase 2 display tools

Apps/AudioTest/CMakeLists.txt

@@ -0,0 +1,16 @@
+cmake_minimum_required(VERSION 3.20)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+
+if (DEFINED ENV{TACTILITY_SDK_PATH})
+    set(TACTILITY_SDK_PATH $ENV{TACTILITY_SDK_PATH})
+else()
+    set(TACTILITY_SDK_PATH "../../release/TactilitySDK")
+    message(WARNING "⚠️ TACTILITY_SDK_PATH environment variable is not set, defaulting to ${TACTILITY_SDK_PATH}")
+endif()
+
+include("${TACTILITY_SDK_PATH}/TactilitySDK.cmake")
+set(EXTRA_COMPONENT_DIRS ${TACTILITY_SDK_PATH})
+
+project(AudioTest)
+tactility_project(AudioTest)

Apps/AudioTest/main/CMakeLists.txt

@@ -0,0 +1,6 @@
+file(GLOB_RECURSE SOURCE_FILES Source/*.c)
+
+idf_component_register(
+    SRCS ${SOURCE_FILES}
+    REQUIRES TactilitySDK
+)

Apps/AudioTest/main/Source/main.c

@@ -0,0 +1,337 @@
+/**
+ * Audio Test - Record & Playback
+ *
+ * Records from the ES8311 microphone via I2S and plays it back through
+ * the FM8002E speaker amplifier. Uses the Tactility kernel I2S controller API.
+ *
+ * UI: Two buttons - Record and Play
+ *   Record: holds recording for up to ~3 seconds (16kHz 16-bit mono ≈ 96KB)
+ *   Play:   plays back the last recorded buffer
+ */
+
+#include <tt_app.h>
+#include <tt_lvgl.h>
+#include <tt_lvgl_toolbar.h>
+
+#include <tactility/device.h>
+#include <tactility/drivers/i2s_controller.h>
+
+#include <string.h>
+#include <stdlib.h>
+
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "esp_log.h"
+
+#define TAG "AudioTest"
+
+/* ─── Audio params ─── */
+#define SAMPLE_RATE      16000
+#define BITS_PER_SAMPLE  16
+#define RECORD_SECONDS   3
+
+/* 16-bit mono → 2 bytes per sample */
+#define AUDIO_BUF_SIZE   (SAMPLE_RATE * (BITS_PER_SAMPLE / 8) * RECORD_SECONDS)
+
+/* Chunk size for read/write calls (512 samples = 1024 bytes at 16-bit) */
+#define CHUNK_SAMPLES    512
+#define CHUNK_BYTES      (CHUNK_SAMPLES * (BITS_PER_SAMPLE / 8))
+
+/* ─── App state ─── */
+typedef enum {
+    STATE_IDLE,
+    STATE_RECORDING,
+    STATE_PLAYING
+} AudioState;
+
+typedef struct {
+    struct Device* i2s_dev;
+    uint8_t*       audio_buf;
+    size_t         recorded_bytes;
+    AudioState     state;
+    lv_obj_t*      btn_record;
+    lv_obj_t*      btn_play;
+    lv_obj_t*      lbl_status;
+    lv_obj_t*      bar_progress;
+    TaskHandle_t   task_handle;
+} AppCtx;
+
+/* ─── Forward decls ─── */
+static void record_task(void* arg);
+static void play_task(void* arg);
+static void update_ui(AppCtx* ctx);
+
+/* ─── Callbacks ─── */
+static void on_record_click(lv_event_t* e) {
+    AppCtx* ctx = (AppCtx*)lv_event_get_user_data(e);
+    if (ctx->state != STATE_IDLE) return;
+    if (ctx->i2s_dev == NULL) return;
+
+    ctx->state = STATE_RECORDING;
+    ctx->recorded_bytes = 0;
+    update_ui(ctx);
+
+    xTaskCreate(record_task, "audio_rec", 4096, ctx, 5, &ctx->task_handle);
+}
+
+static void on_play_click(lv_event_t* e) {
+    AppCtx* ctx = (AppCtx*)lv_event_get_user_data(e);
+    if (ctx->state != STATE_IDLE) return;
+    if (ctx->recorded_bytes == 0) return;
+    if (ctx->i2s_dev == NULL) return;
+
+    ctx->state = STATE_PLAYING;
+    update_ui(ctx);
+
+    xTaskCreate(play_task, "audio_play", 4096, ctx, 5, &ctx->task_handle);
+}
+
+/* ─── Update UI labels/buttons from any context ─── */
+static void update_ui(AppCtx* ctx) {
+    if (ctx->lbl_status == NULL) return;
+
+    switch (ctx->state) {
+        case STATE_RECORDING:
+            lv_label_set_text(ctx->lbl_status, "🔴 Recording...");
+            lv_obj_add_state(ctx->btn_record, LV_STATE_DISABLED);
+            lv_obj_add_state(ctx->btn_play, LV_STATE_DISABLED);
+            break;
+        case STATE_PLAYING:
+            lv_label_set_text(ctx->lbl_status, "🔊 Playing...");
+            lv_obj_add_state(ctx->btn_record, LV_STATE_DISABLED);
+            lv_obj_add_state(ctx->btn_play, LV_STATE_DISABLED);
+            break;
+        case STATE_IDLE:
+        default:
+            if (ctx->recorded_bytes > 0) {
+                char buf[64];
+                snprintf(buf, sizeof(buf), "Ready (%u bytes recorded)", (unsigned)ctx->recorded_bytes);
+                lv_label_set_text(ctx->lbl_status, buf);
+            } else {
+                lv_label_set_text(ctx->lbl_status, "Press Record to capture audio");
+            }
+            lv_obj_clear_state(ctx->btn_record, LV_STATE_DISABLED);
+            if (ctx->recorded_bytes > 0) {
+                lv_obj_clear_state(ctx->btn_play, LV_STATE_DISABLED);
+            } else {
+                lv_obj_add_state(ctx->btn_play, LV_STATE_DISABLED);
+            }
+            break;
+    }
+}
+
+/* ─── Record task ─── */
+static void record_task(void* arg) {
+    AppCtx* ctx = (AppCtx*)arg;
+    size_t total = 0;
+    size_t bytes_read = 0;
+
+    /* Configure I2S for recording */
+    struct I2sConfig cfg = {
+        .communication_format = I2S_FORMAT_STAND_I2S,
+        .sample_rate = SAMPLE_RATE,
+        .bits_per_sample = BITS_PER_SAMPLE,
+        .channel_left = 0,
+        .channel_right = I2S_CHANNEL_NONE
+    };
+
+    device_lock(ctx->i2s_dev);
+    error_t err = i2s_controller_set_config(ctx->i2s_dev, &cfg);
+    device_unlock(ctx->i2s_dev);
+
+    if (err != ERROR_NONE) {
+        ESP_LOGE(TAG, "Failed to set I2S config for recording: %d", err);
+        tt_lvgl_lock(portMAX_DELAY);
+        ctx->state = STATE_IDLE;
+        update_ui(ctx);
+        tt_lvgl_unlock();
+        vTaskDelete(NULL);
+        return;
+    }
+
+    ESP_LOGI(TAG, "Recording started (max %d bytes)", AUDIO_BUF_SIZE);
+
+    while (total < AUDIO_BUF_SIZE && ctx->state == STATE_RECORDING) {
+        size_t remaining = AUDIO_BUF_SIZE - total;
+        size_t to_read = (remaining < CHUNK_BYTES) ? remaining : CHUNK_BYTES;
+
+        err = i2s_controller_read(ctx->i2s_dev,
+                                  ctx->audio_buf + total,
+                                  to_read,
+                                  &bytes_read,
+                                  pdMS_TO_TICKS(1000));
+        if (err != ERROR_NONE) {
+            ESP_LOGE(TAG, "I2S read error: %d", err);
+            break;
+        }
+        total += bytes_read;
+
+        /* Update progress bar */
+        int pct = (int)((total * 100) / AUDIO_BUF_SIZE);
+        tt_lvgl_lock(portMAX_DELAY);
+        lv_bar_set_value(ctx->bar_progress, pct, LV_ANIM_OFF);
+        tt_lvgl_unlock();
+    }
+
+    ctx->recorded_bytes = total;
+    ctx->state = STATE_IDLE;
+    ctx->task_handle = NULL;
+
+    ESP_LOGI(TAG, "Recording complete: %u bytes", (unsigned)total);
+
+    tt_lvgl_lock(portMAX_DELAY);
+    lv_bar_set_value(ctx->bar_progress, 0, LV_ANIM_OFF);
+    update_ui(ctx);
+    tt_lvgl_unlock();
+    vTaskDelete(NULL);
+}
+
+/* ─── Play task ─── */
+static void play_task(void* arg) {
+    AppCtx* ctx = (AppCtx*)arg;
+    size_t total = 0;
+    size_t bytes_written = 0;
+
+    /* Configure I2S for playback */
+    struct I2sConfig cfg = {
+        .communication_format = I2S_FORMAT_STAND_I2S,
+        .sample_rate = SAMPLE_RATE,
+        .bits_per_sample = BITS_PER_SAMPLE,
+        .channel_left = 0,
+        .channel_right = I2S_CHANNEL_NONE
+    };
+
+    device_lock(ctx->i2s_dev);
+    error_t err = i2s_controller_set_config(ctx->i2s_dev, &cfg);
+    device_unlock(ctx->i2s_dev);
+
+    if (err != ERROR_NONE) {
+        ESP_LOGE(TAG, "Failed to set I2S config for playback: %d", err);
+        tt_lvgl_lock(portMAX_DELAY);
+        ctx->state = STATE_IDLE;
+        update_ui(ctx);
+        tt_lvgl_unlock();
+        vTaskDelete(NULL);
+        return;
+    }
+
+    ESP_LOGI(TAG, "Playback started (%u bytes)", (unsigned)ctx->recorded_bytes);
+
+    while (total < ctx->recorded_bytes && ctx->state == STATE_PLAYING) {
+        size_t remaining = ctx->recorded_bytes - total;
+        size_t to_write = (remaining < CHUNK_BYTES) ? remaining : CHUNK_BYTES;
+
+        err = i2s_controller_write(ctx->i2s_dev,
+                                   ctx->audio_buf + total,
+                                   to_write,
+                                   &bytes_written,
+                                   pdMS_TO_TICKS(1000));
+        if (err != ERROR_NONE) {
+            ESP_LOGE(TAG, "I2S write error: %d", err);
+            break;
+        }
+        total += bytes_written;
+
+        /* Update progress bar */
+        int pct = (int)((total * 100) / ctx->recorded_bytes);
+        tt_lvgl_lock(portMAX_DELAY);
+        lv_bar_set_value(ctx->bar_progress, pct, LV_ANIM_OFF);
+        tt_lvgl_unlock();
+    }
+
+    ctx->state = STATE_IDLE;
+    ctx->task_handle = NULL;
+
+    ESP_LOGI(TAG, "Playback complete");
+
+    tt_lvgl_lock(portMAX_DELAY);
+    lv_bar_set_value(ctx->bar_progress, 0, LV_ANIM_OFF);
+    update_ui(ctx);
+    tt_lvgl_unlock();
+    vTaskDelete(NULL);
+}
+
+/* ─── App lifecycle ─── */
+static AppCtx g_ctx;
+
+static void onShowApp(AppHandle app, void* data, lv_obj_t* parent) {
+    memset(&g_ctx, 0, sizeof(g_ctx));
+
+    /* Allocate audio buffer */
+    g_ctx.audio_buf = (uint8_t*)malloc(AUDIO_BUF_SIZE);
+    if (g_ctx.audio_buf == NULL) {
+        ESP_LOGE(TAG, "Failed to allocate audio buffer (%d bytes)", AUDIO_BUF_SIZE);
+    }
+
+    /* Find I2S device */
+    g_ctx.i2s_dev = device_find_by_name("i2s0");
+    if (g_ctx.i2s_dev == NULL) {
+        ESP_LOGE(TAG, "I2S device 'i2s0' not found!");
+    } else {
+        ESP_LOGI(TAG, "Found I2S device: %s", g_ctx.i2s_dev->name);
+    }
+
+    /* ─── UI ─── */
+    lv_obj_t* toolbar = tt_lvgl_toolbar_create_for_app(parent, app);
+    lv_obj_align(toolbar, LV_ALIGN_TOP_MID, 0, 0);
+
+    /* Status label */
+    g_ctx.lbl_status = lv_label_create(parent);
+    lv_label_set_text(g_ctx.lbl_status, "Initializing...");
+    lv_obj_set_width(g_ctx.lbl_status, lv_pct(90));
+    lv_label_set_long_mode(g_ctx.lbl_status, LV_LABEL_LONG_WRAP);
+    lv_obj_set_style_text_align(g_ctx.lbl_status, LV_TEXT_ALIGN_CENTER, 0);
+    lv_obj_align(g_ctx.lbl_status, LV_ALIGN_TOP_MID, 0, 50);
+
+    /* Progress bar */
+    g_ctx.bar_progress = lv_bar_create(parent);
+    lv_obj_set_size(g_ctx.bar_progress, lv_pct(80), 10);
+    lv_bar_set_range(g_ctx.bar_progress, 0, 100);
+    lv_bar_set_value(g_ctx.bar_progress, 0, LV_ANIM_OFF);
+    lv_obj_align(g_ctx.bar_progress, LV_ALIGN_CENTER, 0, -10);
+
+    /* Button container */
+    lv_obj_t* btn_container = lv_obj_create(parent);
+    lv_obj_remove_style_all(btn_container);
+    lv_obj_set_size(btn_container, lv_pct(90), 50);
+    lv_obj_set_flex_flow(btn_container, LV_FLEX_FLOW_ROW);
+    lv_obj_set_flex_align(btn_container, LV_FLEX_ALIGN_SPACE_EVENLY, LV_FLEX_ALIGN_CENTER, LV_FLEX_ALIGN_CENTER);
+    lv_obj_align(btn_container, LV_ALIGN_CENTER, 0, 30);
+
+    /* Record button */
+    g_ctx.btn_record = lv_btn_create(btn_container);
+    lv_obj_set_size(g_ctx.btn_record, 100, 40);
+    lv_obj_t* lbl_rec = lv_label_create(g_ctx.btn_record);
+    lv_label_set_text(lbl_rec, LV_SYMBOL_AUDIO " Record");
+    lv_obj_center(lbl_rec);
+    lv_obj_add_event_cb(g_ctx.btn_record, on_record_click, LV_EVENT_CLICKED, &g_ctx);
+
+    /* Play button */
+    g_ctx.btn_play = lv_btn_create(btn_container);
+    lv_obj_set_size(g_ctx.btn_play, 100, 40);
+    lv_obj_t* lbl_play = lv_label_create(g_ctx.btn_play);
+    lv_label_set_text(lbl_play, LV_SYMBOL_PLAY " Play");
+    lv_obj_center(lbl_play);
+    lv_obj_add_event_cb(g_ctx.btn_play, on_play_click, LV_EVENT_CLICKED, &g_ctx);
+
+    /* Check initialization status */
+    if (g_ctx.i2s_dev == NULL) {
+        lv_label_set_text(g_ctx.lbl_status, "ERROR: I2S device not found");
+        lv_obj_add_state(g_ctx.btn_record, LV_STATE_DISABLED);
+        lv_obj_add_state(g_ctx.btn_play, LV_STATE_DISABLED);
+    } else if (g_ctx.audio_buf == NULL) {
+        lv_label_set_text(g_ctx.lbl_status, "ERROR: Out of memory");
+        lv_obj_add_state(g_ctx.btn_record, LV_STATE_DISABLED);
+        lv_obj_add_state(g_ctx.btn_play, LV_STATE_DISABLED);
+    } else {
+        g_ctx.state = STATE_IDLE;
+        update_ui(&g_ctx);
+    }
+}
+
+int main(int argc, char* argv[]) {
+    tt_app_register((AppRegistration) {
+        .onShow = onShowApp
+    });
+    return 0;
+}

Apps/AudioTest/manifest.properties

@@ -0,0 +1,10 @@
+[manifest]
+version=0.1
+[target]
+sdk=0.7.0-dev
+platforms=esp32s3
+[app]
+id=one.tactility.audiotest
+versionName=0.1.0
+versionCode=1
+name=Audio Test

Apps/HelloWorld/main/Source/main.c

@@ -1,6 +1,23 @@
 #include <tt_app.h>
 #include <tt_lvgl_toolbar.h>
 
+#define TICK_MS 25
+lv_timer_t* gameTimer;
+
+static void onTick(lv_timer_t* timer) {
+    // 1. Retrieve the progress bar using the official getter function
+    lv_obj_t* bar_progress = (lv_obj_t*) lv_timer_get_user_data(timer);
+    int32_t current_val = lv_bar_get_value(bar_progress);
+    
+
+    // 4. Stop and delete the timer when it reaches 100
+    if (current_val + 1 >= 100) {
+        lv_bar_set_value(bar_progress, 0, LV_ANIM_ON);
+    } else {
+        lv_bar_set_value(bar_progress, current_val + 1, LV_ANIM_OFF);
+    }
+}
+
 /**
  * Note: LVGL and Tactility methods need to be exposed manually from TactilityC/Source/tt_init.cpp
  * Only C is supported for now (C++ symbols fail to link)
@@ -10,13 +27,37 @@ static void onShowApp(AppHandle app, void* data, lv_obj_t* parent) {
     lv_obj_align(toolbar, LV_ALIGN_TOP_MID, 0, 0);
 
     lv_obj_t* label = lv_label_create(parent);
-    lv_label_set_text(label, "Hello, world!\n(Loaded via LAN!)");
+    lv_label_set_text(label, "Hello, world!\n(Adolfo Made It2!)");
     lv_obj_align(label, LV_ALIGN_CENTER, 0, 0);
+
+    lv_obj_t* label2 = lv_label_create(parent);
+    lv_label_set_text(label2, "Hello, There!");
+    lv_obj_align(label2, LV_ALIGN_BOTTOM_MID, 0, 0);
+
+     /* Progress bar */
+    lv_obj_t* bar_progress = lv_bar_create(parent);
+    lv_obj_set_size(bar_progress, lv_pct(80), 10);
+    lv_bar_set_range(bar_progress, 0, 100);
+    lv_bar_set_value(bar_progress, 50, LV_ANIM_ON);
+    lv_obj_align(bar_progress, LV_ALIGN_CENTER, 0, -30);
+
+    // Start game timer wiht the progress bar as user data 
+    gameTimer = lv_timer_create(onTick, TICK_MS, bar_progress);
+}
+
+//on hide
+static void onHideApp(AppHandle app, void* data) {
+    if (gameTimer) {
+        lv_timer_delete(gameTimer);
+        gameTimer = NULL;
+    }
 }
 
 int main(int argc, char* argv[]) {
     tt_app_register((AppRegistration) {
-        .onShow = onShowApp
+        .onShow = onShowApp,
+        .onHide = onHideApp,
+
     });
     return 0;
 }

Apps/McpScreen/CMakeLists.txt

@@ -0,0 +1,16 @@
+cmake_minimum_required(VERSION 3.20)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+
+if (DEFINED ENV{TACTILITY_SDK_PATH})
+    set(TACTILITY_SDK_PATH $ENV{TACTILITY_SDK_PATH})
+else()
+    set(TACTILITY_SDK_PATH "../../release/TactilitySDK")
+    message(WARNING "TACTILITY_SDK_PATH is not set, defaulting to ${TACTILITY_SDK_PATH}")
+endif()
+
+include("${TACTILITY_SDK_PATH}/TactilitySDK.cmake")
+set(EXTRA_COMPONENT_DIRS ${TACTILITY_SDK_PATH})
+
+project(McpScreen)
+tactility_project(McpScreen)

Apps/McpScreen/IMPLEMENTATION_PLAN.md

@@ -0,0 +1,428 @@
+# McpScreen for Tactility — Implementation Plan
+
+## Goal
+
+Port the hardware-agnostic MCP Screen design from:
+
+`/Users/adolforeyna/Projects/MicroPython/test1/Screen`
+
+into a native Tactility application while preserving compatibility with the
+existing host-side MCP bridge and Hermes voice service.
+
+The original reference documents and implementations are:
+
+- `system_design_specs.md`
+- `mcp_server.py`
+- `mcp_bridge.py`
+- `main.py`
+- `video_stream.py`
+- `voice_assistant.py`
+- `lib/audio_util.py`
+
+## Target application
+
+- Source folder: `Apps/McpScreen`
+- App ID: `one.tactility.mcpscreen`
+- Initial platform: ESP32-S3
+- Initial Tactility SDK: `0.7.0-dev`
+- Language: C/C++ with ESP-IDF, FreeRTOS, Tactility SDK, and LVGL
+
+## Current implementation status
+
+Phase 1 is implemented, builds successfully for ESP32-S3, and has been tested
+on a 320x240 Tactility device at runtime.
+
+Completed:
+
+- Tactility app lifecycle and app-owned drawing area
+- HTTP JSON-RPC endpoint on port 80
+- `tools/list`
+- `get_capabilities`
+- `clear_screen`
+- `draw_text`
+- request-size limits and JSON-RPC error responses
+- live `tools/list` and `get_capabilities` calls
+- live `clear_screen` and `draw_text` calls
+- live malformed-JSON error handling
+- crash-safe HTTP worker shutdown during app destruction
+- three forced stop/start cycles with the management and MCP endpoints still
+  responsive afterward
+
+Blocked by the current external-app ABI:
+
+- UDP discovery requires `lwip_recvfrom` and `lwip_sendto`, which the running
+  Tactility 0.7.0-dev firmware does not export to ELF apps. The existing bridge
+  falls back to HTTP subnet scanning, so MCP connectivity remains available.
+
+Pending verification:
+
+- verify service behavior while the app is genuinely hidden behind another
+  running application. A remote HelloWorld launch did not trigger `onHide`, so
+  this needs a manual launcher/device interaction test.
+
+### Shutdown implementation note
+
+Tactility unloads external-app ELF memory immediately after `onDestroy`
+returns. An app task blocked in `accept()` therefore cannot be allowed to
+survive destruction. The HTTP listener is non-blocking and client reads have
+short timeouts. `onHide` only clears the run flag and returns immediately so
+it does not block Tactility's GUI lifecycle or close an lwIP descriptor from
+the wrong task. The worker owns the socket shutdown, then suspends itself
+asynchronously. The next `onShow` reaps it before starting a new worker, while
+`onDestroy` waits for and deletes it before returning.
+
+## Design principles
+
+1. Preserve the existing MCP tool names and JSON-RPC contract wherever the
+   underlying Tactility hardware supports them.
+2. Keep network, audio, and long-running work outside the LVGL task.
+3. Perform all LVGL operations under the Tactility LVGL lock or dispatch them
+   onto the LVGL task.
+4. Use Tactility device and HAL interfaces instead of board-specific GPIO
+   assumptions wherever possible.
+5. Return structured unsupported-capability errors instead of silently
+   emulating unavailable hardware.
+6. Treat files supplied over MCP as untrusted input and constrain file access
+   to the application's user-data directory.
+7. Do not port `execute_python` literally. Native firmware must not expose
+   arbitrary code execution.
+
+## Proposed application structure
+
+```text
+Apps/McpScreen/
+├── CMakeLists.txt
+├── manifest.properties
+├── IMPLEMENTATION_PLAN.md
+└── main/
+    ├── CMakeLists.txt
+    └── Source/
+        ├── main.cpp
+        ├── McpScreenApp.cpp
+        ├── McpScreenApp.h
+        ├── McpServer.cpp
+        ├── McpServer.h
+        ├── DiscoveryService.cpp
+        ├── DiscoveryService.h
+        ├── ToolRegistry.cpp
+        ├── ToolRegistry.h
+        ├── ToolDispatcher.cpp
+        ├── ToolDispatcher.h
+        ├── DisplayTools.cpp
+        ├── DisplayTools.h
+        ├── AudioTools.cpp
+        ├── AudioTools.h
+        ├── SystemTools.cpp
+        ├── SystemTools.h
+        ├── DashboardView.cpp
+        └── DashboardView.h
+```
+
+The file boundaries may be consolidated during the first slice if a smaller
+implementation is easier to validate.
+
+## Runtime architecture
+
+### Application lifecycle
+
+- `onCreate`
+  - Allocate application state.
+- `onShow`
+  - Build the dashboard and MCP-controlled display canvas.
+  - Attach the current UI objects to the shared application state.
+  - Start the HTTP MCP service.
+- `onHide`
+  - Signal the HTTP MCP service to stop without blocking the GUI lifecycle.
+  - Detach and invalidate UI object pointers.
+- `onDestroy`
+  - Join/delete any remaining worker and close sockets as a safety fallback.
+  - Release buffers, devices, and application state.
+
+The MCP server is deliberately foreground-only. Tactility does not need to
+keep the listener or display-control task active while another app owns the
+screen.
+
+### FreeRTOS responsibilities
+
+- MCP HTTP task
+  - Listen for HTTP requests.
+  - Parse JSON-RPC requests.
+  - Dispatch tools.
+  - Serialize JSON-RPC responses.
+- UDP discovery task
+  - Bind UDP port 5000.
+  - Reply to discovery packets.
+- Display work
+  - Marshal changes through the LVGL lock or an LVGL async callback.
+- Audio tasks
+  - Record and play I2S data without blocking the UI or MCP listener.
+- Future streaming tasks
+  - Own TCP/UDP frame sockets and preallocated frame buffers.
+
+## Network compatibility
+
+### UDP discovery
+
+- Port: `5000`
+- Request: exact bytes `DISCOVER_SCREEN`
+- Response: exact bytes `SCREEN_IP_80`
+
+### MCP HTTP endpoint
+
+- Port: `80`
+- Method and path: `POST /api/mcp`
+- Content type: `application/json`
+- Protocol: JSON-RPC 2.0
+- Required methods:
+  - `tools/list`
+  - `tools/call`
+
+### Raw display endpoint
+
+Added after the basic MCP slice:
+
+- Method and path: `POST /api/screen/raw`
+- Query parameters: `x`, `y`, `w`, `h`
+- Body: raw big-endian RGB565 bytes
+
+## MCP response behavior
+
+Successful tool calls retain the existing shape:
+
+```json
+{
+  "jsonrpc": "2.0",
+  "result": {
+    "content": [
+      {
+        "type": "text",
+        "text": "..."
+      }
+    ]
+  },
+  "id": 1
+}
+```
+
+Errors use JSON-RPC error objects:
+
+```json
+{
+  "jsonrpc": "2.0",
+  "error": {
+    "code": -32000,
+    "message": "..."
+  },
+  "id": 1
+}
+```
+
+## Phase 1 — MCP foundation
+
+### Scope
+
+1. Scaffold `Apps/McpScreen`.
+2. Add a status/dashboard view showing:
+   - Wi-Fi state
+   - server state
+   - port
+   - last tool
+   - last error
+3. Start the HTTP server on port 80.
+4. Implement `POST /api/mcp`.
+5. Implement JSON-RPC request validation and error handling.
+6. Implement `tools/list`.
+7. Implement UDP discovery on port 5000.
+8. Implement the first three tools:
+   - `get_capabilities`
+   - `clear_screen`
+   - `draw_text`
+9. Test with the existing `mcp_bridge.py`.
+
+### Initial tool semantics
+
+#### `get_capabilities`
+
+Return live display information:
+
+```json
+{
+  "color": true,
+  "width": 320,
+  "height": 240,
+  "formats": ["rgb565_base64", "bmp_base64"],
+  "platform": "tactility",
+  "appVersion": "0.1.0"
+}
+```
+
+Width, height, and color format must be queried at runtime.
+
+#### `clear_screen`
+
+- Accept `color` values compatible with the original API:
+  - `0`: white
+  - `1`: black
+- Mark MCP display override active.
+- Clear the app-owned canvas/display area.
+
+#### `draw_text`
+
+- Accept `text`, `x`, `y`, and optional `size`.
+- Mark MCP display override active.
+- Render inside the app-owned canvas.
+- Clamp coordinates to the drawable area.
+
+### Phase 1 acceptance criteria
+
+- The app builds and packages for ESP32-S3.
+- Opening the app displays its server status.
+- UDP discovery returns `SCREEN_IP_80`.
+- The existing bridge can discover the device.
+- `tools/list` returns valid schemas for the three initial tools.
+- `get_capabilities` reports the actual Tactility display dimensions.
+- `clear_screen` and `draw_text` visibly update the app.
+- Malformed JSON and unknown methods return JSON-RPC errors without crashing.
+- Repeated requests do not leak tasks, sockets, or request buffers.
+- App hiding/showing behavior is documented from a device test.
+
+## Phase 2 — Display tools
+
+Add:
+
+- `draw_raw_rgb565`
+- `POST /api/screen/raw`
+- `draw_color_bmp`
+- `draw_image`
+- `get_screenshot`
+- `set_backlight`
+- `set_screen_power`
+
+Display commands should target an app-owned LVGL canvas or image buffer. Direct
+panel access should only be used when the Tactility display HAL guarantees safe
+ownership and synchronization.
+
+Image preprocessing may remain in `mcp_bridge.py` initially. That avoids large
+PNG/JPEG decoders and unnecessary memory pressure on the ESP32-S3.
+
+## Phase 3 — Audio tools
+
+Port the working implementation from `Apps/AudioTest`:
+
+- `play_tone`
+- `record_voice`
+- `play_audio`
+- `play_audio_base64`
+
+Audio baseline:
+
+- 16 kHz
+- 16-bit signed PCM
+- mono
+- I2S device discovered through `device_find_by_name("i2s0")`
+
+Recordings should be streamed to the application's user-data directory instead
+of requiring one large fixed-duration RAM allocation.
+
+## Phase 4 — Hardware and system tools
+
+Add where supported:
+
+- `get_touch`
+- `get_battery`
+- `set_led`
+- `get_sensors`
+- `scan_ble`
+- `sync_time`
+- `read_file`
+- `write_file`
+- `download_file`
+
+File operations must:
+
+- resolve paths under the app user-data directory;
+- reject absolute paths and traversal such as `../`;
+- enforce practical request and file-size limits.
+
+`execute_python` is intentionally excluded. A future allow-listed diagnostic
+command tool may replace it if needed.
+
+## Phase 5 — Video streaming
+
+Add:
+
+- TCP frame server
+- UDP chunked frame server
+- stream activity timeout
+- `get_video_streaming_instructions`
+- `get_stream_stats`
+
+The new protocol should advertise the actual Tactility display dimensions and
+native color format. The old RLCD-specific 15,000-byte monochrome mapping may
+be offered only as an optional compatibility mode.
+
+Use preallocated buffers and avoid per-frame heap allocation.
+
+## Phase 6 — Dashboard and Hermes voice assistant
+
+Add:
+
+- five-second dashboard refresh;
+- MCP override mode;
+- an explicit local action to leave override mode;
+- Hermes WebSocket client;
+- touch-to-talk;
+- 16 kHz, 16-bit mono microphone streaming;
+- incoming PCM/WAV playback;
+- transcript, thinking, listening, and speaking UI states.
+
+## Compatibility notes
+
+- Keep the existing host bridge usable throughout development.
+- Preserve tool names and argument names unless a compatibility defect is
+  documented.
+- `draw_image` can continue to be host-preprocessed into PBM or RGB565.
+- Screenshot output may change from PBM to PNG/RGB565 if the bridge is updated
+  to understand both.
+- Hardware-specific tools should report support through `get_capabilities`.
+
+## Security and robustness limits
+
+The first implementation should define conservative limits for:
+
+- HTTP header size
+- JSON body size
+- base64 payload size
+- socket read timeout
+- simultaneous clients
+- filename length
+- file size
+- text length
+- drawing bounds
+- audio duration
+
+Only one display mutation should run at a time. Audio operations should also be
+serialized around the shared I2S device.
+
+## Build workflow
+
+From the TactilityApps repository:
+
+```bash
+. /Users/adolforeyna/esp/esp-idf/export.sh
+export TACTILITY_SDK_PATH=/Users/adolforeyna/.gemini/antigravity/scratch/tactility/release/TactilitySDK
+python3 tactility.py Apps/McpScreen build esp32s3 --local-sdk
+```
+
+## Immediate next task
+
+Implement Phase 1 as a minimal vertical slice:
+
+1. Scaffold the app and lifecycle.
+2. Add a small server-status UI.
+3. Add UDP discovery.
+4. Add HTTP and JSON-RPC parsing.
+5. Add `tools/list`.
+6. Add `get_capabilities`, `clear_screen`, and `draw_text`.
+7. Build.
+8. Run a host smoke test through the existing bridge.

Apps/McpScreen/README.md

@@ -0,0 +1,76 @@
+# MCP Screen
+
+Native Tactility port of the MicroPython MCP Screen firmware.
+
+Phase 1 provides:
+
+- JSON-RPC 2.0 over `POST /api/mcp` on port 80
+- `tools/list`
+- `get_capabilities`
+- `clear_screen`
+- `draw_text`
+
+Phase 2 adds:
+
+- `draw_raw_rgb565`
+- `POST /api/screen/raw`
+- `draw_color_bmp`
+- bridge-assisted PBM `draw_image`
+- PBM `get_screenshot`
+
+Backlight and screen-power controls are intentionally excluded.
+
+See `IMPLEMENTATION_PLAN.md` for the full roadmap.
+
+UDP discovery is temporarily unavailable to an external app because the
+Tactility 0.7.0-dev firmware does not export `lwip_recvfrom` and
+`lwip_sendto`. The existing MicroPython bridge remains compatible through its
+HTTP subnet-scan fallback.
+
+The HTTP worker uses a non-blocking listener and short client timeouts.
+`onHide` signals it and returns immediately; the worker owns the socket
+shutdown and then suspends itself outside the GUI lifecycle. It is reaped by
+the next `onShow`, or by `onDestroy` before Tactility unloads the external ELF.
+
+The MCP server is foreground-only: it starts in `onShow`, and port 80 closes
+within one short worker poll after `onHide`. It is intentionally unavailable
+whenever McpScreen is not the active screen.
+
+## Build
+
+```bash
+. /Users/adolforeyna/esp/esp-idf/export.sh
+export TACTILITY_SDK_PATH=/Users/adolforeyna/.gemini/antigravity/scratch/tactility/release/TactilitySDK
+python3 tactility.py Apps/McpScreen build esp32s3 --local-sdk
+```
+
+## Direct smoke test
+
+Replace the IP address with the device address:
+
+```bash
+curl -s http://DEVICE_IP/api/mcp \
+  -H 'Content-Type: application/json' \
+  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}'
+```
+
+```bash
+curl -s http://DEVICE_IP/api/mcp \
+  -H 'Content-Type: application/json' \
+  -d '{"jsonrpc":"2.0","id":2,"method":"tools/call","params":{"name":"draw_text","arguments":{"text":"Hello from MCP","x":20,"y":30,"size":2}}}'
+```
+
+The existing MicroPython host bridge can also be used unchanged:
+
+```bash
+python3 /Users/adolforeyna/Projects/MicroPython/test1/Screen/mcp_bridge.py
+```
+
+Or run the included Phase 2 smoke test:
+
+```bash
+python3 Apps/McpScreen/tools/smoke_test.py --ip DEVICE_IP --draw
+```
+
+The `--ip` argument is required until UDP discovery is available to external
+apps.

Apps/McpScreen/main/CMakeLists.txt

@@ -0,0 +1,8 @@
+file(GLOB_RECURSE SOURCE_FILES Source/*.c)
+set(CJSON_SOURCE "$ENV{IDF_PATH}/components/json/cJSON/cJSON.c")
+
+idf_component_register(
+    SRCS ${SOURCE_FILES} ${CJSON_SOURCE}
+    INCLUDE_DIRS Source "$ENV{IDF_PATH}/components/json/cJSON"
+    REQUIRES TactilitySDK lwip
+)

Apps/McpScreen/main/Source/DisplayTools.c

@@ -0,0 +1,337 @@
+#include "McpScreen.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <esp_log.h>
+#include <tt_lvgl.h>
+
+static const char* TAG = "DisplayTools";
+
+static bool ascii_space(uint8_t value) {
+    return value == ' ' || value == '\t' || value == '\r' ||
+           value == '\n' || value == '\f' || value == '\v';
+}
+
+static bool ascii_digit(uint8_t value) {
+    return value >= '0' && value <= '9';
+}
+
+static uint16_t read_le16(const uint8_t* value) {
+    return (uint16_t)value[0] | ((uint16_t)value[1] << 8);
+}
+
+static uint32_t read_le32(const uint8_t* value) {
+    return (uint32_t)value[0] |
+           ((uint32_t)value[1] << 8) |
+           ((uint32_t)value[2] << 16) |
+           ((uint32_t)value[3] << 24);
+}
+
+static bool display_ready(McpScreenState* state) {
+    return state != NULL &&
+           state->visible &&
+           state->draw_area != NULL &&
+           state->framebuffer != NULL &&
+           state->draw_width > 0 &&
+           state->draw_height > 0;
+}
+
+static uint16_t rgb888_to_rgb565(uint8_t red, uint8_t green, uint8_t blue) {
+    return (uint16_t)(((red & 0xF8) << 8) |
+                      ((green & 0xFC) << 3) |
+                      (blue >> 3));
+}
+
+static void put_pixel(McpScreenState* state, int x, int y, uint16_t color) {
+    if (x >= 0 && y >= 0 && x < state->draw_width && y < state->draw_height) {
+        state->framebuffer[(size_t)y * state->draw_width + x] = color;
+    }
+}
+
+bool mcp_ui_draw_rgb565_be(
+    McpScreenState* state,
+    const uint8_t* data,
+    size_t data_size,
+    int x,
+    int y,
+    int width,
+    int height
+) {
+    if (data == NULL || width <= 0 || height <= 0 ||
+        data_size < (size_t)width * height * 2 || !display_ready(state)) {
+        return false;
+    }
+
+    bool success = false;
+    if (tt_lvgl_lock(pdMS_TO_TICKS(2000))) {
+        if (display_ready(state)) {
+            for (int source_y = 0; source_y < height; ++source_y) {
+                int destination_y = y + source_y;
+                if (destination_y < 0 || destination_y >= state->draw_height) {
+                    continue;
+                }
+                for (int source_x = 0; source_x < width; ++source_x) {
+                    int destination_x = x + source_x;
+                    if (destination_x < 0 || destination_x >= state->draw_width) {
+                        continue;
+                    }
+                    size_t offset = ((size_t)source_y * width + source_x) * 2;
+                    uint16_t color = ((uint16_t)data[offset] << 8) | data[offset + 1];
+                    put_pixel(state, destination_x, destination_y, color);
+                }
+            }
+            lv_obj_invalidate(state->draw_area);
+            state->override_active = true;
+            success = true;
+        }
+        tt_lvgl_unlock();
+    }
+    return success;
+}
+
+bool mcp_ui_draw_bmp(
+    McpScreenState* state,
+    const uint8_t* data,
+    size_t data_size,
+    int x,
+    int y
+) {
+    if (data == NULL || data_size < 54 || !display_ready(state) ||
+        data[0] != 'B' || data[1] != 'M') {
+        return false;
+    }
+
+    uint32_t pixel_offset = read_le32(data + 10);
+    uint32_t dib_size = read_le32(data + 14);
+    int32_t width = (int32_t)read_le32(data + 18);
+    int32_t signed_height = (int32_t)read_le32(data + 22);
+    uint16_t planes = read_le16(data + 26);
+    uint16_t bits_per_pixel = read_le16(data + 28);
+    uint32_t compression = read_le32(data + 30);
+    if (dib_size < 40 || width <= 0 || signed_height == 0 || planes != 1 ||
+        (bits_per_pixel != 24 && bits_per_pixel != 32) || compression != 0) {
+        return false;
+    }
+
+    int height = signed_height < 0 ? -signed_height : signed_height;
+    bool top_down = signed_height < 0;
+    size_t row_stride = (((size_t)width * bits_per_pixel + 31) / 32) * 4;
+    if (pixel_offset > data_size ||
+        row_stride > data_size ||
+        (size_t)height > (data_size - pixel_offset) / row_stride) {
+        return false;
+    }
+
+    bool success = false;
+    if (tt_lvgl_lock(pdMS_TO_TICKS(2500))) {
+        if (display_ready(state)) {
+            size_t bytes_per_pixel = bits_per_pixel / 8;
+            for (int source_y = 0; source_y < height; ++source_y) {
+                int file_y = top_down ? source_y : (height - 1 - source_y);
+                const uint8_t* row = data + pixel_offset + (size_t)file_y * row_stride;
+                for (int source_x = 0; source_x < width; ++source_x) {
+                    const uint8_t* pixel = row + (size_t)source_x * bytes_per_pixel;
+                    put_pixel(
+                        state,
+                        x + source_x,
+                        y + source_y,
+                        rgb888_to_rgb565(pixel[2], pixel[1], pixel[0])
+                    );
+                }
+            }
+            lv_obj_invalidate(state->draw_area);
+            state->override_active = true;
+            success = true;
+        }
+        tt_lvgl_unlock();
+    }
+    return success;
+}
+
+static bool pbm_next_number(
+    const uint8_t* data,
+    size_t data_size,
+    size_t* offset,
+    int* result
+) {
+    while (*offset < data_size) {
+        if (data[*offset] == '#') {
+            while (*offset < data_size && data[*offset] != '\n') {
+                (*offset)++;
+            }
+        } else if (ascii_space(data[*offset])) {
+            (*offset)++;
+        } else {
+            break;
+        }
+    }
+    if (*offset >= data_size || !ascii_digit(data[*offset])) {
+        return false;
+    }
+
+    int value = 0;
+    while (*offset < data_size && ascii_digit(data[*offset])) {
+        value = value * 10 + (data[*offset] - '0');
+        (*offset)++;
+    }
+    *result = value;
+    return true;
+}
+
+bool mcp_ui_draw_pbm(
+    McpScreenState* state,
+    const uint8_t* data,
+    size_t data_size,
+    int x,
+    int y
+) {
+    if (data == NULL || data_size < 8 || !display_ready(state) ||
+        data[0] != 'P' || data[1] != '4') {
+        ESP_LOGE(
+            TAG,
+            "PBM precondition failed data=%p size=%u ready=%d magic=%02x%02x",
+            data,
+            (unsigned)data_size,
+            display_ready(state),
+            data_size > 0 ? data[0] : 0,
+            data_size > 1 ? data[1] : 0
+        );
+        return false;
+    }
+
+    size_t offset = 2;
+    int width = 0;
+    int height = 0;
+    if (!pbm_next_number(data, data_size, &offset, &width) ||
+        !pbm_next_number(data, data_size, &offset, &height) ||
+        width <= 0 || height <= 0) {
+        ESP_LOGE(TAG, "PBM dimension parse failed offset=%u w=%d h=%d", (unsigned)offset, width, height);
+        return false;
+    }
+    if (offset >= data_size || !ascii_space(data[offset])) {
+        ESP_LOGE(
+            TAG,
+            "PBM missing header separator offset=%u size=%u byte=%02x",
+            (unsigned)offset,
+            (unsigned)data_size,
+            offset < data_size ? data[offset] : 0
+        );
+        return false;
+    }
+    if (data[offset] == '\r' && offset + 1 < data_size && data[offset + 1] == '\n') {
+        offset += 2;
+    } else {
+        offset++;
+    }
+
+    size_t row_bytes = ((size_t)width + 7) / 8;
+    if (offset > data_size ||
+        (size_t)height > (data_size - offset) / row_bytes) {
+        ESP_LOGE(
+            TAG,
+            "PBM payload too small offset=%u size=%u row=%u h=%d",
+            (unsigned)offset,
+            (unsigned)data_size,
+            (unsigned)row_bytes,
+            height
+        );
+        return false;
+    }
+
+    bool success = false;
+    if (tt_lvgl_lock(pdMS_TO_TICKS(2000))) {
+        if (display_ready(state)) {
+            for (int source_y = 0; source_y < height; ++source_y) {
+                const uint8_t* row = data + offset + (size_t)source_y * row_bytes;
+                for (int source_x = 0; source_x < width; ++source_x) {
+                    bool black = (row[source_x >> 3] & (0x80 >> (source_x & 7))) != 0;
+                    put_pixel(state, x + source_x, y + source_y, black ? 0x0000 : 0xFFFF);
+                }
+            }
+            lv_obj_invalidate(state->draw_area);
+            state->override_active = true;
+            success = true;
+        }
+        tt_lvgl_unlock();
+    } else {
+        ESP_LOGE(TAG, "PBM LVGL lock timed out");
+    }
+    if (!success) ESP_LOGE(TAG, "PBM draw failed after lock ready=%d", display_ready(state));
+    return success;
+}
+
+static char* base64_encode(const uint8_t* input, size_t input_size) {
+    static const char alphabet[] =
+        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+    size_t output_size = ((input_size + 2) / 3) * 4;
+    char* output = malloc(output_size + 1);
+    if (output == NULL) {
+        return NULL;
+    }
+
+    size_t in = 0;
+    size_t out = 0;
+    while (in < input_size) {
+        uint32_t value = (uint32_t)input[in++] << 16;
+        bool have_second = in < input_size;
+        if (have_second) value |= (uint32_t)input[in++] << 8;
+        bool have_third = in < input_size;
+        if (have_third) value |= input[in++];
+
+        output[out++] = alphabet[(value >> 18) & 0x3F];
+        output[out++] = alphabet[(value >> 12) & 0x3F];
+        output[out++] = have_second ? alphabet[(value >> 6) & 0x3F] : '=';
+        output[out++] = have_third ? alphabet[value & 0x3F] : '=';
+    }
+    output[out] = '\0';
+    return output;
+}
+
+char* mcp_ui_get_screenshot_pbm_base64(McpScreenState* state) {
+    if (!display_ready(state)) {
+        return NULL;
+    }
+
+    size_t row_bytes = ((size_t)state->draw_width + 7) / 8;
+    char header[40];
+    int header_size = snprintf(
+        header,
+        sizeof(header),
+        "P4\n%u %u\n",
+        state->draw_width,
+        state->draw_height
+    );
+    size_t pbm_size = (size_t)header_size + row_bytes * state->draw_height;
+    uint8_t* pbm = calloc(1, pbm_size);
+    if (pbm == NULL) {
+        return NULL;
+    }
+    memcpy(pbm, header, header_size);
+
+    bool success = false;
+    if (tt_lvgl_lock(pdMS_TO_TICKS(2000))) {
+        if (display_ready(state)) {
+            for (int y = 0; y < state->draw_height; ++y) {
+                uint8_t* row = pbm + header_size + (size_t)y * row_bytes;
+                for (int x = 0; x < state->draw_width; ++x) {
+                    uint16_t color = state->framebuffer[(size_t)y * state->draw_width + x];
+                    int red = (color >> 11) & 0x1F;
+                    int green = (color >> 5) & 0x3F;
+                    int blue = color & 0x1F;
+                    int luminance = red * 2 + green * 3 + blue;
+                    if (luminance < 128) {
+                        row[x >> 3] |= (0x80 >> (x & 7));
+                    }
+                }
+            }
+            success = true;
+        }
+        tt_lvgl_unlock();
+    }
+
+    char* encoded = success ? base64_encode(pbm, pbm_size) : NULL;
+    free(pbm);
+    return encoded;
+}

Apps/McpScreen/main/Source/McpScreen.c

@@ -0,0 +1,287 @@
+#include "McpScreen.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <esp_log.h>
+#include <esp_heap_caps.h>
+#include <tt_lvgl.h>
+#include <tt_lvgl_toolbar.h>
+#include <tt_wifi.h>
+
+static const char* TAG = "McpScreen";
+
+static void set_label_text_locked(lv_obj_t* label, const char* text) {
+    if (label != NULL && lv_obj_is_valid(label)) {
+        lv_label_set_text(label, text);
+    }
+}
+
+void mcp_ui_set_server_status(McpScreenState* state, const char* status) {
+    if (state == NULL || !state->visible) {
+        return;
+    }
+
+    if (tt_lvgl_lock(pdMS_TO_TICKS(1000))) {
+        if (state->visible) {
+            set_label_text_locked(state->server_label, status);
+        }
+        tt_lvgl_unlock();
+    }
+}
+
+void mcp_ui_set_last_tool(McpScreenState* state, const char* tool) {
+    if (state == NULL || !state->visible) {
+        return;
+    }
+
+    if (tt_lvgl_lock(pdMS_TO_TICKS(1000))) {
+        if (state->visible && state->tool_label != NULL && lv_obj_is_valid(state->tool_label)) {
+            lv_label_set_text_fmt(state->tool_label, "Last: %s", tool);
+        }
+        tt_lvgl_unlock();
+    }
+}
+
+bool mcp_ui_clear(McpScreenState* state, int color) {
+    if (state == NULL || !state->visible || state->framebuffer == NULL) {
+        return false;
+    }
+
+    bool success = false;
+    if (tt_lvgl_lock(pdMS_TO_TICKS(1500))) {
+        if (state->visible && state->draw_area != NULL && lv_obj_is_valid(state->draw_area)) {
+            lv_obj_clean(state->draw_area);
+            uint16_t fill = color == 1 ? 0x0000 : 0xFFFF;
+            size_t pixel_count = (size_t)state->draw_width * state->draw_height;
+            for (size_t i = 0; i < pixel_count; ++i) {
+                state->framebuffer[i] = fill;
+            }
+            lv_obj_invalidate(state->draw_area);
+            state->draw_color = color;
+            state->override_active = true;
+            success = true;
+        }
+        tt_lvgl_unlock();
+    }
+    return success;
+}
+
+bool mcp_ui_draw_text(
+    McpScreenState* state,
+    const char* text,
+    int x,
+    int y,
+    int size
+) {
+    if (state == NULL || text == NULL || !state->visible) {
+        return false;
+    }
+
+    bool success = false;
+    if (tt_lvgl_lock(pdMS_TO_TICKS(1500))) {
+        if (state->visible && state->draw_area != NULL && lv_obj_is_valid(state->draw_area)) {
+            int max_x = state->draw_width > 0 ? state->draw_width - 1 : 0;
+            int max_y = state->draw_height > 0 ? state->draw_height - 1 : 0;
+            if (x < 0) x = 0;
+            if (y < 0) y = 0;
+            if (x > max_x) x = max_x;
+            if (y > max_y) y = max_y;
+
+            lv_obj_t* label = lv_label_create(state->draw_area);
+            lv_label_set_text(label, text);
+            lv_label_set_long_mode(label, LV_LABEL_LONG_WRAP);
+            lv_obj_set_width(label, LV_MAX(1, state->draw_width - x));
+            lv_obj_set_pos(label, x, y);
+
+            lv_obj_set_style_text_color(
+                label,
+                state->draw_color == 0 ? lv_color_black() : lv_color_white(),
+                LV_PART_MAIN
+            );
+
+#if LV_FONT_MONTSERRAT_24
+            if (size >= 2) {
+                lv_obj_set_style_text_font(label, &lv_font_montserrat_24, LV_PART_MAIN);
+            }
+#else
+            (void)size;
+#endif
+
+            state->override_active = true;
+            success = true;
+        }
+        tt_lvgl_unlock();
+    }
+    return success;
+}
+
+static void* create_data(void) {
+    McpScreenState* state = calloc(1, sizeof(McpScreenState));
+    if (state != NULL) {
+        state->http_socket = -1;
+        state->client_socket = -1;
+        state->discovery_socket = -1;
+    }
+    return state;
+}
+
+static void destroy_data(void* data) {
+    McpScreenState* state = data;
+    if (state != NULL && state->framebuffer != NULL) {
+        heap_caps_free(state->framebuffer);
+    }
+    free(state);
+}
+
+static void on_create(AppHandle app, void* data) {
+    McpScreenState* state = data;
+    state->app = app;
+}
+
+static void on_destroy(AppHandle app, void* data) {
+    (void)app;
+    mcp_services_stop((McpScreenState*)data);
+}
+
+static void on_show(AppHandle app, void* data, lv_obj_t* parent) {
+    McpScreenState* state = data;
+    ESP_LOGI(TAG, "onShow: starting foreground UI and MCP service");
+    state->visible = true;
+
+    lv_obj_remove_flag(parent, LV_OBJ_FLAG_SCROLLABLE);
+    lv_obj_set_flex_flow(parent, LV_FLEX_FLOW_COLUMN);
+    lv_obj_set_style_pad_all(parent, 0, LV_PART_MAIN);
+    lv_obj_set_style_pad_row(parent, 0, LV_PART_MAIN);
+
+    lv_obj_t* toolbar = tt_lvgl_toolbar_create_for_app(parent, app);
+    lv_obj_align(toolbar, LV_ALIGN_TOP_MID, 0, 0);
+
+    state->server_label = lv_label_create(toolbar);
+    lv_label_set_text(state->server_label, "MCP starting");
+    lv_obj_set_style_text_color(
+        state->server_label,
+        lv_palette_main(LV_PALETTE_ORANGE),
+        LV_PART_MAIN
+    );
+
+    state->tool_label = lv_label_create(toolbar);
+    lv_label_set_text(state->tool_label, "Last: none");
+
+    if (!mcp_services_start(state)) {
+        ESP_LOGE(TAG, "Failed to start foreground MCP service");
+        lv_label_set_text(state->server_label, "MCP start failed");
+        lv_obj_set_style_text_color(
+            state->server_label,
+            lv_palette_main(LV_PALETTE_RED),
+            LV_PART_MAIN
+        );
+    }
+
+    state->draw_area = lv_canvas_create(parent);
+    lv_obj_set_width(state->draw_area, LV_PCT(100));
+    lv_obj_set_flex_grow(state->draw_area, 1);
+    lv_obj_set_style_radius(state->draw_area, 0, LV_PART_MAIN);
+    lv_obj_set_style_border_width(state->draw_area, 0, LV_PART_MAIN);
+    lv_obj_set_style_pad_all(state->draw_area, 0, LV_PART_MAIN);
+    lv_obj_remove_flag(state->draw_area, LV_OBJ_FLAG_SCROLLABLE);
+
+    lv_display_t* display = lv_obj_get_display(parent);
+    state->display_width = lv_display_get_horizontal_resolution(display);
+    state->display_height = lv_display_get_vertical_resolution(display);
+
+    lv_obj_update_layout(parent);
+    state->draw_width = lv_obj_get_content_width(state->draw_area);
+    state->draw_height = lv_obj_get_content_height(state->draw_area);
+
+    size_t required_size = (size_t)state->draw_width * state->draw_height * sizeof(uint16_t);
+    if (state->framebuffer == NULL || state->framebuffer_size != required_size) {
+        if (state->framebuffer != NULL) {
+            heap_caps_free(state->framebuffer);
+            state->framebuffer = NULL;
+        }
+        state->framebuffer = heap_caps_malloc(required_size, MALLOC_CAP_SPIRAM | MALLOC_CAP_8BIT);
+        if (state->framebuffer == NULL) {
+            state->framebuffer = heap_caps_malloc(required_size, MALLOC_CAP_8BIT);
+        }
+        state->framebuffer_size = state->framebuffer == NULL ? 0 : required_size;
+    }
+
+    if (state->framebuffer == NULL) {
+        ESP_LOGE(TAG, "Failed to allocate %u-byte framebuffer", (unsigned)required_size);
+        lv_obj_t* error = lv_label_create(state->draw_area);
+        lv_label_set_text(error, "Framebuffer allocation failed");
+        lv_obj_center(error);
+        return;
+    }
+
+    lv_canvas_set_buffer(
+        state->draw_area,
+        state->framebuffer,
+        state->draw_width,
+        state->draw_height,
+        LV_COLOR_FORMAT_RGB565
+    );
+
+    if (!state->override_active) {
+        for (size_t i = 0; i < (size_t)state->draw_width * state->draw_height; ++i) {
+            state->framebuffer[i] = 0x10C3;
+        }
+        state->draw_color = 1;
+
+        lv_obj_t* title = lv_label_create(state->draw_area);
+        lv_label_set_text(title, "MCP Screen");
+        lv_obj_set_style_text_color(title, lv_color_white(), LV_PART_MAIN);
+#if LV_FONT_MONTSERRAT_24
+        lv_obj_set_style_text_font(title, &lv_font_montserrat_24, LV_PART_MAIN);
+#endif
+        lv_obj_align(title, LV_ALIGN_CENTER, 0, -55);
+
+        lv_obj_t* dimensions = lv_label_create(state->draw_area);
+        lv_label_set_text_fmt(
+            dimensions,
+            "%ux%u display\nHTTP :80\nDiscovery: bridge subnet scan",
+            state->display_width,
+            state->display_height
+        );
+        lv_obj_set_style_text_align(dimensions, LV_TEXT_ALIGN_CENTER, LV_PART_MAIN);
+        lv_obj_set_style_text_color(dimensions, lv_palette_lighten(LV_PALETTE_BLUE, 3), LV_PART_MAIN);
+        lv_obj_align(dimensions, LV_ALIGN_CENTER, 0, 0);
+
+        lv_obj_t* wifi = lv_label_create(state->draw_area);
+        lv_label_set_text_fmt(
+            wifi,
+            "Wi-Fi: %s",
+            tt_wifi_radio_state_to_string(tt_wifi_get_radio_state())
+        );
+        lv_obj_set_style_text_color(wifi, lv_color_white(), LV_PART_MAIN);
+        lv_obj_align(wifi, LV_ALIGN_CENTER, 0, 48);
+    }
+
+}
+
+static void on_hide(AppHandle app, void* data) {
+    (void)app;
+    McpScreenState* state = data;
+    ESP_LOGI(TAG, "onHide: stopping foreground MCP service");
+    state->visible = false;
+    mcp_services_hide(state);
+    state->draw_area = NULL;
+    state->server_label = NULL;
+    state->tool_label = NULL;
+}
+
+int main(int argc, char* argv[]) {
+    (void)argc;
+    (void)argv;
+    tt_app_register((AppRegistration) {
+        .createData = create_data,
+        .destroyData = destroy_data,
+        .onCreate = on_create,
+        .onDestroy = on_destroy,
+        .onShow = on_show,
+        .onHide = on_hide
+    });
+    return 0;
+}

Apps/McpScreen/main/Source/McpScreen.h

@@ -0,0 +1,76 @@
+#pragma once
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#include <freertos/FreeRTOS.h>
+#include <freertos/task.h>
+#include <lvgl.h>
+#include <tt_app.h>
+
+typedef struct {
+    volatile bool running;
+    volatile bool http_ready;
+    volatile bool http_exited;
+    volatile bool discovery_ready;
+    volatile bool visible;
+    volatile bool override_active;
+
+    int http_socket;
+    int client_socket;
+    int discovery_socket;
+    TaskHandle_t http_task;
+    TaskHandle_t discovery_task;
+
+    AppHandle app;
+    lv_obj_t* draw_area;
+    lv_obj_t* server_label;
+    lv_obj_t* tool_label;
+
+    uint16_t* framebuffer;
+    size_t framebuffer_size;
+    uint16_t display_width;
+    uint16_t display_height;
+    uint16_t draw_width;
+    uint16_t draw_height;
+    int draw_color;
+} McpScreenState;
+
+bool mcp_services_start(McpScreenState* state);
+void mcp_services_hide(McpScreenState* state);
+void mcp_services_stop(McpScreenState* state);
+
+void mcp_ui_set_server_status(McpScreenState* state, const char* status);
+void mcp_ui_set_last_tool(McpScreenState* state, const char* tool);
+bool mcp_ui_clear(McpScreenState* state, int color);
+bool mcp_ui_draw_text(
+    McpScreenState* state,
+    const char* text,
+    int x,
+    int y,
+    int size
+);
+bool mcp_ui_draw_rgb565_be(
+    McpScreenState* state,
+    const uint8_t* data,
+    size_t data_size,
+    int x,
+    int y,
+    int width,
+    int height
+);
+bool mcp_ui_draw_bmp(
+    McpScreenState* state,
+    const uint8_t* data,
+    size_t data_size,
+    int x,
+    int y
+);
+bool mcp_ui_draw_pbm(
+    McpScreenState* state,
+    const uint8_t* data,
+    size_t data_size,
+    int x,
+    int y
+);
+char* mcp_ui_get_screenshot_pbm_base64(McpScreenState* state);

Apps/McpScreen/main/Source/McpServer.c

@@ -0,0 +1,820 @@
+#include "McpScreen.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <cJSON.h>
+#include <esp_log.h>
+#include <freertos/FreeRTOS.h>
+#include <freertos/task.h>
+#include <lwip/inet.h>
+#include <lwip/sockets.h>
+
+#define MCP_HTTP_PORT 80
+#define MCP_HEADER_LIMIT 2048
+#define MCP_JSON_BODY_LIMIT (256 * 1024)
+#define MCP_RAW_BODY_LIMIT (512 * 1024)
+#define MCP_RESPONSE_LIMIT (64 * 1024)
+
+static const char* TAG = "McpServer";
+
+static const char* TOOLS_JSON =
+    "["
+    "{"
+      "\"name\":\"get_capabilities\","
+      "\"description\":\"Get the Tactility display capabilities.\","
+      "\"inputSchema\":{\"type\":\"object\",\"properties\":{}}"
+    "},"
+    "{"
+      "\"name\":\"clear_screen\","
+      "\"description\":\"Clear the MCP drawing area to white (0) or black (1).\","
+      "\"inputSchema\":{"
+        "\"type\":\"object\","
+        "\"properties\":{\"color\":{\"type\":\"integer\",\"enum\":[0,1]}},"
+        "\"required\":[\"color\"]"
+      "}"
+    "},"
+    "{"
+      "\"name\":\"draw_text\","
+      "\"description\":\"Draw text in the MCP drawing area at x,y coordinates.\","
+      "\"inputSchema\":{"
+        "\"type\":\"object\","
+        "\"properties\":{"
+          "\"text\":{\"type\":\"string\"},"
+          "\"x\":{\"type\":\"integer\"},"
+          "\"y\":{\"type\":\"integer\"},"
+          "\"size\":{\"type\":\"integer\",\"enum\":[1,2],\"default\":1}"
+        "},"
+        "\"required\":[\"text\",\"x\",\"y\"]"
+      "}"
+    "},"
+    "{"
+      "\"name\":\"draw_image\","
+      "\"description\":\"Draw a bridge-preprocessed binary PBM image.\","
+      "\"inputSchema\":{"
+        "\"type\":\"object\","
+        "\"properties\":{"
+          "\"pbm_base64\":{\"type\":\"string\"},"
+          "\"x\":{\"type\":\"integer\",\"default\":0},"
+          "\"y\":{\"type\":\"integer\",\"default\":0},"
+          "\"dither\":{\"type\":\"boolean\",\"default\":true}"
+        "},"
+        "\"required\":[\"pbm_base64\"]"
+      "}"
+    "},"
+    "{"
+      "\"name\":\"draw_color_bmp\","
+      "\"description\":\"Draw an uncompressed 24-bit or 32-bit BMP image.\","
+      "\"inputSchema\":{"
+        "\"type\":\"object\","
+        "\"properties\":{"
+          "\"bmp_base64\":{\"type\":\"string\"},"
+          "\"x\":{\"type\":\"integer\",\"default\":0},"
+          "\"y\":{\"type\":\"integer\",\"default\":0}"
+        "},"
+        "\"required\":[\"bmp_base64\"]"
+      "}"
+    "},"
+    "{"
+      "\"name\":\"draw_raw_rgb565\","
+      "\"description\":\"Draw big-endian raw RGB565 pixels.\","
+      "\"inputSchema\":{"
+        "\"type\":\"object\","
+        "\"properties\":{"
+          "\"rgb565_base64\":{\"type\":\"string\"},"
+          "\"x\":{\"type\":\"integer\"},"
+          "\"y\":{\"type\":\"integer\"},"
+          "\"w\":{\"type\":\"integer\"},"
+          "\"h\":{\"type\":\"integer\"}"
+        "},"
+        "\"required\":[\"rgb565_base64\",\"x\",\"y\",\"w\",\"h\"]"
+      "}"
+    "},"
+    "{"
+      "\"name\":\"get_screenshot\","
+      "\"description\":\"Capture the MCP framebuffer as a PBM image.\","
+      "\"inputSchema\":{\"type\":\"object\",\"properties\":{}}"
+    "}"
+    "]";
+
+static int base64_value(char character) {
+    if (character >= 'A' && character <= 'Z') return character - 'A';
+    if (character >= 'a' && character <= 'z') return character - 'a' + 26;
+    if (character >= '0' && character <= '9') return character - '0' + 52;
+    if (character == '+') return 62;
+    if (character == '/') return 63;
+    return -1;
+}
+
+static uint8_t* base64_decode(const char* input, size_t* output_size) {
+    if (input == NULL || output_size == NULL) {
+        return NULL;
+    }
+
+    const char* payload = input;
+    const char* marker = strstr(input, ";base64,");
+    if (marker != NULL) {
+        payload = marker + 8;
+    }
+
+    size_t input_size = strlen(payload);
+    uint8_t* output = malloc((input_size / 4) * 3 + 3);
+    if (output == NULL) {
+        return NULL;
+    }
+
+    uint32_t accumulator = 0;
+    int bits = 0;
+    size_t written = 0;
+    for (size_t index = 0; index < input_size; ++index) {
+        char character = payload[index];
+        if (character == '=') {
+            break;
+        }
+        int value = base64_value(character);
+        if (value < 0) {
+            if (character == '\r' || character == '\n' ||
+                character == ' ' || character == '\t') {
+                continue;
+            }
+            free(output);
+            return NULL;
+        }
+        accumulator = (accumulator << 6) | (uint32_t)value;
+        bits += 6;
+        if (bits >= 8) {
+            bits -= 8;
+            output[written++] = (uint8_t)((accumulator >> bits) & 0xFF);
+        }
+    }
+    *output_size = written;
+    return output;
+}
+
+static void close_socket(int* socket_fd) {
+    if (socket_fd != NULL && *socket_fd >= 0) {
+        close(*socket_fd);
+        *socket_fd = -1;
+    }
+}
+
+static bool send_all(int socket_fd, const char* data, size_t length) {
+    size_t sent_total = 0;
+    while (sent_total < length) {
+        int sent = send(socket_fd, data + sent_total, length - sent_total, 0);
+        if (sent <= 0) {
+            return false;
+        }
+        sent_total += (size_t)sent;
+    }
+    return true;
+}
+
+static cJSON* make_error(cJSON* id, int code, const char* message) {
+    cJSON* root = cJSON_CreateObject();
+    cJSON_AddStringToObject(root, "jsonrpc", "2.0");
+
+    cJSON* error = cJSON_AddObjectToObject(root, "error");
+    cJSON_AddNumberToObject(error, "code", code);
+    cJSON_AddStringToObject(error, "message", message);
+
+    if (id != NULL) {
+        cJSON_AddItemToObject(root, "id", cJSON_Duplicate(id, true));
+    } else {
+        cJSON_AddNullToObject(root, "id");
+    }
+    return root;
+}
+
+static cJSON* make_tool_result(cJSON* id, const char* text) {
+    cJSON* root = cJSON_CreateObject();
+    cJSON_AddStringToObject(root, "jsonrpc", "2.0");
+
+    cJSON* result = cJSON_AddObjectToObject(root, "result");
+    cJSON* content = cJSON_AddArrayToObject(result, "content");
+    cJSON* item = cJSON_CreateObject();
+    cJSON_AddStringToObject(item, "type", "text");
+    cJSON_AddStringToObject(item, "text", text);
+    cJSON_AddItemToArray(content, item);
+
+    if (id != NULL) {
+        cJSON_AddItemToObject(root, "id", cJSON_Duplicate(id, true));
+    } else {
+        cJSON_AddNullToObject(root, "id");
+    }
+    return root;
+}
+
+static cJSON* handle_tool_call(McpScreenState* state, cJSON* id, cJSON* params) {
+    if (!cJSON_IsObject(params)) {
+        return make_error(id, -32602, "Invalid params");
+    }
+
+    cJSON* name_item = cJSON_GetObjectItemCaseSensitive(params, "name");
+    cJSON* arguments = cJSON_GetObjectItemCaseSensitive(params, "arguments");
+    if (!cJSON_IsString(name_item) || name_item->valuestring == NULL) {
+        return make_error(id, -32602, "Missing tool name");
+    }
+    if (arguments != NULL && !cJSON_IsObject(arguments)) {
+        return make_error(id, -32602, "Tool arguments must be an object");
+    }
+
+    const char* name = name_item->valuestring;
+    mcp_ui_set_last_tool(state, name);
+
+    if (strcmp(name, "get_capabilities") == 0) {
+        char capabilities[320];
+        uint16_t width = state->draw_width > 0 ? state->draw_width : state->display_width;
+        uint16_t height = state->draw_height > 0 ? state->draw_height : state->display_height;
+        snprintf(
+            capabilities,
+            sizeof(capabilities),
+            "{\"color\":true,\"width\":%u,\"height\":%u,"
+            "\"formats\":[\"rgb565_base64\",\"bmp_base64\",\"pbm_base64\"],"
+            "\"platform\":\"tactility\",\"appVersion\":\"0.1.0\","
+            "\"uiVisible\":%s}",
+            width,
+            height,
+            state->visible ? "true" : "false"
+        );
+        return make_tool_result(id, capabilities);
+    }
+
+    if (strcmp(name, "clear_screen") == 0) {
+        cJSON* color_item = cJSON_GetObjectItemCaseSensitive(arguments, "color");
+        if (!cJSON_IsNumber(color_item) ||
+            (color_item->valueint != 0 && color_item->valueint != 1)) {
+            return make_error(id, -32602, "color must be 0 or 1");
+        }
+        if (!mcp_ui_clear(state, color_item->valueint)) {
+            return make_error(id, -32010, "MCP Screen app is not visible");
+        }
+        return make_tool_result(id, "Screen cleared.");
+    }
+
+    if (strcmp(name, "draw_text") == 0) {
+        cJSON* text_item = cJSON_GetObjectItemCaseSensitive(arguments, "text");
+        cJSON* x_item = cJSON_GetObjectItemCaseSensitive(arguments, "x");
+        cJSON* y_item = cJSON_GetObjectItemCaseSensitive(arguments, "y");
+        cJSON* size_item = cJSON_GetObjectItemCaseSensitive(arguments, "size");
+
+        if (!cJSON_IsString(text_item) || text_item->valuestring == NULL ||
+            !cJSON_IsNumber(x_item) || !cJSON_IsNumber(y_item)) {
+            return make_error(id, -32602, "draw_text requires text, x, and y");
+        }
+        if (strlen(text_item->valuestring) > 512) {
+            return make_error(id, -32602, "text exceeds 512 characters");
+        }
+
+        int size = cJSON_IsNumber(size_item) ? size_item->valueint : 1;
+        if (size != 1 && size != 2) {
+            return make_error(id, -32602, "size must be 1 or 2");
+        }
+
+        if (!mcp_ui_draw_text(
+                state,
+                text_item->valuestring,
+                x_item->valueint,
+                y_item->valueint,
+                size)) {
+            return make_error(id, -32010, "MCP Screen app is not visible");
+        }
+
+        char message[160];
+        snprintf(
+            message,
+            sizeof(message),
+            "Successfully drew text at (%d, %d) with size %d.",
+            x_item->valueint,
+            y_item->valueint,
+            size
+        );
+        return make_tool_result(id, message);
+    }
+
+    if (strcmp(name, "draw_raw_rgb565") == 0) {
+        cJSON* encoded_item = cJSON_GetObjectItemCaseSensitive(arguments, "rgb565_base64");
+        cJSON* x_item = cJSON_GetObjectItemCaseSensitive(arguments, "x");
+        cJSON* y_item = cJSON_GetObjectItemCaseSensitive(arguments, "y");
+        cJSON* width_item = cJSON_GetObjectItemCaseSensitive(arguments, "w");
+        cJSON* height_item = cJSON_GetObjectItemCaseSensitive(arguments, "h");
+        if (!cJSON_IsString(encoded_item) || !cJSON_IsNumber(x_item) ||
+            !cJSON_IsNumber(y_item) || !cJSON_IsNumber(width_item) ||
+            !cJSON_IsNumber(height_item)) {
+            return make_error(id, -32602, "draw_raw_rgb565 requires rgb565_base64, x, y, w, and h");
+        }
+
+        size_t decoded_size = 0;
+        uint8_t* decoded = base64_decode(encoded_item->valuestring, &decoded_size);
+        if (decoded == NULL) {
+            return make_error(id, -32602, "Invalid RGB565 base64 data");
+        }
+        bool drawn = mcp_ui_draw_rgb565_be(
+            state,
+            decoded,
+            decoded_size,
+            x_item->valueint,
+            y_item->valueint,
+            width_item->valueint,
+            height_item->valueint
+        );
+        free(decoded);
+        return drawn
+            ? make_tool_result(id, "Raw RGB565 data displayed successfully.")
+            : make_error(id, -32010, "Failed to draw RGB565 data");
+    }
+
+    if (strcmp(name, "draw_color_bmp") == 0) {
+        cJSON* encoded_item = cJSON_GetObjectItemCaseSensitive(arguments, "bmp_base64");
+        cJSON* x_item = cJSON_GetObjectItemCaseSensitive(arguments, "x");
+        cJSON* y_item = cJSON_GetObjectItemCaseSensitive(arguments, "y");
+        if (!cJSON_IsString(encoded_item)) {
+            return make_error(id, -32602, "Missing bmp_base64");
+        }
+        size_t decoded_size = 0;
+        uint8_t* decoded = base64_decode(encoded_item->valuestring, &decoded_size);
+        if (decoded == NULL) {
+            return make_error(id, -32602, "Invalid BMP base64 data");
+        }
+        bool drawn = mcp_ui_draw_bmp(
+            state,
+            decoded,
+            decoded_size,
+            cJSON_IsNumber(x_item) ? x_item->valueint : 0,
+            cJSON_IsNumber(y_item) ? y_item->valueint : 0
+        );
+        free(decoded);
+        return drawn
+            ? make_tool_result(id, "Color BMP image displayed successfully.")
+            : make_error(id, -32602, "Unsupported or invalid BMP image");
+    }
+
+    if (strcmp(name, "draw_image") == 0) {
+        cJSON* encoded_item = cJSON_GetObjectItemCaseSensitive(arguments, "pbm_base64");
+        cJSON* x_item = cJSON_GetObjectItemCaseSensitive(arguments, "x");
+        cJSON* y_item = cJSON_GetObjectItemCaseSensitive(arguments, "y");
+        if (!cJSON_IsString(encoded_item)) {
+            return make_error(
+                id,
+                -32602,
+                "draw_image requires bridge-preprocessed pbm_base64"
+            );
+        }
+        size_t decoded_size = 0;
+        uint8_t* decoded = base64_decode(encoded_item->valuestring, &decoded_size);
+        if (decoded == NULL) {
+            return make_error(id, -32602, "Invalid PBM base64 data");
+        }
+        bool drawn = mcp_ui_draw_pbm(
+            state,
+            decoded,
+            decoded_size,
+            cJSON_IsNumber(x_item) ? x_item->valueint : 0,
+            cJSON_IsNumber(y_item) ? y_item->valueint : 0
+        );
+        free(decoded);
+        return drawn
+            ? make_tool_result(id, "Image displayed successfully.")
+            : make_error(id, -32602, "Unsupported or invalid PBM image");
+    }
+
+    if (strcmp(name, "get_screenshot") == 0) {
+        char* encoded = mcp_ui_get_screenshot_pbm_base64(state);
+        if (encoded == NULL) {
+            return make_error(id, -32010, "Screenshot capture failed");
+        }
+        size_t result_size = strlen(encoded) + 17;
+        char* result = malloc(result_size);
+        if (result == NULL) {
+            free(encoded);
+            return make_error(id, -32603, "Out of memory");
+        }
+        snprintf(result, result_size, "__PBM_BASE64__:%s", encoded);
+        cJSON* response = make_tool_result(id, result);
+        free(result);
+        free(encoded);
+        return response;
+    }
+
+    return make_error(id, -32602, "Unknown tool");
+}
+
+static cJSON* handle_rpc(McpScreenState* state, const char* body) {
+    cJSON* request = cJSON_Parse(body);
+    if (request == NULL) {
+        return make_error(NULL, -32700, "Parse error");
+    }
+
+    cJSON* id = cJSON_GetObjectItemCaseSensitive(request, "id");
+    cJSON* jsonrpc = cJSON_GetObjectItemCaseSensitive(request, "jsonrpc");
+    cJSON* method = cJSON_GetObjectItemCaseSensitive(request, "method");
+    cJSON* params = cJSON_GetObjectItemCaseSensitive(request, "params");
+
+    if (!cJSON_IsObject(request) ||
+        !cJSON_IsString(jsonrpc) ||
+        strcmp(jsonrpc->valuestring, "2.0") != 0 ||
+        !cJSON_IsString(method)) {
+        cJSON* response = make_error(id, -32600, "Invalid Request");
+        cJSON_Delete(request);
+        return response;
+    }
+
+    cJSON* response = NULL;
+    if (strcmp(method->valuestring, "tools/list") == 0) {
+        cJSON* tools = cJSON_Parse(TOOLS_JSON);
+        if (tools == NULL) {
+            response = make_error(id, -32603, "Failed to construct tool list");
+        } else {
+            response = cJSON_CreateObject();
+            cJSON_AddStringToObject(response, "jsonrpc", "2.0");
+            cJSON* result = cJSON_AddObjectToObject(response, "result");
+            cJSON_AddItemToObject(result, "tools", tools);
+            if (id != NULL) {
+                cJSON_AddItemToObject(response, "id", cJSON_Duplicate(id, true));
+            } else {
+                cJSON_AddNullToObject(response, "id");
+            }
+        }
+    } else if (strcmp(method->valuestring, "tools/call") == 0) {
+        response = handle_tool_call(state, id, params);
+    } else {
+        response = make_error(id, -32601, "Method not found");
+    }
+
+    cJSON_Delete(request);
+    return response;
+}
+
+static int find_header_end(const char* buffer, int length) {
+    for (int i = 0; i <= length - 4; ++i) {
+        if (buffer[i] == '\r' && buffer[i + 1] == '\n' &&
+            buffer[i + 2] == '\r' && buffer[i + 3] == '\n') {
+            return i + 4;
+        }
+    }
+    return -1;
+}
+
+static int parse_content_length(const char* headers) {
+    const char* cursor = headers;
+    while ((cursor = strstr(cursor, "\r\n")) != NULL) {
+        cursor += 2;
+        if (strncasecmp(cursor, "Content-Length:", 15) == 0) {
+            return atoi(cursor + 15);
+        }
+    }
+    return 0;
+}
+
+static void send_http_response(int client, int status, const char* content_type, const char* body) {
+    const char* status_text = status == 200 ? "OK" :
+                              status == 404 ? "Not Found" :
+                              status == 405 ? "Method Not Allowed" :
+                              status == 413 ? "Payload Too Large" :
+                              "Bad Request";
+    char header[320];
+    int body_length = body == NULL ? 0 : (int)strlen(body);
+    int header_length = snprintf(
+        header,
+        sizeof(header),
+        "HTTP/1.1 %d %s\r\n"
+        "Content-Type: %s\r\n"
+        "Content-Length: %d\r\n"
+        "Connection: close\r\n"
+        "Access-Control-Allow-Origin: *\r\n"
+        "\r\n",
+        status,
+        status_text,
+        content_type,
+        body_length
+    );
+    send_all(client, header, (size_t)header_length);
+    if (body_length > 0) {
+        send_all(client, body, (size_t)body_length);
+    }
+}
+
+static int query_integer(const char* path, const char* name, int default_value) {
+    const char* query = strchr(path, '?');
+    if (query == NULL) {
+        return default_value;
+    }
+    query++;
+    size_t name_size = strlen(name);
+    while (*query != '\0') {
+        if (strncmp(query, name, name_size) == 0 && query[name_size] == '=') {
+            return atoi(query + name_size + 1);
+        }
+        query = strchr(query, '&');
+        if (query == NULL) {
+            break;
+        }
+        query++;
+    }
+    return default_value;
+}
+
+static void handle_http_client(McpScreenState* state, int client) {
+    struct timeval timeout = { .tv_sec = 0, .tv_usec = 250000 };
+    setsockopt(client, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(timeout));
+    setsockopt(client, SOL_SOCKET, SO_SNDTIMEO, &timeout, sizeof(timeout));
+
+    char* headers = calloc(1, MCP_HEADER_LIMIT + 1);
+    if (headers == NULL) {
+        send_http_response(client, 400, "text/plain", "Out of memory");
+        return;
+    }
+
+    int received = 0;
+    int header_end = -1;
+    while (state->running && received < MCP_HEADER_LIMIT) {
+        int count = recv(client, headers + received, MCP_HEADER_LIMIT - received, 0);
+        if (count <= 0) {
+            free(headers);
+            return;
+        }
+        received += count;
+        header_end = find_header_end(headers, received);
+        if (header_end >= 0) {
+            break;
+        }
+    }
+
+    if (!state->running) {
+        free(headers);
+        return;
+    }
+
+    if (header_end < 0) {
+        send_http_response(client, 400, "text/plain", "Invalid HTTP headers");
+        free(headers);
+        return;
+    }
+
+    headers[header_end - 4] = '\0';
+    char method[12] = {0};
+    char path[128] = {0};
+    if (sscanf(headers, "%11s %127s", method, path) != 2) {
+        send_http_response(client, 400, "text/plain", "Invalid request line");
+        free(headers);
+        return;
+    }
+
+    if (strcmp(method, "POST") != 0) {
+        send_http_response(client, 405, "text/plain", "POST required");
+        free(headers);
+        return;
+    }
+
+    bool is_mcp = strcmp(path, "/api/mcp") == 0;
+    bool is_raw = strncmp(path, "/api/screen/raw", 15) == 0;
+    if (!is_mcp && !is_raw) {
+        send_http_response(client, 404, "text/plain", "Not found");
+        free(headers);
+        return;
+    }
+
+    int body_limit = is_raw ? MCP_RAW_BODY_LIMIT : MCP_JSON_BODY_LIMIT;
+    int content_length = parse_content_length(headers);
+    if (content_length <= 0 || content_length > body_limit) {
+        send_http_response(
+            client,
+            content_length > body_limit ? 413 : 400,
+            "text/plain",
+            "Invalid Content-Length"
+        );
+        free(headers);
+        return;
+    }
+
+    uint8_t* body = malloc((size_t)content_length + (is_mcp ? 1 : 0));
+    if (body == NULL) {
+        send_http_response(client, 400, "text/plain", "Out of memory");
+        free(headers);
+        return;
+    }
+
+    int body_received = received - header_end;
+    if (body_received > content_length) {
+        body_received = content_length;
+    }
+    memcpy(body, headers + header_end, body_received);
+    free(headers);
+
+    while (state->running && body_received < content_length) {
+        int count = recv(client, body + body_received, content_length - body_received, 0);
+        if (count <= 0) {
+            send_http_response(client, 400, "text/plain", "Incomplete request body");
+            free(body);
+            return;
+        }
+        body_received += count;
+    }
+
+    if (!state->running || body_received < content_length) {
+        free(body);
+        return;
+    }
+
+    if (is_raw) {
+        int x = query_integer(path, "x", 0);
+        int y = query_integer(path, "y", 0);
+        int width = query_integer(path, "w", state->draw_width);
+        int height = query_integer(path, "h", state->draw_height);
+        bool valid_size = width > 0 && height > 0 &&
+                          (size_t)width * height * 2 == (size_t)content_length;
+        bool drawn = valid_size && mcp_ui_draw_rgb565_be(
+            state,
+            body,
+            content_length,
+            x,
+            y,
+            width,
+            height
+        );
+        send_http_response(
+            client,
+            drawn ? 200 : 400,
+            "text/plain",
+            drawn ? "OK" : "Invalid RGB565 payload"
+        );
+    } else {
+        body[content_length] = '\0';
+        cJSON* response = handle_rpc(state, (const char*)body);
+        char* response_text = cJSON_PrintUnformatted(response);
+        if (response_text != NULL && strlen(response_text) <= MCP_RESPONSE_LIMIT) {
+            send_http_response(client, 200, "application/json", response_text);
+        } else {
+            send_http_response(client, 400, "text/plain", "Response serialization failed");
+        }
+        cJSON_free(response_text);
+        cJSON_Delete(response);
+    }
+
+    free(body);
+}
+
+static void http_task(void* argument) {
+    McpScreenState* state = argument;
+    state->http_exited = false;
+    int server = socket(AF_INET, SOCK_STREAM, IPPROTO_IP);
+    if (server < 0) {
+        ESP_LOGE(TAG, "Failed to create HTTP socket: errno=%d", errno);
+        state->http_ready = false;
+        mcp_ui_set_server_status(state, "MCP socket error");
+        goto suspend_for_owner;
+    }
+    state->http_socket = server;
+
+    int reuse = 1;
+    setsockopt(server, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(reuse));
+
+    struct sockaddr_in address = {
+        .sin_family = AF_INET,
+        .sin_port = htons(MCP_HTTP_PORT),
+        .sin_addr.s_addr = htonl(INADDR_ANY)
+    };
+
+    if (bind(server, (struct sockaddr*)&address, sizeof(address)) != 0 ||
+        listen(server, 3) != 0) {
+        ESP_LOGE(TAG, "Failed to bind/listen on TCP %d: errno=%d", MCP_HTTP_PORT, errno);
+        state->http_ready = false;
+        mcp_ui_set_server_status(state, "MCP bind error");
+        close_socket(&state->http_socket);
+        goto suspend_for_owner;
+    }
+
+    int flags = fcntl(server, F_GETFL, 0);
+    if (flags < 0 || fcntl(server, F_SETFL, flags | O_NONBLOCK) < 0) {
+        ESP_LOGE(TAG, "Failed to make HTTP listener non-blocking: errno=%d", errno);
+        state->http_ready = false;
+        mcp_ui_set_server_status(state, "MCP socket config error");
+        close_socket(&state->http_socket);
+        goto suspend_for_owner;
+    }
+
+    ESP_LOGI(TAG, "HTTP MCP server listening on port %d", MCP_HTTP_PORT);
+    state->http_ready = true;
+    mcp_ui_set_server_status(state, "MCP :80 ready");
+
+    while (state->running) {
+        struct sockaddr_storage source;
+        socklen_t source_length = sizeof(source);
+        int client = accept(server, (struct sockaddr*)&source, &source_length);
+        if (client < 0) {
+            if (!state->running) {
+                break;
+            }
+            vTaskDelay(pdMS_TO_TICKS(50));
+            continue;
+        }
+        state->client_socket = client;
+        handle_http_client(state, client);
+        close_socket(&state->client_socket);
+    }
+
+    close_socket(&state->client_socket);
+    close_socket(&state->http_socket);
+    state->http_ready = false;
+    
+suspend_for_owner:
+    /*
+     * External-app code must not continue after Tactility unloads the ELF.
+     * Signal completion, then suspend in FreeRTOS code. onDestroy owns the
+     * final vTaskDelete() and will not return until the worker is gone.
+     */
+    state->http_exited = true;
+    vTaskSuspend(NULL);
+    vTaskDelete(NULL);
+}
+
+bool mcp_services_start(McpScreenState* state) {
+    if (state == NULL || state->running) {
+        ESP_LOGE(TAG, "Service start rejected state=%p running=%d", state, state != NULL && state->running);
+        return false;
+    }
+
+    /*
+     * onHide only requests shutdown because it runs in Tactility's GUI
+     * lifecycle. Reap the worker after it has reached its safe suspended
+     * state before starting a new foreground server.
+     */
+    if (state->http_task != NULL) {
+        if (!state->http_exited) {
+            ESP_LOGE(TAG, "Previous HTTP worker is still stopping");
+            return false;
+        }
+        vTaskDelete(state->http_task);
+        state->http_task = NULL;
+    }
+
+    state->running = true;
+    state->http_exited = false;
+    state->http_socket = -1;
+    state->client_socket = -1;
+    BaseType_t http_result = xTaskCreate(
+        http_task,
+        "mcp_http",
+        8192,
+        state,
+        4,
+        &state->http_task
+    );
+    /*
+     * UDP discovery requires lwip_recvfrom/lwip_sendto. Tactility 0.7.0-dev
+     * currently does not export those symbols to external ELF apps. The
+     * existing host bridge remains compatible through its HTTP subnet-scan
+     * fallback. Re-enable discovery when those symbols are exported.
+     */
+    state->discovery_ready = false;
+    state->discovery_task = NULL;
+
+    if (http_result != pdPASS) {
+        ESP_LOGE(TAG, "Failed to create MCP service tasks");
+        mcp_services_stop(state);
+        return false;
+    }
+    return true;
+}
+
+void mcp_services_hide(McpScreenState* state) {
+    if (state == NULL) {
+        return;
+    }
+
+    state->running = false;
+    state->http_ready = false;
+    state->discovery_ready = false;
+}
+
+void mcp_services_stop(McpScreenState* state) {
+    if (state == NULL) {
+        return;
+    }
+
+    mcp_services_hide(state);
+
+    for (int attempt = 0; attempt < 80; ++attempt) {
+        if (state->http_task == NULL || state->http_exited) {
+            break;
+        }
+        vTaskDelay(pdMS_TO_TICKS(10));
+    }
+
+    if (state->http_task != NULL) {
+        /*
+         * Normal path: the non-blocking worker has closed its sockets and
+         * suspended itself. The bounded fallback guarantees that no
+         * external-ELF instruction survives onDestroy.
+         */
+        vTaskDelete(state->http_task);
+        state->http_task = NULL;
+    }
+    close_socket(&state->http_socket);
+    close_socket(&state->client_socket);
+    close_socket(&state->discovery_socket);
+    state->http_exited = true;
+}

Apps/McpScreen/manifest.properties

@@ -0,0 +1,10 @@
+[manifest]
+version=0.1
+[target]
+sdk=0.7.0-dev
+platforms=esp32s3
+[app]
+id=one.tactility.mcpscreen
+versionName=0.1.0
+versionCode=1
+name=MCP Screen

Apps/McpScreen/tools/smoke_test.py

@@ -0,0 +1,228 @@
+#!/usr/bin/env python3
+"""Host smoke test for the Tactility MCP Screen Phase 2 API."""
+
+import argparse
+import base64
+import json
+import socket
+import struct
+import urllib.request
+
+
+def discover(timeout: float = 2.0) -> str | None:
+    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+    sock.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
+    sock.settimeout(timeout)
+    try:
+        sock.sendto(b"DISCOVER_SCREEN", ("255.255.255.255", 5000))
+        data, address = sock.recvfrom(128)
+        if data == b"SCREEN_IP_80":
+            return address[0]
+    except TimeoutError:
+        return None
+    finally:
+        sock.close()
+    return None
+
+
+def rpc(ip: str, request_id: int, method: str, params: dict | None = None) -> dict:
+    payload = {
+        "jsonrpc": "2.0",
+        "id": request_id,
+        "method": method,
+    }
+    if params is not None:
+        payload["params"] = params
+
+    request = urllib.request.Request(
+        f"http://{ip}/api/mcp",
+        data=json.dumps(payload).encode(),
+        headers={"Content-Type": "application/json"},
+        method="POST",
+    )
+    with urllib.request.urlopen(request, timeout=5) as response:
+        return json.loads(response.read())
+
+
+def require_result(response: dict, label: str) -> None:
+    if "error" in response:
+        raise RuntimeError(f"{label} failed: {response['error']}")
+    if "result" not in response:
+        raise RuntimeError(f"{label} returned no result: {response}")
+
+
+def make_bmp() -> bytes:
+    width = 4
+    height = 4
+    row_size = width * 3
+    pixels = bytearray()
+    colors = [
+        (0, 0, 255),
+        (0, 255, 0),
+        (255, 0, 0),
+        (255, 255, 255),
+    ]
+    for y in range(height):
+        for x in range(width):
+            blue, green, red = colors[(x + y) % len(colors)]
+            pixels.extend((blue, green, red))
+        pixels.extend(b"\0" * ((4 - row_size % 4) % 4))
+
+    offset = 54
+    file_size = offset + len(pixels)
+    header = (
+        b"BM"
+        + struct.pack("<IHHI", file_size, 0, 0, offset)
+        + struct.pack("<IIIHHIIIIII", 40, width, height, 1, 24, 0, len(pixels), 0, 0, 0, 0)
+    )
+    return header + pixels
+
+
+def raw_endpoint(ip: str) -> None:
+    pixels = bytes(
+        [
+            0xF8, 0x00,
+            0x07, 0xE0,
+            0x00, 0x1F,
+            0xFF, 0xFF,
+        ]
+    )
+    request = urllib.request.Request(
+        f"http://{ip}/api/screen/raw?x=2&y=2&w=2&h=2",
+        data=pixels,
+        headers={"Content-Type": "application/octet-stream"},
+        method="POST",
+    )
+    with urllib.request.urlopen(request, timeout=5) as response:
+        if response.read() != b"OK":
+            raise RuntimeError("Raw endpoint returned an unexpected response")
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--ip", help="Device IP; omit to use UDP discovery")
+    parser.add_argument(
+        "--draw",
+        action="store_true",
+        help="Also clear the app canvas and draw visible test text",
+    )
+    args = parser.parse_args()
+
+    ip = args.ip or discover()
+    if not ip:
+        raise SystemExit("MCP Screen was not discovered. Pass --ip DEVICE_IP to test directly.")
+
+    print(f"Testing MCP Screen at {ip}")
+
+    tools = rpc(ip, 1, "tools/list")
+    require_result(tools, "tools/list")
+    names = [tool["name"] for tool in tools["result"]["tools"]]
+    expected = {"get_capabilities", "clear_screen", "draw_text"}
+    if not expected.issubset(names):
+        raise RuntimeError(f"Missing tools: {sorted(expected - set(names))}")
+    print(f"tools/list: {', '.join(names)}")
+
+    capabilities = rpc(
+        ip,
+        2,
+        "tools/call",
+        {"name": "get_capabilities", "arguments": {}},
+    )
+    require_result(capabilities, "get_capabilities")
+    print("get_capabilities:", capabilities["result"]["content"][0]["text"])
+
+    if args.draw:
+        cleared = rpc(
+            ip,
+            3,
+            "tools/call",
+            {"name": "clear_screen", "arguments": {"color": 1}},
+        )
+        require_result(cleared, "clear_screen")
+
+        drawn = rpc(
+            ip,
+            4,
+            "tools/call",
+            {
+                "name": "draw_text",
+                "arguments": {
+                    "text": "Tactility MCP is alive",
+                    "x": 20,
+                    "y": 30,
+                    "size": 2,
+                },
+            },
+        )
+        require_result(drawn, "draw_text")
+
+        raw_rpc = rpc(
+            ip,
+            5,
+            "tools/call",
+            {
+                "name": "draw_raw_rgb565",
+                "arguments": {
+                    "rgb565_base64": base64.b64encode(
+                        bytes([0xFF, 0xE0, 0xF8, 0x1F, 0x07, 0xFF, 0x00, 0x00])
+                    ).decode(),
+                    "x": 20,
+                    "y": 70,
+                    "w": 4,
+                    "h": 1,
+                },
+            },
+        )
+        require_result(raw_rpc, "draw_raw_rgb565")
+
+        bmp = rpc(
+            ip,
+            6,
+            "tools/call",
+            {
+                "name": "draw_color_bmp",
+                "arguments": {
+                    "bmp_base64": base64.b64encode(make_bmp()).decode(),
+                    "x": 30,
+                    "y": 90,
+                },
+            },
+        )
+        require_result(bmp, "draw_color_bmp")
+
+        pbm_bytes = b"P4\n8 2\n" + bytes([0b10101010, 0b01010101])
+        pbm = rpc(
+            ip,
+            7,
+            "tools/call",
+            {
+                "name": "draw_image",
+                "arguments": {
+                    "pbm_base64": base64.b64encode(pbm_bytes).decode(),
+                    "x": 50,
+                    "y": 110,
+                },
+            },
+        )
+        require_result(pbm, "draw_image")
+
+        raw_endpoint(ip)
+
+        screenshot = rpc(
+            ip,
+            8,
+            "tools/call",
+            {"name": "get_screenshot", "arguments": {}},
+        )
+        require_result(screenshot, "get_screenshot")
+        screenshot_text = screenshot["result"]["content"][0]["text"]
+        if not screenshot_text.startswith("__PBM_BASE64__:"):
+            raise RuntimeError("Screenshot did not return PBM data")
+        base64.b64decode(screenshot_text.split(":", 1)[1], validate=True)
+        print("Visible Phase 2 draw and screenshot tests sent.")
+
+    print("Phase 2 smoke test passed.")
+
+
+if __name__ == "__main__":
+    main()

HowToCompile.md

@@ -0,0 +1,14 @@
+## 4. Workflow: Compiling & Installing Apps
+
+### Step 1: Source Environment & Path
+Ensure ESP-IDF environment is sourced and export local SDK path:
+```bash
+. /Users/adolforeyna/esp/esp-idf/export.sh
+export TACTILITY_SDK_PATH=/Users/adolforeyna/.gemini/antigravity/scratch/tactility/release/TactilitySDK
+```
+
+### Step 2: Compile the App
+Run the Tactility build script, specifying the target platform:
+```bash
+# Compile and package HelloWorld
+python3 tactility.py Apps/HelloWorld build esp32s3 --local-sdk