tactility_apps/Apps/McpScreen/README.md

MCP Screen

Native Tactility port of the MicroPython MCP Screen firmware.

The current Phase 1 slice provides:

• JSON-RPC 2.0 over POST /api/mcp on port 80
• tools/list
• get_capabilities
• clear_screen
• draw_text

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 is explicitly stopped and deleted during onDestroy. This is required because Tactility unloads the external ELF after the app closes.

Build

. /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:

curl -s http://DEVICE_IP/api/mcp \
  -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}'

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:

python3 /Users/adolforeyna/Projects/MicroPython/test1/Screen/mcp_bridge.py

Or run the included Phase 1 smoke test:

python3 Apps/McpScreen/tools/smoke_test.py --ip DEVICE_IP --draw

The --ip argument is required until UDP discovery is available to external apps.