GRACE Hello MCP
A very simple remote MCP server (Streamable HTTP transport) that advertises a
custom icon per the MCP spec (rev 2025-11-25, SEP-973), ready to deploy on
Render.
It exposes one tool, say_hello, and serves a custom PNG icon that is advertised
in the initialize response's serverInfo.icons.
Project layout
| File | Purpose |
|---|
server.js | The MCP server (Express + @modelcontextprotocol/sdk, Streamable HTTP). |
make_icon.py | Generates static/icon.png (stdlib only, no deps). Edit to change the icon. |
static/icon.png | The icon that gets advertised + served. |
render.yaml | Render blueprint for one-click deploy. |
Run locally
Quick smoke test:
curl -s -X POST http://localhost:3000/mcp \
-H 'Content-Type: application/json' \
-H 'Accept: application/json, text/event-stream' \
-d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-11-25","capabilities":{},"clientInfo":{"name":"curl","version":"0"}}}'
You should see serverInfo.icons in the response.
Or use the official MCP Inspector (renders the icon):
npx @modelcontextprotocol/inspector
Deploy on Render
- Push this folder to a GitHub repo.
- In Render: New ➜ Blueprint, point it at the repo. It reads
render.yaml
and creates a free Node web service. (Or New ➜ Web Service manually:
build npm install, start npm start.)
- Render injects
RENDER_EXTERNAL_URL automatically, so server.js builds the
correct absolute https://<your-service>.onrender.com/icon.png icon URL — no
manual env vars needed.
- Your MCP endpoint is
https://<your-service>.onrender.com/mcp.
Note: Render's free plan sleeps on idle, so the first request after a while
may take ~30s to wake.
Add it to an MCP client
Claude Code (CLI):
claude mcp add --transport http grace-hello https://<your-service>.onrender.com/mcp
Then in a session: /mcp to see it, and ask Claude to "use say_hello to greet Rajith".
Claude Desktop / other GUI clients: add a remote/HTTP MCP server pointing at
https://<your-service>.onrender.com/mcp.
About the icon (read this)
This server advertises its icon correctly per the MCP spec: the icons array
appears on serverInfo (and on the tool). It must be an https:// or data:
URI — we use the hosted https://.../icon.png.
Whether a client shows it is up to that client. Icon rendering is a newer,
inconsistently-supported feature:
- ✅ MCP Inspector and other spec-aware clients read and display it.
- ⚠️ Claude Code / Claude Desktop currently still show their default
placeholder for arbitrary third-party servers — the branded icons in Claude's
marketplace are first-party integrations configured on Anthropic's side. As
client icon support matures, this server is already compliant and will "just
work" with no changes.
Customize
- Icon: edit colors/shapes in
make_icon.py, then npm run make-icon
(regenerates static/icon.png). Or just drop your own 512×512 PNG at
static/icon.png.
- Tools: add more
setRequestHandler cases / tool definitions in server.js.