▶ Live Demo — click any tool button, no signup, no real accounts touched

An MCP (Model Context Protocol) server written in Rust, hand-rolled over JSON-RPC 2.0/stdio. It exposes 4 tools that call real external APIs (Render, Vercel, Buffer, Firestore, Gmail), plus the public HTTP demo above so anyone can try it from a browser without running an MCP client.

Tools

Tool	What it does
agency_pulse	Polls Render + Vercel and returns a rolled-up deployment status
content_check	Polls Buffer for scheduled posts across social profiles
data_vault	Queries a Firestore leads collection
send_gmail	Sends an email via Gmail SMTP (to, subject, body)

Each tool degrades gracefully when its API key isn't configured — it reports an empty/configuration_error state instead of crashing.

Two entry points, one shared implementation

• src/main.rs — the MCP server. JSON-RPC 2.0 over stdin/stdout, for real MCP clients (Claude Desktop/Code) with real credentials in .env.
• src/bin/web_server.rs — the public web demo. An Axum HTTP server exposing the same 4 tools as POST /api/*, plus a static page at /. Refuses to start unless DEMO_MODE=true — this binary has no auth, so it must never be able to reach real accounts.

Both call the same tool implementations in src/tools.rs — nothing is duplicated between them.

Demo Mode

Set DEMO_MODE=true and every tool returns realistic fixture data instead of calling a real account. send_gmail in demo mode simulates a send and never actually delivers mail. This is what the public deployment runs — no real credentials are set on that Render service at all.

Quick Start

# Build both binaries
cargo build --release

# Run the stdio MCP server (for a real MCP client, with real .env credentials)
cp .env.example .env   # fill in whichever keys you have
./target/release/agentic-rust-mcp

# Run the web demo locally
DEMO_MODE=true PORT=8080 ./target/release/web_server

MCP Protocol Usage

{"jsonrpc": "2.0", "id": 1, "method": "initialize", "params": {}}
{"jsonrpc": "2.0", "id": 2, "method": "tools/list", "params": {}}
{"jsonrpc": "2.0", "id": 3, "method": "tools/call", "params": {"name": "agency_pulse", "arguments": {}}}
{"jsonrpc": "2.0", "id": 4, "method": "tools/call", "params": {"name": "send_gmail", "arguments": {"to": "x@example.com", "subject": "hi", "body": "hello"}}}

Security

• Credentials load from .env (gitignored) via dotenv — nothing hardcoded.
• The public web demo can never reach real accounts: it hard-exits at startup unless DEMO_MODE=true, and no real keys are ever set on that deployment.
• No authentication layer exists on the web demo's API routes — it's read-only fixture data by design, not a production API surface.

Logging

Structured JSON logs via tracing:

RUST_LOG=info ./target/release/agentic-rust-mcp
RUST_LOG=debug ./target/release/agentic-rust-mcp

Architecture

   MCP client (stdio)         Browser (public demo)
          │                            │
          ▼                            ▼
   src/main.rs                 src/bin/web_server.rs
   (JSON-RPC 2.0)               (Axum, DEMO_MODE-gated)
          │                            │
          └──────────────┬─────────────┘
                          ▼
                    src/tools.rs
        (agency_pulse, content_check,
          data_vault, send_gmail)
                          │
        ┌────────┬────────┬────────┬────────┐
        ▼        ▼        ▼        ▼        ▼
    Render    Vercel    Buffer  Firestore  Gmail

Tech Stack

Layer	Technology
Runtime	tokio (async/await)
Web server	axum
Serialization	serde / serde_json
HTTP client	reqwest
Logging	tracing + tracing-subscriber
Config	dotenv
Email	lettre
Timestamps	chrono
Testing	built-in cargo test

License

MIT

Author

Chris Brown Albatross AI Portfolio