Daemon

Source file: cmd/tachyond/main.go

The daemon entry point wires configuration, engine, and transport layers. It supports three modes: HTTP API server, MCP stdio server, and selftest.

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Design decisions

Flag-based mode selection

Three mutually exclusive modes, selected by flags:

./bin/tachyond              # HTTP API server (default)
./bin/tachyond --mcp        # MCP stdio server
./bin/tachyond --selftest   # MCP tool registry selftest, then exit

The --mcp flag redirects logs to stderr so stdout is reserved for NDJSON-RPC. The --selftest flag verifies tool registry consistency and exits with code 0 or 1.

Signal handling

The HTTP server runs in a goroutine; the main thread blocks on signal.Notify for SIGINT/SIGTERM. On signal, it initiates a graceful shutdown with a 10-second timeout.

sig := make(chan os.Signal, 1)
signal.Notify(sig, syscall.SIGINT, syscall.SIGTERM)
<-sig

ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
defer cancel()
srv.Shutdown(ctx)

Fatal error handling

Config load failures and engine init failures are fatal (os.Exit(1)). Server failures in the HTTP goroutine are also fatal. This is a daemon, not a library — crashing on misconfiguration is preferred over limping with undefined behavior.

No daemonization

The daemon does not fork, write PID files, or implement systemd notify. It is designed to run under a process supervisor (systemd, Docker, etc.) that handles these concerns.

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Startup flow

Parse flags (--mcp, --selftest)
    │
    ▼
Configure logger (stdout for HTTP, stderr for MCP/selftest)
    │
    ▼
Selftest? → verify tool registry → exit 0/1
    │
    ▼
Load config (tachyon.config.kvx + environment)
    │
    ▼
Initialize engine (registry, chains, compiler, tester, simulator, deployer, wallet)
    │
    ▼
MCP mode? → RunStdio(eng) → block on stdin
    │
    ▼
HTTP mode? → api.New(eng, logger) → ListenAndServe → block on signal

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Modifying the daemon