Explain the SSL failure instead of just reporting it

A Postgres URL without an sslmode made lib/pq ask for TLS and die with
"SSL is not enabled on the server", which reads like a server fault when
it is really a connection-string default. The error now says what to
append, and the server retries briefly so a deploy is not marked
unhealthy just because Postgres was still starting.

The sync server URL also defaults to the hosted instance now, so a fresh
install needs no setup.

AGENTS.md

@@ -40,7 +40,10 @@ clicking an item copies it back to the clipboard.
   a global queue); only the store append hops back to main.
 - `Sources/Prompt/SyncService.swift` — optional sync client. Holds the group
   code and server URL in `UserDefaults` (`sync.code`, `sync.serverURL`,
-  `sync.version`), pushes the whole store as JSON, and polls every 5s.
+  `sync.version`). The URL defaults to `SyncService.defaultServerURL`
+  (`https://prompt.tzgyn.dev`); nothing is sent anywhere until a code exists,
+  because polling only runs when one is set. Pushes the whole store as JSON and
+  polls every 5s.
 - `Server/main.go` — the Go sync backend (single file, `net/http` + `lib/pq`).
   Also ships `Server/Dockerfile` (static binary on distroless) and
   `Server/README.md` (self-hosting). Logs one line per request, creates its

README.md

@@ -62,15 +62,16 @@ Or build the Docker image (`docker build -t prompt-sync Server/`) and point it
 at your own Postgres — see [Server/README.md](Server/README.md) for that and for
 deploying to a host.
 
-Then in the panel: click the sync icon, set the server URL (e.g.
-`http://192.168.1.10:8080` or an HTTPS host), and either **Generate Code** on
-the first Mac or paste the code into **Join** on the other.
+Then in the panel: click the sync icon (or Cmd+,), confirm the server URL, and
+either **Generate Code** on the first Mac or paste the code into **Join** on the
+other.
 
 Notes:
 
-- Both Macs must be able to reach the server. A LAN address or a Tailscale
-  hostname works; `localhost` only works if the server runs on the same Mac.
-  See [Server/README.md](Server/README.md) to deploy it on a VPS or home server.
+- Sync defaults to `https://prompt.tzgyn.dev`; change it in the sync panel to
+  point at your own server. Both Macs must be able to reach it — a LAN address
+  or a Tailscale hostname works, and `localhost` only works if the server runs
+  on the same Mac. See [Server/README.md](Server/README.md) to deploy it.
 - Joining a group that already has notes replaces what's on that Mac.
 - The app polls every 5 seconds (a tiny version check) and pushes 1.5s after a
   change; last write wins, and changes that came from the server are not echoed

Server/README.md

@@ -26,7 +26,31 @@ PROMPT_SYNC_DATABASE_URL="postgres://localhost:5432/prompt_sync?sslmode=disable"
 
 The schema is created on startup. Every request is logged as
 `METHOD PATH STATUS DURATION`; SIGTERM/SIGINT shut down gracefully so an
-in-flight push is not cut off mid-write.
+in-flight push is not cut off mid-write. If the database is not reachable yet
+it retries five times, 2s apart, before giving up.
+
+> **`sslmode` matters.** lib/pq defaults to `sslmode=require`, so a connection
+> string copied from a host that runs Postgres *without* TLS (Coolify's
+> internal Postgres, a plain `docker run postgres`, Homebrew) fails with
+> `pq: SSL is not enabled on the server`. Append `?sslmode=disable` in that
+> case — the server prints exactly that hint when it hits this.
+
+## Deploying with Coolify
+
+Use a Dockerfile application pointed at this repo with base directory `Server/`
+(so Coolify builds `Server/Dockerfile`), expose port `8080`, and set:
+
+| Variable | Value |
+| --- | --- |
+| `PROMPT_SYNC_DATABASE_URL` | your Postgres URL **plus `?sslmode=disable`** |
+| `PROMPT_SYNC_ADDR` | `:8080` (this is already the default) |
+
+Coolify detects the `HEALTHCHECK` in the Dockerfile and runs
+`prompt-sync -healthcheck` with its 5s start period, so the container only goes
+live once `/healthz` answers. It also logs a generic warning that a healthcheck
+needs `curl` or `wget` — that does not apply here, the binary does its own
+check, so there is no reason to add either to the image (it is distroless and
+has no shell).
 
 ## Run with Docker
 

Server/main.go

@@ -65,14 +65,11 @@ func main() {
 		addr = ":8080"
 	}
 
-	db, err := sql.Open("postgres", dsn)
+	db, err := openDatabase(dsn)
 	if err != nil {
-		log.Fatalf("open database: %v", err)
+		log.Fatalf("connect to database: %v%s", err, hintFor(err))
 	}
 	defer db.Close()
-	if err := db.Ping(); err != nil {
-		log.Fatalf("connect to database: %v", err)
-	}
 	if _, err := db.Exec(schema); err != nil {
 		log.Fatalf("ensure schema: %v", err)
 	}
@@ -111,6 +108,40 @@ func main() {
 	}
 }
 
+// openDatabase connects, retrying briefly so a deploy is not marked unhealthy
+// just because Postgres was still starting up.
+func openDatabase(dsn string) (*sql.DB, error) {
+	db, err := sql.Open("postgres", dsn)
+	if err != nil {
+		return nil, err
+	}
+	var lastErr error
+	for attempt := 1; attempt <= 5; attempt++ {
+		if lastErr = db.Ping(); lastErr == nil {
+			return db, nil
+		}
+		if attempt < 5 {
+			log.Printf("database not ready (attempt %d/5): %v", attempt, lastErr)
+			time.Sleep(2 * time.Second)
+		}
+	}
+	db.Close()
+	return nil, lastErr
+}
+
+// hintFor turns the most common connection failure into something actionable.
+// lib/pq defaults to sslmode=require, so any DSN copied from a host that runs
+// Postgres without TLS (Coolify's internal Postgres, docker-compose, Homebrew)
+// fails with a bare "SSL is not enabled on the server".
+func hintFor(err error) string {
+	if !strings.Contains(err.Error(), "SSL is not enabled") {
+		return ""
+	}
+	return "\n\nhint: lib/pq defaults to sslmode=require, but that Postgres has TLS off." +
+		"\n      Append ?sslmode=disable to PROMPT_SYNC_DATABASE_URL" +
+		"\n      (e.g. postgres://user:pass@host:5432/prompt_sync?sslmode=disable)."
+}
+
 // healthcheck returns 0 when the local /healthz answers 200.
 func healthcheck() int {
 	addr := os.Getenv("PROMPT_SYNC_ADDR")

Sources/Prompt/SyncService.swift

@@ -39,6 +39,9 @@ final class SyncService: ObservableObject {
     private static let urlKey = "sync.serverURL"
     private static let versionKey = "sync.version"
 
+    /// Where sync points unless the user overrides it in the sync panel.
+    static let defaultServerURL = "https://prompt.tzgyn.dev"
+
     private var lastVersion: Int64 {
         get { Int64(defaults.integer(forKey: Self.versionKey)) }
         set { defaults.set(newValue, forKey: Self.versionKey) }
@@ -54,7 +57,7 @@ final class SyncService: ObservableObject {
 
     private init() {
         code = defaults.string(forKey: Self.codeKey)
-        serverURL = defaults.string(forKey: Self.urlKey) ?? "http://localhost:8080"
+        serverURL = defaults.string(forKey: Self.urlKey) ?? Self.defaultServerURL
     }
 
     func start() {