SDK sausage-actor; examples and agent on the SDK; agent without limits

- sausage-actor: Message, messages(), send/reply/publish, async Inbox
- agent: append-only /data/history.jsonl, no caps on history, steps, waits,
  tool output, or reads; max_tokens only when configured (Anthropic: 32000)

examples/notes-v2/Cargo.toml

@@ -4,4 +4,7 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
+sausage-actor = { version = "0.1", path = "../../sdk" }
 serde_json = "1"
+
+[workspace]

examples/notes-v2/src/main.rs

@@ -1,7 +1,5 @@
-//! Keeps a list of notes in /data/notes.json and publishes them as
-//! /public/notes.txt. Version 2: adds `count` and no longer crashes.
-use serde_json::{Value, json};
-use std::io::{BufRead, Write};
+//! Version 2 adds a note count and fixes the crash command.
+use sausage_actor::{json, messages, reply};
 
 const DATA: &str = "/data/notes.json";
 
@@ -13,27 +11,21 @@ fn save(notes: &[String]) {
 fn main() {
     let mut notes: Vec<String> = std::fs::read_to_string(DATA)
         .ok()
-        .and_then(|s| serde_json::from_str(&s).ok())
+        .and_then(|text| serde_json::from_str(&text).ok())
         .unwrap_or_default();
-    let mut out = std::io::stdout().lock();
-    for line in std::io::stdin().lock().lines() {
-        let Ok(line) = line else { break };
-        let Ok(msg) = serde_json::from_str::<Value>(&line) else { continue };
-        let body = &msg["body"];
-        let reply = match body["type"].as_str() {
-            Some("shutdown") => break,
-            Some("add") => {
+    for message in messages() {
+        let body = &message.body;
+        let response = match message.kind() {
+            "add" => {
                 notes.push(body["text"].as_str().unwrap_or_default().to_string());
                 save(&notes);
                 json!({"type": "added", "count": notes.len()})
             }
-            Some("list") => json!({"type": "notes", "items": notes}),
-            Some("count") => json!({"type": "count", "count": notes.len(), "version": 2}),
-            // Version 2 fixes the crash.
-            Some("crash") => json!({"type": "not_crashing", "version": 2}),
+            "list" => json!({"type": "notes", "items": notes}),
+            "count" => json!({"type": "count", "count": notes.len(), "version": 2}),
+            "crash" => json!({"type": "not_crashing", "version": 2}),
             _ => json!({"type": "error", "reason": "unknown message"}),
         };
-        writeln!(out, "{}", json!({"to": msg["from"], "reply_to": msg["id"], "body": reply})).unwrap();
-        out.flush().unwrap();
+        let _ = reply(&message, response);
     }
 }