YAML configuration, init without a wizard, and openai-chat-completions

- /config/agent.yaml and /config/boot.yaml replace the JSON files, read
  with serde_yaml_ng (also in the agent, inside WASM).
- sausage init asks nothing and reads no SAUSAGE_* variables. It writes
  commented templates with an example for each API, and prints the path
  to edit. Until the agent is configured, agent.chat names the missing
  field. allow_no_token: true permits a local model without a key.
- The agent speaks openai-chat-completions, the format of OpenRouter,
  Ollama, and most providers. base_url follows each SDK: with /v1 for
  the OpenAI shapes, without it for Anthropic.
- Checked against the proxy with glm-5.3-flash: the agent wrote, built,
  and activated a counter plugin in 55 s.

cli/src/main.rs

@@ -3,18 +3,14 @@ use anyhow::{Result, bail};
 use clap::{Parser, Subcommand};
 use include_dir::{Dir, include_dir};
 use sausage::{Host, world::World};
-use serde_json::json;
-use std::{
-    io::Write,
-    path::{Path, PathBuf},
-};
+use std::path::{Path, PathBuf};
 
 static AGENT: Dir<'_> = include_dir!("$CARGO_MANIFEST_DIR/../agent/src");
 mod test_runner;
 #[derive(Parser)]
 #[command(version)]
 struct Cli {
-    #[arg(long, global = true, env = "SAUSAGE_HEADLESS", value_parser = headless)]
+    #[arg(long, global = true)]
     headless: bool,
     #[arg(long, global = true)]
     cache_dir: Option<PathBuf>,
@@ -60,33 +56,8 @@ impl Drop for TerminalMode {
     }
 }
 
-fn setting(var: &str, question: &str, default: Option<&str>) -> Result<String> {
-    if let Ok(v) = std::env::var(var)
-        && !v.is_empty()
-    {
-        return Ok(v);
-    }
-    print!("{question}: ");
-    std::io::stdout().flush()?;
-    let mut line = String::new();
-    std::io::stdin().read_line(&mut line)?;
-    if !line.trim().is_empty() {
-        return Ok(line.trim().into());
-    }
-    match default {
-        Some(v) => Ok(v.into()),
-        None => bail!("{question} is required"),
-    }
-}
-/// Creates a configured world and builds its embedded agent through the standalone builder.
+/// Creates a world with editable configuration and builds its embedded agent.
 async fn init(dir: &Path, cache: Option<&Path>) -> Result<()> {
-    let api = setting("SAUSAGE_API", "API shape", Some("openai-responses"))?;
-    if api != "openai-responses" && api != "anthropic-messages" {
-        bail!("unknown API shape {api:?}");
-    }
-    let base_url = setting("SAUSAGE_BASE_URL", "Base URL", None)?;
-    let model = setting("SAUSAGE_MODEL", "Model", None)?;
-    let token = setting("SAUSAGE_API_TOKEN", "API token", None)?;
     if dir.exists() {
         bail!("world already exists: {}", dir.display());
     }
@@ -100,10 +71,12 @@ async fn init(dir: &Path, cache: Option<&Path>) -> Result<()> {
         .tempdir_in(parent)?;
     let world = World::create(&staging.path().join("world"))?;
     std::fs::write(
-        world.root.join("config/agent.json"),
-        serde_json::to_vec_pretty(
-            &json!({"api":api,"base_url":base_url.trim_end_matches('/'),"model":model,"token":token}),
-        )?,
+        world.root.join("config/agent.yaml"),
+        include_str!("agent.yaml"),
+    )?;
+    std::fs::write(
+        world.root.join("config/boot.yaml"),
+        include_str!("boot.yaml"),
     )?;
     let cache = cache.map(Path::to_path_buf).unwrap_or_else(|| {
         let base = std::env::var_os("XDG_CACHE_HOME")
@@ -129,6 +102,10 @@ async fn init(dir: &Path, cache: Option<&Path>) -> Result<()> {
     let output = builder.build(&source).await?;
     std::fs::copy(output.wasm, world.plugin_dir("agent").join("plugin.wasm"))?;
     std::fs::rename(&world.root, dir)?;
+    println!(
+        "Edit {} before chatting.",
+        dir.join("config/agent.yaml").display()
+    );
     println!("Start the world with: sausage run {}", dir.display());
     Ok(())
 }
@@ -140,7 +117,7 @@ async fn main() -> Result<std::process::ExitCode> {
         Some(command) => command,
         None => {
             let dir = PathBuf::from("world");
-            if !dir.join("config/boot.json").is_file() {
+            if !dir.join("config/boot.yaml").is_file() {
                 init(&dir, cli.cache_dir.as_deref()).await?;
             }
             Cmd::Run { dir }
@@ -154,6 +131,12 @@ async fn main() -> Result<std::process::ExitCode> {
         }
         Cmd::Init { dir } => init(&dir, cli.cache_dir.as_deref()).await?,
         Cmd::Run { dir } => {
+            let headless = cli.headless
+                || std::env::var("SAUSAGE_HEADLESS")
+                    .ok()
+                    .map(|value| headless(&value).map_err(anyhow::Error::msg))
+                    .transpose()?
+                    .unwrap_or(false);
             let mut term =
                 tokio::signal::unix::signal(tokio::signal::unix::SignalKind::terminate())?;
             let mut interrupt =
@@ -170,7 +153,7 @@ async fn main() -> Result<std::process::ExitCode> {
                 _=interrupt.recv()=>return Ok(std::process::ExitCode::SUCCESS),
             };
             let mut notifications = host.subscribe();
-            let notification_task = cli.headless.then(|| {
+            let notification_task = headless.then(|| {
                 tokio::spawn(async move {
                     loop {
                         match notifications.recv().await {
@@ -186,8 +169,8 @@ async fn main() -> Result<std::process::ExitCode> {
             let exit = tokio::select! {
                 _=host.exit_requested()=>true,
                 _=term.recv()=>false,
-                _=interrupt.recv(), if cli.headless=>false,
-                result = console, if !cli.headless => {
+                _=interrupt.recv(), if headless=>false,
+                result = console, if !headless => {
                     console_result=result;
                     false
                 },