story-kit: merge 307_story_configurable_coder_pool_size_and_default_model_in_project_toml

server/src/config.rs

@@ -15,6 +15,17 @@ pub struct ProjectConfig {
     /// Per-story `qa` front matter overrides this. Default: "server".
     #[serde(default = "default_qa")]
     pub default_qa: String,
+    /// Default model for coder-stage agents (e.g. "sonnet").
+    /// When set, `find_free_agent_for_stage` only considers coder agents whose
+    /// model matches this value, so opus agents are only used when explicitly
+    /// requested via story front matter `agent:` field.
+    #[serde(default)]
+    pub default_coder_model: Option<String>,
+    /// Maximum number of concurrent coder-stage agents.
+    /// When set, `auto_assign_available_work` will not start more than this many
+    /// coder agents at once. Stories wait in `2_current/` until a slot frees up.
+    #[serde(default)]
+    pub max_coders: Option<usize>,
 }
 
 /// Configuration for the filesystem watcher's sweep behaviour.
@@ -134,6 +145,10 @@ struct LegacyProjectConfig {
     watcher: WatcherConfig,
     #[serde(default = "default_qa")]
     default_qa: String,
+    #[serde(default)]
+    default_coder_model: Option<String>,
+    #[serde(default)]
+    max_coders: Option<usize>,
 }
 
 impl Default for ProjectConfig {
@@ -156,6 +171,8 @@ impl Default for ProjectConfig {
             }],
             watcher: WatcherConfig::default(),
             default_qa: default_qa(),
+            default_coder_model: None,
+            max_coders: None,
         }
     }
 }
@@ -198,6 +215,8 @@ impl ProjectConfig {
                             agent: vec![agent],
                             watcher: legacy.watcher,
                             default_qa: legacy.default_qa,
+                            default_coder_model: legacy.default_coder_model,
+                            max_coders: legacy.max_coders,
                         };
                         validate_agents(&config.agent)?;
                         return Ok(config);
@@ -219,6 +238,8 @@ impl ProjectConfig {
                         agent: vec![agent],
                         watcher: legacy.watcher,
                         default_qa: legacy.default_qa,
+                        default_coder_model: legacy.default_coder_model,
+                        max_coders: legacy.max_coders,
                     };
                     validate_agents(&config.agent)?;
                     Ok(config)
@@ -228,6 +249,8 @@ impl ProjectConfig {
                         agent: Vec::new(),
                         watcher: legacy.watcher,
                         default_qa: legacy.default_qa,
+                        default_coder_model: legacy.default_coder_model,
+                        max_coders: legacy.max_coders,
                     })
                 }
             }
@@ -710,4 +733,68 @@ command = "claude"
         assert_eq!(config.watcher.done_retention_secs, 900);
         assert_eq!(config.agent.len(), 1);
     }
+
+    // ── default_coder_model & max_coders ─────────────────────────────────
+
+    #[test]
+    fn parse_default_coder_model_and_max_coders() {
+        let toml_str = r#"
+default_coder_model = "sonnet"
+max_coders = 3
+
+[[agent]]
+name = "coder-1"
+stage = "coder"
+model = "sonnet"
+
+[[agent]]
+name = "coder-opus"
+stage = "coder"
+model = "opus"
+"#;
+        let config = ProjectConfig::parse(toml_str).unwrap();
+        assert_eq!(config.default_coder_model, Some("sonnet".to_string()));
+        assert_eq!(config.max_coders, Some(3));
+    }
+
+    #[test]
+    fn default_coder_model_and_max_coders_default_to_none() {
+        let toml_str = r#"
+[[agent]]
+name = "coder-1"
+"#;
+        let config = ProjectConfig::parse(toml_str).unwrap();
+        assert_eq!(config.default_coder_model, None);
+        assert_eq!(config.max_coders, None);
+    }
+
+    #[test]
+    fn project_toml_has_default_coder_model_and_max_coders() {
+        // Verify the actual project.toml has the new settings.
+        let manifest_dir = std::path::Path::new(env!("CARGO_MANIFEST_DIR"));
+        let project_root = manifest_dir.parent().unwrap();
+        let config = ProjectConfig::load(project_root).unwrap();
+        assert_eq!(config.default_coder_model, Some("sonnet".to_string()));
+        assert_eq!(config.max_coders, Some(3));
+    }
+
+    #[test]
+    fn project_toml_has_three_sonnet_coders() {
+        let manifest_dir = std::path::Path::new(env!("CARGO_MANIFEST_DIR"));
+        let project_root = manifest_dir.parent().unwrap();
+        let config = ProjectConfig::load(project_root).unwrap();
+
+        let sonnet_coders: Vec<_> = config
+            .agent
+            .iter()
+            .filter(|a| a.stage.as_deref() == Some("coder") && a.model.as_deref() == Some("sonnet"))
+            .collect();
+
+        assert_eq!(
+            sonnet_coders.len(),
+            3,
+            "Expected 3 sonnet coders (coder-1, coder-2, coder-3), found {}",
+            sonnet_coders.len()
+        );
+    }
 }