huskies: merge 1015

server/src/agents/mod.rs

@@ -16,6 +16,10 @@ pub mod session_store;
 /// Token-usage tracking and budget estimation.
 pub mod token_usage;
 
+/// Typed agent model enum (Sonnet/Opus/Haiku).
+pub mod model;
+pub use model::AgentModel;
+
 use crate::config::AgentConfig;
 use serde::{Deserialize, Serialize};
 
@@ -205,13 +209,13 @@ impl TokenUsage {
     /// data in the agent log (since `total_cost_usd` is only available in the
     /// `result` event at session end).  Uses conservative (high) pricing when
     /// the model is unknown so budget limits are hit sooner rather than later.
-    pub fn estimate_cost_usd(&self, model: Option<&str>) -> f64 {
+    pub fn estimate_cost_usd(&self, model: Option<&AgentModel>) -> f64 {
         // Per-million-token pricing (input, output, cache_read, cache_create).
         let (inp, out, cr, cc) = match model {
-            Some(m) if m.contains("haiku") => (0.80, 4.0, 0.08, 1.00),
-            Some(m) if m.contains("sonnet") => (3.0, 15.0, 0.30, 3.75),
-            // Opus or unknown → most expensive = conservative.
-            _ => (15.0, 75.0, 1.50, 18.75),
+            Some(AgentModel::Haiku) => (0.80, 4.0, 0.08, 1.00),
+            Some(AgentModel::Sonnet) => (3.0, 15.0, 0.30, 3.75),
+            // Opus, Other, or unknown → most expensive = conservative.
+            Some(AgentModel::Opus) | Some(AgentModel::Other(_)) | None => (15.0, 75.0, 1.50, 18.75),
         };
         (self.input_tokens as f64 * inp
             + self.output_tokens as f64 * out

server/src/agents/model.rs

@@ -0,0 +1,125 @@
+//! Typed agent model — replaces raw model strings throughout the agent subsystem.
+use serde::{Deserialize, Deserializer, Serialize, Serializer};
+use std::fmt;
+
+/// Supported agent model families.
+///
+/// Serialises to the canonical short name ("sonnet", "opus", "haiku") or, for
+/// `Other`, the original string verbatim.  Deserialises from any string:
+/// Claude family names are matched by substring (e.g. "claude-sonnet-4-6"),
+/// everything else becomes `Other(string)` so non-Claude runtimes (Gemini,
+/// OpenAI, etc.) survive a config round-trip without error.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum AgentModel {
+    /// Claude Sonnet family.
+    Sonnet,
+    /// Claude Opus family.
+    Opus,
+    /// Claude Haiku family.
+    Haiku,
+    /// Any model string not recognised as a Claude family name.
+    Other(String),
+}
+
+impl AgentModel {
+    /// Canonical short name used for serialisation and CLI `--model` flags.
+    pub fn as_str(&self) -> &str {
+        match self {
+            Self::Sonnet => "sonnet",
+            Self::Opus => "opus",
+            Self::Haiku => "haiku",
+            Self::Other(s) => s.as_str(),
+        }
+    }
+
+    /// Parse any model string into a variant — always succeeds.
+    ///
+    /// Claude family names are matched by substring; everything else becomes
+    /// `Other`.
+    pub fn from_api_str(s: &str) -> Self {
+        if s.contains("haiku") {
+            Self::Haiku
+        } else if s.contains("sonnet") {
+            Self::Sonnet
+        } else if s.contains("opus") {
+            Self::Opus
+        } else {
+            Self::Other(s.to_string())
+        }
+    }
+}
+
+impl fmt::Display for AgentModel {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(self.as_str())
+    }
+}
+
+impl Serialize for AgentModel {
+    fn serialize<S: Serializer>(&self, s: S) -> Result<S::Ok, S::Error> {
+        s.serialize_str(self.as_str())
+    }
+}
+
+impl<'de> Deserialize<'de> for AgentModel {
+    fn deserialize<D: Deserializer<'de>>(d: D) -> Result<Self, D::Error> {
+        let s = String::deserialize(d)?;
+        Ok(Self::from_api_str(&s))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn short_names_deserialise() {
+        let s: AgentModel = serde_json::from_str("\"sonnet\"").unwrap();
+        assert_eq!(s, AgentModel::Sonnet);
+        let o: AgentModel = serde_json::from_str("\"opus\"").unwrap();
+        assert_eq!(o, AgentModel::Opus);
+        let h: AgentModel = serde_json::from_str("\"haiku\"").unwrap();
+        assert_eq!(h, AgentModel::Haiku);
+    }
+
+    #[test]
+    fn long_names_deserialise() {
+        let s: AgentModel = serde_json::from_str("\"claude-sonnet-4-6\"").unwrap();
+        assert_eq!(s, AgentModel::Sonnet);
+        let h: AgentModel = serde_json::from_str("\"claude-haiku-4-5-20251001\"").unwrap();
+        assert_eq!(h, AgentModel::Haiku);
+        let o: AgentModel = serde_json::from_str("\"claude-opus-4-5\"").unwrap();
+        assert_eq!(o, AgentModel::Opus);
+    }
+
+    #[test]
+    fn serialises_to_short_name() {
+        assert_eq!(
+            serde_json::to_string(&AgentModel::Sonnet).unwrap(),
+            "\"sonnet\""
+        );
+        assert_eq!(
+            serde_json::to_string(&AgentModel::Opus).unwrap(),
+            "\"opus\""
+        );
+        assert_eq!(
+            serde_json::to_string(&AgentModel::Haiku).unwrap(),
+            "\"haiku\""
+        );
+    }
+
+    #[test]
+    fn unknown_string_becomes_other() {
+        let r: AgentModel = serde_json::from_str("\"gemini-2.5-pro\"").unwrap();
+        assert_eq!(r, AgentModel::Other("gemini-2.5-pro".to_string()));
+        assert_eq!(r.as_str(), "gemini-2.5-pro");
+        // Round-trips verbatim
+        assert_eq!(serde_json::to_string(&r).unwrap(), "\"gemini-2.5-pro\"");
+    }
+
+    #[test]
+    fn option_none_round_trips() {
+        let v: Option<AgentModel> = serde_json::from_str("null").unwrap();
+        assert!(v.is_none());
+    }
+}

server/src/agents/pool/auto_assign/scan.rs

@@ -120,12 +120,10 @@ pub(in crate::agents::pool) fn find_free_agent_for_stage<'a>(
         // model matches. This keeps opus agents reserved for explicit requests.
         if *stage == PipelineStage::Coder
             && let Some(ref default_model) = config.default_coder_model
+            && agent_config.model.as_ref() != Some(default_model)
         {
-            let agent_model = agent_config.model.as_deref().unwrap_or("");
-            if agent_model != default_model {
             continue;
         }
-        }
         let is_busy = agents.values().any(|a| {
             a.agent_name == agent_config.name
                 && matches!(a.status, AgentStatus::Running | AgentStatus::Pending)

server/src/agents/pool/auto_assign/watchdog/budget.rs

@@ -67,7 +67,10 @@ pub(crate) fn compute_budget_from_single_log(path: &Path) -> f64 {
             && let Some(message) = data.get("message")
             && let Some(usage) = message.get("usage")
         {
-            let model = message.get("model").and_then(|v| v.as_str());
+            let model = message
+                .get("model")
+                .and_then(|v| v.as_str())
+                .map(crate::agents::AgentModel::from_api_str);
             let token_usage = TokenUsage {
                 input_tokens: usage
                     .get("input_tokens")
@@ -87,7 +90,7 @@ pub(crate) fn compute_budget_from_single_log(path: &Path) -> f64 {
                     .unwrap_or(0),
                 total_cost_usd: 0.0,
             };
-            cost += token_usage.estimate_cost_usd(model);
+            cost += token_usage.estimate_cost_usd(model.as_ref());
         }
     }
     cost

server/src/agents/pool/start/mod.rs

@@ -364,13 +364,13 @@ impl AgentPool {
         let effective_session_id = session_id_to_resume.or_else(|| {
             let model = config
                 .find_agent(&resolved_name)
-                .and_then(|a| a.model.clone())
-                .unwrap_or_default();
+                .and_then(|a| a.model.as_ref().map(|m| m.as_str()))
+                .unwrap_or("");
             crate::agents::session_store::lookup_session(
                 project_root,
                 story_id,
                 &resolved_name,
-                &model,
+                model,
             )
         });
 

server/src/agents/pool/start/spawn.rs

@@ -384,8 +384,7 @@ pub(super) async fn run_agent_spawn(
     // passed to RuntimeContext for eager session recording (bug 967).
     let agent_model = config_clone
         .find_agent(&aname)
-        .and_then(|a| a.model.clone())
-        .unwrap_or_default();
+        .and_then(|a| a.model.clone());
 
     let run_result = match runtime_name {
         "claude-code" => {
@@ -463,11 +462,15 @@ pub(super) async fn run_agent_spawn(
                 && let Some(agent) = agents.get(&key_clone)
                 && let Some(ref pr) = agent.project_root
             {
-                let model = config_clone
+                let model_for_record = config_clone
                     .find_agent(&aname)
                     .and_then(|a| a.model.clone());
-                let record =
-                    crate::agents::token_usage::build_record(&sid, &aname, model, usage.clone());
+                let record = crate::agents::token_usage::build_record(
+                    &sid,
+                    &aname,
+                    model_for_record,
+                    usage.clone(),
+                );
                 if let Err(e) = crate::agents::token_usage::append_record(pr, &record) {
                     slog_error!(
                         "[agents] Failed to persist token usage for \
@@ -480,13 +483,13 @@ pub(super) async fn run_agent_spawn(
             if let Some(ref sess_id) = result.session_id {
                 let model = config_clone
                     .find_agent(&aname)
-                    .and_then(|a| a.model.clone())
-                    .unwrap_or_default();
+                    .and_then(|a| a.model.as_ref().map(|m| m.as_str()))
+                    .unwrap_or("");
                 crate::agents::session_store::record_session(
                     &project_root_clone,
                     &sid,
                     &aname,
-                    &model,
+                    model,
                     sess_id,
                 );
             }

server/src/agents/runtime/claude_code.rs

@@ -42,11 +42,10 @@ impl AgentRuntime for ClaudeCodeRuntime {
         event_log: Arc<Mutex<Vec<AgentEvent>>>,
         log_writer: Option<Arc<Mutex<AgentLogWriter>>>,
     ) -> Result<RuntimeResult, String> {
-        let eager_record = if ctx.model.is_empty() {
-            None
-        } else {
-            Some((ctx.project_root.clone(), ctx.model.clone()))
-        };
+        let eager_record = ctx
+            .model
+            .as_ref()
+            .map(|m| (ctx.project_root.clone(), m.as_str().to_string()));
         let pty_result = super::super::pty::run_agent_pty_streaming(
             &ctx.story_id,
             &ctx.agent_name,

server/src/agents/runtime/gemini/api.rs

@@ -118,7 +118,7 @@ mod tests {
             session_id_to_resume: None,
             fresh_prompt: None,
             project_root: std::path::PathBuf::from("/tmp/project"),
-            model: String::new(),
+            model: None,
         };
 
         let instruction = build_system_instruction(&ctx);
@@ -139,7 +139,7 @@ mod tests {
             session_id_to_resume: None,
             fresh_prompt: None,
             project_root: std::path::PathBuf::from("/tmp/project"),
-            model: String::new(),
+            model: None,
         };
 
         let instruction = build_system_instruction(&ctx);

server/src/agents/runtime/gemini/mod.rs

@@ -385,7 +385,7 @@ mod tests {
             session_id_to_resume: None,
             fresh_prompt: None,
             project_root: std::path::PathBuf::from("/tmp/project"),
-            model: String::new(),
+            model: None,
         };
 
         // The model extraction logic is inside start(), but we test the

server/src/agents/runtime/mod.rs

@@ -46,9 +46,9 @@ pub struct RuntimeContext {
     /// Eager recording ensures the session survives a watchdog kill that aborts
     /// the tokio task before `run_agent_spawn`'s `record_session()` call runs.
     pub project_root: std::path::PathBuf,
-    /// Agent model name — forms part of the session store key used for eager
-    /// recording (bug 967).  An empty string disables eager recording.
-    pub model: String,
+    /// Agent model — forms part of the session store key used for eager
+    /// recording (bug 967).  `None` disables eager recording.
+    pub model: Option<crate::agents::AgentModel>,
 }
 
 /// Result returned by a runtime after the agent session completes.
@@ -134,7 +134,7 @@ mod tests {
             session_id_to_resume: None,
             fresh_prompt: None,
             project_root: std::path::PathBuf::from("/tmp/project"),
-            model: "sonnet".to_string(),
+            model: Some(crate::agents::AgentModel::Sonnet),
         };
         assert_eq!(ctx.story_id, "42_story_foo");
         assert_eq!(ctx.agent_name, "coder-1");

server/src/agents/runtime/openai.rs

@@ -561,7 +561,7 @@ mod tests {
             session_id_to_resume: None,
             fresh_prompt: None,
             project_root: std::path::PathBuf::from("/tmp/project"),
-            model: String::new(),
+            model: None,
         };
 
         assert_eq!(build_system_text(&ctx), "Custom system prompt");
@@ -581,7 +581,7 @@ mod tests {
             session_id_to_resume: None,
             fresh_prompt: None,
             project_root: std::path::PathBuf::from("/tmp/project"),
-            model: String::new(),
+            model: None,
         };
 
         let text = build_system_text(&ctx);
@@ -634,7 +634,7 @@ mod tests {
             session_id_to_resume: None,
             fresh_prompt: None,
             project_root: std::path::PathBuf::from("/tmp/project"),
-            model: String::new(),
+            model: None,
         };
         assert!(ctx.command.starts_with("gpt"));
     }
@@ -653,7 +653,7 @@ mod tests {
             session_id_to_resume: None,
             fresh_prompt: None,
             project_root: std::path::PathBuf::from("/tmp/project"),
-            model: String::new(),
+            model: None,
         };
         assert!(ctx.command.starts_with("o"));
     }

server/src/agents/token_usage.rs

@@ -5,7 +5,7 @@ use std::path::Path;
 use chrono::Utc;
 use serde::{Deserialize, Serialize};
 
-use super::TokenUsage;
+use super::{AgentModel, TokenUsage};
 
 /// A single token usage record persisted to disk.
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
@@ -14,7 +14,7 @@ pub struct TokenUsageRecord {
     pub agent_name: String,
     pub timestamp: String,
     #[serde(default)]
-    pub model: Option<String>,
+    pub model: Option<AgentModel>,
     pub usage: TokenUsage,
 }
 
@@ -75,7 +75,7 @@ pub fn read_all(project_root: &Path) -> Result<Vec<TokenUsageRecord>, String> {
 pub fn build_record(
     story_id: &str,
     agent_name: &str,
-    model: Option<String>,
+    model: Option<AgentModel>,
     usage: TokenUsage,
 ) -> TokenUsageRecord {
     TokenUsageRecord {

server/src/chat/commands/status/render.rs

@@ -340,7 +340,7 @@ fn render_item_line(
         let model_str = config
             .as_ref()
             .and_then(|cfg| cfg.find_agent(&agent.agent_name))
-            .and_then(|ac| ac.model.as_deref())
+            .and_then(|ac| ac.model.as_ref().map(|m| m.as_str()))
             .unwrap_or("?");
         format!(
             "  {dot}{display}{cost_suffix}{dep_suffix} — {} ({model_str})\n",

server/src/config/mod.rs

@@ -4,6 +4,7 @@
 pub mod agent_name;
 pub use agent_name::AgentName;
 
+use crate::agents::AgentModel;
 use crate::slog;
 use serde::Deserialize;
 use std::collections::HashSet;
@@ -22,12 +23,12 @@ 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").
+    /// 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>,
+    pub default_coder_model: Option<AgentModel>,
     /// 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.
@@ -240,7 +241,7 @@ pub struct AgentConfig {
     #[serde(default = "default_agent_prompt")]
     pub prompt: String,
     #[serde(default)]
-    pub model: Option<String>,
+    pub model: Option<AgentModel>,
     #[serde(default)]
     pub allowed_tools: Option<Vec<String>>,
     #[serde(default)]
@@ -312,7 +313,7 @@ struct LegacyProjectConfig {
     #[serde(default = "default_qa")]
     default_qa: String,
     #[serde(default)]
-    default_coder_model: Option<String>,
+    default_coder_model: Option<AgentModel>,
     #[serde(default)]
     max_coders: Option<usize>,
     #[serde(default = "default_max_retries")]
@@ -583,7 +584,7 @@ impl ProjectConfig {
         // Append structured CLI flags
         if let Some(ref model) = agent.model {
             args.push("--model".to_string());
-            args.push(model.clone());
+            args.push(model.as_str().to_string());
         }
         if let Some(ref tools) = agent.allowed_tools
             && !tools.is_empty()

server/src/config/tests.rs

@@ -39,7 +39,7 @@ max_budget_usd = 5.00
     assert_eq!(config.agent.len(), 2);
     assert_eq!(config.agent[0].name, "supervisor");
     assert_eq!(config.agent[0].role, "Coordinates work");
-    assert_eq!(config.agent[0].model, Some("opus".to_string()));
+    assert_eq!(config.agent[0].model, Some(crate::agents::AgentModel::Opus));
     assert_eq!(config.agent[0].max_turns, Some(50));
     assert_eq!(config.agent[0].max_budget_usd, Some(10.0));
     assert_eq!(
@@ -47,7 +47,10 @@ max_budget_usd = 5.00
         Some("You are a senior engineer".to_string())
     );
     assert_eq!(config.agent[1].name, "coder-1");
-    assert_eq!(config.agent[1].model, Some("sonnet".to_string()));
+    assert_eq!(
+        config.agent[1].model,
+        Some(crate::agents::AgentModel::Sonnet)
+    );
     assert_eq!(config.component.len(), 1);
 }
 
@@ -237,7 +240,10 @@ model = "sonnet"
     assert_eq!(config.component[1].setup, vec!["pnpm install"]);
     assert_eq!(config.agent.len(), 1);
     assert_eq!(config.agent[0].name, "main");
-    assert_eq!(config.agent[0].model, Some("sonnet".to_string()));
+    assert_eq!(
+        config.agent[0].model,
+        Some(crate::agents::AgentModel::Sonnet)
+    );
 }
 
 #[test]
@@ -269,7 +275,7 @@ model = "opus"
     let config = ProjectConfig::load(tmp.path()).unwrap();
     assert_eq!(config.agent.len(), 1);
     assert_eq!(config.agent[0].name, "from-agents-toml");
-    assert_eq!(config.agent[0].model, Some("opus".to_string()));
+    assert_eq!(config.agent[0].model, Some(crate::agents::AgentModel::Opus));
 }
 
 #[test]
@@ -438,7 +444,10 @@ stage = "coder"
 model = "opus"
 "#;
     let config = ProjectConfig::parse(toml_str).unwrap();
-    assert_eq!(config.default_coder_model, Some("sonnet".to_string()));
+    assert_eq!(
+        config.default_coder_model,
+        Some(crate::agents::AgentModel::Sonnet)
+    );
     assert_eq!(config.max_coders, Some(3));
 }
 
@@ -459,7 +468,10 @@ fn project_toml_has_default_coder_model_and_max_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();
-    assert_eq!(config.default_coder_model, Some("sonnet".to_string()));
+    assert_eq!(
+        config.default_coder_model,
+        Some(crate::agents::AgentModel::Sonnet)
+    );
     assert_eq!(config.max_coders, Some(3));
 }
 
@@ -617,7 +629,10 @@ fn project_toml_has_three_sonnet_coders() {
     let sonnet_coders: Vec<_> = config
         .agent
         .iter()
-        .filter(|a| a.stage.as_deref() == Some("coder") && a.model.as_deref() == Some("sonnet"))
+        .filter(|a| {
+            a.stage.as_deref() == Some("coder")
+                && a.model.as_ref() == Some(&crate::agents::AgentModel::Sonnet)
+        })
         .collect();
 
     assert_eq!(

server/src/crdt_sync/rpc.rs

@@ -694,7 +694,9 @@ async fn handle_settings_put_project(params: Value) -> Value {
     };
     let domain = crate::service::settings::ProjectSettings {
         default_qa: typed.default_qa,
-        default_coder_model: typed.default_coder_model,
+        default_coder_model: typed
+            .default_coder_model
+            .map(|s| crate::agents::AgentModel::from_api_str(&s)),
         max_coders: typed.max_coders,
         max_retries: typed.max_retries,
         base_branch: typed.base_branch,
@@ -713,7 +715,7 @@ async fn handle_settings_put_project(params: Value) -> Value {
     match crate::service::settings::load_project_settings(&root) {
         Ok(s) => serde_json::to_value(ProjectSettingsPayload {
             default_qa: s.default_qa,
-            default_coder_model: s.default_coder_model,
+            default_coder_model: s.default_coder_model.map(|m| m.as_str().to_string()),
             max_coders: s.max_coders,
             max_retries: s.max_retries,
             base_branch: s.base_branch,

server/src/http/workflow/pipeline.rs

@@ -10,7 +10,7 @@ use std::path::Path;
 #[derive(Clone, Debug, Serialize)]
 pub struct AgentAssignment {
     pub agent_name: crate::config::AgentName,
-    pub model: Option<String>,
+    pub model: Option<crate::agents::AgentModel>,
     pub status: crate::agents::AgentStatus,
 }
 

server/src/service/agents/mod.rs

@@ -68,7 +68,7 @@ pub struct AgentConfigEntry {
     pub name: String,
     pub role: String,
     pub stage: Option<String>,
-    pub model: Option<String>,
+    pub model: Option<crate::agents::AgentModel>,
     pub allowed_tools: Option<Vec<String>>,
     pub max_turns: Option<u32>,
     pub max_budget_usd: Option<f64>,
@@ -283,7 +283,7 @@ max_budget_usd = 5.0
         let entries = get_agent_config(tmp.path()).unwrap();
         assert_eq!(entries.len(), 1);
         assert_eq!(entries[0].name, "coder-1");
-        assert_eq!(entries[0].model, Some("sonnet".to_string()));
+        assert_eq!(entries[0].model, Some(crate::agents::AgentModel::Sonnet));
         assert_eq!(entries[0].max_turns, Some(30));
     }
 

server/src/service/agents/token.rs

@@ -9,7 +9,7 @@ use std::collections::HashMap;
 #[derive(Debug, Clone, PartialEq)]
 pub struct AgentTokenCost {
     pub agent_name: String,
-    pub model: Option<String>,
+    pub model: Option<crate::agents::AgentModel>,
     pub input_tokens: u64,
     pub output_tokens: u64,
     pub cache_creation_input_tokens: u64,
@@ -153,8 +153,11 @@ mod tests {
     #[test]
     fn aggregate_preserves_model_from_first_record() {
         let mut r = make_record("42_story_foo", "coder-1", 1.0);
-        r.model = Some("claude-sonnet".to_string());
+        r.model = Some(crate::agents::AgentModel::Sonnet);
         let summary = aggregate_for_story(&[r], "42_story_foo");
-        assert_eq!(summary.agents[0].model, Some("claude-sonnet".to_string()));
+        assert_eq!(
+            summary.agents[0].model,
+            Some(crate::agents::AgentModel::Sonnet)
+        );
     }
 }

server/src/service/settings/project.rs

@@ -5,6 +5,7 @@
 //! [`merge_settings_into_toml`] (the pure TOML key-updating logic used by the
 //! write path in `mod.rs` + `io.rs`).
 
+use crate::agents::AgentModel;
 use crate::config::ProjectConfig;
 use serde::{Deserialize, Serialize};
 
@@ -17,8 +18,8 @@ use serde::{Deserialize, Serialize};
 pub struct ProjectSettings {
     /// Project-wide default QA mode: "server", "agent", or "human". Default: "server".
     pub default_qa: String,
-    /// Default model for coder-stage agents (e.g. "sonnet").
-    pub default_coder_model: Option<String>,
+    /// Default model for coder-stage agents (e.g. `Sonnet`).
+    pub default_coder_model: Option<AgentModel>,
     /// Maximum number of concurrent coder-stage agents.
     pub max_coders: Option<u32>,
     /// Maximum retries per story per pipeline stage before marking as blocked. Default: 2.
@@ -89,7 +90,7 @@ pub fn merge_settings_into_toml(
         Some(v) => {
             table.insert(
                 "default_coder_model".to_string(),
-                toml::Value::String(v.clone()),
+                toml::Value::String(v.as_str().to_string()),
             );
         }
         None => {
@@ -180,7 +181,7 @@ mod tests {
     fn settings_from_config_copies_all_scalar_fields() {
         let cfg = ProjectConfig {
             default_qa: "human".to_string(),
-            default_coder_model: Some("opus".to_string()),
+            default_coder_model: Some(AgentModel::Opus),
             max_coders: Some(4),
             max_retries: 5,
             base_branch: Some("main".to_string()),
@@ -196,7 +197,7 @@ mod tests {
 
         let s = settings_from_config(&cfg);
         assert_eq!(s.default_qa, "human");
-        assert_eq!(s.default_coder_model, Some("opus".to_string()));
+        assert_eq!(s.default_coder_model, Some(AgentModel::Opus));
         assert_eq!(s.max_coders, Some(4));
         assert_eq!(s.max_retries, 5);
         assert_eq!(s.base_branch, Some("main".to_string()));
@@ -247,7 +248,7 @@ mod tests {
         let mut val = empty_toml();
         let s = ProjectSettings {
             default_qa: "server".to_string(),
-            default_coder_model: Some("sonnet".to_string()),
+            default_coder_model: Some(AgentModel::Sonnet),
             max_coders: Some(2),
             max_retries: 2,
             base_branch: Some("main".to_string()),
@@ -273,7 +274,7 @@ mod tests {
         // First set them
         let s_with = ProjectSettings {
             default_qa: "server".to_string(),
-            default_coder_model: Some("sonnet".to_string()),
+            default_coder_model: Some(AgentModel::Sonnet),
             max_coders: Some(3),
             max_retries: 2,
             base_branch: Some("master".to_string()),
@@ -372,7 +373,7 @@ path = "."
         let mut val = empty_toml();
         let s = ProjectSettings {
             default_qa: "human".to_string(),
-            default_coder_model: Some("opus".to_string()),
+            default_coder_model: Some(AgentModel::Opus),
             max_coders: Some(2),
             max_retries: 4,
             base_branch: Some("develop".to_string()),

server/src/service/settings/validate.rs

@@ -117,7 +117,7 @@ mod tests {
     fn valid_settings_with_all_optional_fields_set() {
         let s = ProjectSettings {
             default_qa: "agent".to_string(),
-            default_coder_model: Some("opus".to_string()),
+            default_coder_model: Some(crate::agents::AgentModel::Opus),
             max_coders: Some(4),
             max_retries: 5,
             base_branch: Some("main".to_string()),

server/src/service/ws/message/convert.rs

@@ -296,7 +296,7 @@ mod tests {
                 merge_failure: None,
                 agent: Some(crate::http::workflow::pipeline::AgentAssignment {
                     agent_name: crate::config::AgentName::Coder1,
-                    model: Some("claude-3-5-sonnet".to_string()),
+                    model: Some(crate::agents::AgentModel::Sonnet),
                     status: crate::agents::AgentStatus::Running,
                 }),
                 review_hold: None,
@@ -316,7 +316,7 @@ mod tests {
         let resp: WsResponse = state.into();
         let json = serde_json::to_value(&resp).unwrap();
         assert_eq!(json["current"][0]["agent"]["agent_name"], "coder-1");
-        assert_eq!(json["current"][0]["agent"]["model"], "claude-3-5-sonnet");
+        assert_eq!(json["current"][0]["agent"]["model"], "sonnet");
         assert_eq!(json["current"][0]["agent"]["status"], "running");
     }