feat(managed-agents): Claude Code agent config isolation (B1–B8 + A1/A7 + Thufir invariants)

crates/buzz-acp/src/acp.rs

@@ -2108,6 +2108,27 @@ pub fn extract_model_state(result: &serde_json::Value) -> Option<serde_json::Val
     result.get("models").cloned()
 }
 
+/// B5: Extract the `configId` for the `thought_level` category option from a
+/// `session/new` result, if the adapter advertised one.
+///
+/// Claude Code's adapter uses `category: "thought_level"` in its configOptions.
+/// The configId is adapter-defined (e.g. `"effort"` on claude-agent-acp) and
+/// must not be hardcoded in the harness — this function discovers it at session
+/// time so `set_idle_agent_effort` can forward the real id.
+pub fn extract_thought_level_config_id(result: &serde_json::Value) -> Option<String> {
+    let arr = result["configOptions"].as_array()?;
+    for opt in arr {
+        if opt.get("category").and_then(|c| c.as_str()) == Some("thought_level") {
+            let config_id = opt
+                .get("configId")
+                .or_else(|| opt.get("id"))
+                .and_then(|v| v.as_str())?;
+            return Some(config_id.to_string());
+        }
+    }
+    None
+}
+
 /// Match a desired model ID against a fresh `session/new` response.
 ///
 /// Returns the correct ACP method to call, or `None` if no match.

crates/buzz-acp/src/config.rs

@@ -124,6 +124,11 @@ pub enum PermissionMode {
     /// Agent default — permission requests per tool call.
     #[value(alias = "default")]
     Default,
+    /// Auto mode — fully autonomous execution; model-gated (requires a model
+    /// that supports `supportsAutoMode`).  Degrades gracefully to `default`
+    /// when the session's active model does not support it.
+    #[value(alias = "auto")]
+    Auto,
     /// Auto-approve file edits, still ask for other tools.
     #[value(alias = "acceptEdits")]
     AcceptEdits,
@@ -144,6 +149,7 @@ impl PermissionMode {
     pub fn as_wire_str(&self) -> &'static str {
         match self {
             Self::Default => "default",
+            Self::Auto => "auto",
             Self::AcceptEdits => "acceptEdits",
             Self::BypassPermissions => "bypassPermissions",
             Self::DontAsk => "dontAsk",
@@ -2269,6 +2275,7 @@ channels = "ALL"
     #[test]
     fn test_permission_mode_wire_strings() {
         assert_eq!(PermissionMode::Default.as_wire_str(), "default");
+        assert_eq!(PermissionMode::Auto.as_wire_str(), "auto");
         assert_eq!(PermissionMode::AcceptEdits.as_wire_str(), "acceptEdits");
         assert_eq!(
             PermissionMode::BypassPermissions.as_wire_str(),
@@ -2281,19 +2288,32 @@ channels = "ALL"
     #[test]
     fn test_permission_mode_is_default() {
         assert!(PermissionMode::Default.is_default());
+        assert!(!PermissionMode::Auto.is_default());
         assert!(!PermissionMode::BypassPermissions.is_default());
         assert!(!PermissionMode::AcceptEdits.is_default());
         assert!(!PermissionMode::DontAsk.is_default());
         assert!(!PermissionMode::Plan.is_default());
     }
 
+    #[test]
+    fn test_permission_mode_auto_degrades_to_default_when_unsupported() {
+        // The wire string is "auto" — the adapter handles graceful downgrade
+        // to "default" when the active model does not support Auto mode.
+        // Verify only that the wire string is correct and distinct from "default".
+        let auto = PermissionMode::Auto;
+        assert_eq!(auto.as_wire_str(), "auto");
+        assert_ne!(auto.as_wire_str(), "default");
+        assert!(!auto.is_default());
+    }
+
     #[test]
     fn test_permission_mode_display() {
         assert_eq!(
             format!("{}", PermissionMode::BypassPermissions),
             "bypassPermissions"
         );
         assert_eq!(format!("{}", PermissionMode::Default), "default");
+        assert_eq!(format!("{}", PermissionMode::Auto), "auto");
     }
 
     #[test]