Bind selected capability roots to model steps

codex-rs/exec-server/src/lib.rs

@@ -22,6 +22,7 @@ mod relay_proto;
 mod remote;
 mod remote_file_system;
 mod remote_process;
+mod resolved_capability;
 mod rpc;
 mod runtime_paths;
 mod sandboxed_file_system;
@@ -143,6 +144,7 @@ pub use protocol::WriteResponse;
 pub use protocol::WriteStatus;
 pub use remote::RemoteEnvironmentConfig;
 pub use remote::run_remote_environment;
+pub use resolved_capability::ResolvedSelectedCapabilityRoot;
 pub use runtime_paths::ExecServerRuntimePaths;
 pub use server::DEFAULT_LISTEN_URL;
 pub use server::ExecServerListenUrlParseError;

codex-rs/exec-server/src/resolved_capability.rs

@@ -0,0 +1,47 @@
+use std::fmt;
+use std::sync::Arc;
+
+use codex_protocol::capabilities::SelectedCapabilityRoot;
+
+use crate::Environment;
+use crate::ExecutorFileSystem;
+
+/// A selected capability root pinned to the exact environment instance that owns it.
+///
+/// This value is process-local and must not be persisted. Cloning it keeps the same
+/// [`Environment`] alive so every consumer of one model step uses the same executor.
+#[derive(Clone)]
+pub struct ResolvedSelectedCapabilityRoot {
+    selected_root: SelectedCapabilityRoot,
+    environment: Arc<Environment>,
+}
+
+impl ResolvedSelectedCapabilityRoot {
+    pub fn new(selected_root: SelectedCapabilityRoot, environment: Arc<Environment>) -> Self {
+        Self {
+            selected_root,
+            environment,
+        }
+    }
+
+    pub fn selected_root(&self) -> &SelectedCapabilityRoot {
+        &self.selected_root
+    }
+
+    pub fn environment(&self) -> &Arc<Environment> {
+        &self.environment
+    }
+
+    pub fn file_system(&self) -> Arc<dyn ExecutorFileSystem> {
+        self.environment.get_filesystem()
+    }
+}
+
+impl fmt::Debug for ResolvedSelectedCapabilityRoot {
+    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
+        formatter
+            .debug_struct("ResolvedSelectedCapabilityRoot")
+            .field("selected_root", &self.selected_root)
+            .finish_non_exhaustive()
+    }
+}