diff --git a/codex-rs/core/src/codex_tests.rs b/codex-rs/core/src/codex_tests.rs
index 6fe3055140..11864628de 100644
--- a/codex-rs/core/src/codex_tests.rs
+++ b/codex-rs/core/src/codex_tests.rs
@@ -8,6 +8,7 @@ use crate::config_loader::NetworkDomainPermissionToml;
 use crate::config_loader::NetworkDomainPermissionsToml;
 use crate::config_loader::RequirementSource;
 use crate::config_loader::Sourced;
+use crate::config_loader::project_trust_key;
 use crate::exec::ExecCapturePolicy;
 use crate::function_tool::FunctionCallError;
 use crate::shell::default_user_shell;
@@ -335,7 +336,7 @@ async fn write_project_trust_config(
                     .iter()
                     .map(|(project, trust_level)| {
                         (
-                            project.to_string_lossy().to_string(),
+                            project_trust_key(project),
                             ProjectConfig {
                                 trust_level: Some(*trust_level),
                             },
diff --git a/codex-rs/core/src/config/config_tests.rs b/codex-rs/core/src/config/config_tests.rs
index deba8a47b3..29dfdc9a34 100644
--- a/codex-rs/core/src/config/config_tests.rs
+++ b/codex-rs/core/src/config/config_tests.rs
@@ -2,6 +2,7 @@ use crate::config::edit::ConfigEdit;
 use crate::config::edit::ConfigEditsBuilder;
 use crate::config::edit::apply_blocking;
 use crate::config_loader::RequirementSource;
+use crate::config_loader::project_trust_key;
 use crate::plugins::PluginsManager;
 use assert_matches::assert_matches;
 use codex_config::CONFIG_TOML_FILE;
@@ -5110,7 +5111,9 @@ model = "foo""#;
 
     // Since we created the [projects] table as part of migration, it is kept implicit.
     // Expect explicit per-project tables, preserving prior entries and appending the new one.
-    let expected = r#"toplevel = "baz"
+    let new_project_key = project_trust_key(new_project);
+    let expected = format!(
+        r#"toplevel = "baz"
 model = "foo"
 
 [projects."/Users/mbolin/code/codex4"]
@@ -5120,9 +5123,10 @@ foo = "bar"
 [projects."/Users/mbolin/code/codex3"]
 trust_level = "trusted"
 
-[projects."/Users/mbolin/code/codex2"]
+[projects."{new_project_key}"]
 trust_level = "trusted"
-"#;
+"#
+    );
     assert_eq!(contents, expected);
 
     Ok(())