timezones

codex-rs/core/src/codex.rs

@@ -116,6 +116,7 @@ use crate::user_instructions::DeveloperInstructions;
 use crate::user_instructions::UserInstructions;
 use crate::user_notification::UserNotification;
 use crate::util::backoff;
+use chrono::Local;
 use codex_async_utils::OrCancelExt;
 use codex_otel::otel_event_manager::OtelEventManager;
 use codex_protocol::config_types::ReasoningEffort as ReasoningEffortConfig;
@@ -267,6 +268,7 @@ pub(crate) struct TurnContext {
     /// the model as well as sandbox policies are resolved against this path
     /// instead of `std::env::current_dir()`.
     pub(crate) cwd: PathBuf,
+    pub(crate) local_date_with_timezone: Option<String>,
     pub(crate) developer_instructions: Option<String>,
     pub(crate) base_instructions: Option<String>,
     pub(crate) compact_prompt: Option<String>,
@@ -423,6 +425,7 @@ impl Session {
             sub_id,
             client,
             cwd: session_configuration.cwd.clone(),
+            local_date_with_timezone: Some(Local::now().format("%Y-%m-%d %:z").to_string()),
             developer_instructions: session_configuration.developer_instructions.clone(),
             base_instructions: session_configuration.base_instructions.clone(),
             compact_prompt: session_configuration.compact_prompt.clone(),
@@ -1007,6 +1010,7 @@ impl Session {
         }
         items.push(ResponseItem::from(EnvironmentContext::new(
             Some(turn_context.cwd.clone()),
+            turn_context.local_date_with_timezone.clone(),
             Some(turn_context.approval_policy),
             Some(turn_context.sandbox_policy.clone()),
             Some(self.user_shell().clone()),
@@ -1692,6 +1696,7 @@ async fn spawn_review_thread(
         sandbox_policy: parent_turn_context.sandbox_policy.clone(),
         shell_environment_policy: parent_turn_context.shell_environment_policy.clone(),
         cwd: parent_turn_context.cwd.clone(),
+        local_date_with_timezone: parent_turn_context.local_date_with_timezone.clone(),
         final_output_json_schema: None,
         codex_linux_sandbox_exe: parent_turn_context.codex_linux_sandbox_exe.clone(),
         tool_call_gate: Arc::new(ReadinessFlag::new()),

codex-rs/core/src/environment_context.rs

@@ -24,6 +24,7 @@ pub enum NetworkAccess {
 #[serde(rename = "environment_context", rename_all = "snake_case")]
 pub(crate) struct EnvironmentContext {
     pub cwd: Option<PathBuf>,
+    pub local_date: Option<String>,
     pub approval_policy: Option<AskForApproval>,
     pub sandbox_mode: Option<SandboxMode>,
     pub network_access: Option<NetworkAccess>,
@@ -34,12 +35,14 @@ pub(crate) struct EnvironmentContext {
 impl EnvironmentContext {
     pub fn new(
         cwd: Option<PathBuf>,
+        local_date: Option<String>,
         approval_policy: Option<AskForApproval>,
         sandbox_policy: Option<SandboxPolicy>,
         shell: Option<Shell>,
     ) -> Self {
         Self {
             cwd,
+            local_date,
             approval_policy,
             sandbox_mode: match sandbox_policy {
                 Some(SandboxPolicy::DangerFullAccess) => Some(SandboxMode::DangerFullAccess),
@@ -79,6 +82,7 @@ impl EnvironmentContext {
     pub fn equals_except_shell(&self, other: &EnvironmentContext) -> bool {
         let EnvironmentContext {
             cwd,
+            local_date,
             approval_policy,
             sandbox_mode,
             network_access,
@@ -88,6 +92,7 @@ impl EnvironmentContext {
         } = other;
 
         self.cwd == *cwd
+            && self.local_date == *local_date
             && self.approval_policy == *approval_policy
             && self.sandbox_mode == *sandbox_mode
             && self.network_access == *network_access
@@ -100,6 +105,11 @@ impl EnvironmentContext {
         } else {
             None
         };
+        let local_date = if before.local_date_with_timezone != after.local_date_with_timezone {
+            after.local_date_with_timezone.clone()
+        } else {
+            None
+        };
         let approval_policy = if before.approval_policy != after.approval_policy {
             Some(after.approval_policy)
         } else {
@@ -110,7 +120,7 @@ impl EnvironmentContext {
         } else {
             None
         };
-        EnvironmentContext::new(cwd, approval_policy, sandbox_policy, None)
+        EnvironmentContext::new(cwd, local_date, approval_policy, sandbox_policy, None)
     }
 }
 
@@ -118,6 +128,7 @@ impl From<&TurnContext> for EnvironmentContext {
     fn from(turn_context: &TurnContext) -> Self {
         Self::new(
             Some(turn_context.cwd.clone()),
+            turn_context.local_date_with_timezone.clone(),
             Some(turn_context.approval_policy),
             Some(turn_context.sandbox_policy.clone()),
             // Shell is not configurable from turn to turn
@@ -134,6 +145,7 @@ impl EnvironmentContext {
     /// ```xml
     /// <environment_context>
     ///   <cwd>...</cwd>
+    ///   <local_date>...</local_date>
     ///   <approval_policy>...</approval_policy>
     ///   <sandbox_mode>...</sandbox_mode>
     ///   <writable_roots>...</writable_roots>
@@ -146,6 +158,9 @@ impl EnvironmentContext {
         if let Some(cwd) = self.cwd {
             lines.push(format!("  <cwd>{}</cwd>", cwd.to_string_lossy()));
         }
+        if let Some(local_date) = self.local_date {
+            lines.push(format!("  <local_date>{local_date}</local_date>"));
+        }
         if let Some(approval_policy) = self.approval_policy {
             lines.push(format!(
                 "  <approval_policy>{approval_policy}</approval_policy>"
@@ -212,6 +227,7 @@ mod tests {
     fn serialize_workspace_write_environment_context() {
         let context = EnvironmentContext::new(
             Some(PathBuf::from("/repo")),
+            Some("2025-01-01 +00:00".to_string()),
             Some(AskForApproval::OnRequest),
             Some(workspace_write_policy(vec!["/repo", "/tmp"], false)),
             None,
@@ -219,6 +235,7 @@ mod tests {
 
         let expected = r#"<environment_context>
   <cwd>/repo</cwd>
+  <local_date>2025-01-01 +00:00</local_date>
   <approval_policy>on-request</approval_policy>
   <sandbox_mode>workspace-write</sandbox_mode>
   <network_access>restricted</network_access>
@@ -235,12 +252,14 @@ mod tests {
     fn serialize_read_only_environment_context() {
         let context = EnvironmentContext::new(
             None,
+            Some("2025-01-01 +00:00".to_string()),
             Some(AskForApproval::Never),
             Some(SandboxPolicy::ReadOnly),
             None,
         );
 
         let expected = r#"<environment_context>
+  <local_date>2025-01-01 +00:00</local_date>
   <approval_policy>never</approval_policy>
   <sandbox_mode>read-only</sandbox_mode>
   <network_access>restricted</network_access>
@@ -253,12 +272,14 @@ mod tests {
     fn serialize_full_access_environment_context() {
         let context = EnvironmentContext::new(
             None,
+            Some("2025-01-01 +00:00".to_string()),
             Some(AskForApproval::OnFailure),
             Some(SandboxPolicy::DangerFullAccess),
             None,
         );
 
         let expected = r#"<environment_context>
+  <local_date>2025-01-01 +00:00</local_date>
   <approval_policy>on-failure</approval_policy>
   <sandbox_mode>danger-full-access</sandbox_mode>
   <network_access>enabled</network_access>
@@ -272,12 +293,14 @@ mod tests {
         // Approval policy
         let context1 = EnvironmentContext::new(
             Some(PathBuf::from("/repo")),
+            Some("2025-01-01 +00:00".to_string()),
             Some(AskForApproval::OnRequest),
             Some(workspace_write_policy(vec!["/repo"], false)),
             None,
         );
         let context2 = EnvironmentContext::new(
             Some(PathBuf::from("/repo")),
+            Some("2025-01-01 +00:00".to_string()),
             Some(AskForApproval::Never),
             Some(workspace_write_policy(vec!["/repo"], true)),
             None,
@@ -289,12 +312,14 @@ mod tests {
     fn equals_except_shell_compares_sandbox_policy() {
         let context1 = EnvironmentContext::new(
             Some(PathBuf::from("/repo")),
+            Some("2025-01-01 +00:00".to_string()),
             Some(AskForApproval::OnRequest),
             Some(SandboxPolicy::new_read_only_policy()),
             None,
         );
         let context2 = EnvironmentContext::new(
             Some(PathBuf::from("/repo")),
+            Some("2025-01-01 +00:00".to_string()),
             Some(AskForApproval::OnRequest),
             Some(SandboxPolicy::new_workspace_write_policy()),
             None,
@@ -307,12 +332,14 @@ mod tests {
     fn equals_except_shell_compares_workspace_write_policy() {
         let context1 = EnvironmentContext::new(
             Some(PathBuf::from("/repo")),
+            Some("2025-01-01 +00:00".to_string()),
             Some(AskForApproval::OnRequest),
             Some(workspace_write_policy(vec!["/repo", "/tmp", "/var"], false)),
             None,
         );
         let context2 = EnvironmentContext::new(
             Some(PathBuf::from("/repo")),
+            Some("2025-01-01 +00:00".to_string()),
             Some(AskForApproval::OnRequest),
             Some(workspace_write_policy(vec!["/repo", "/tmp"], true)),
             None,
@@ -325,6 +352,7 @@ mod tests {
     fn equals_except_shell_ignores_shell() {
         let context1 = EnvironmentContext::new(
             Some(PathBuf::from("/repo")),
+            Some("2025-01-01 +00:00".to_string()),
             Some(AskForApproval::OnRequest),
             Some(workspace_write_policy(vec!["/repo"], false)),
             Some(Shell::Bash(BashShell {
@@ -334,6 +362,7 @@ mod tests {
         );
         let context2 = EnvironmentContext::new(
             Some(PathBuf::from("/repo")),
+            Some("2025-01-01 +00:00".to_string()),
             Some(AskForApproval::OnRequest),
             Some(workspace_write_policy(vec!["/repo"], false)),
             Some(Shell::Zsh(ZshShell {

codex-rs/core/tests/suite/prompt_caching.rs

@@ -1,5 +1,6 @@
 #![allow(clippy::unwrap_used)]
 
+use chrono::Local;
 use codex_core::CodexAuth;
 use codex_core::ConversationManager;
 use codex_core::ModelProviderInfo;
@@ -40,9 +41,11 @@ fn text_user_input(text: String) -> serde_json::Value {
 }
 
 fn default_env_context_str(cwd: &str, shell: &Shell) -> String {
+    let local_date = Local::now().format("%Y-%m-%d %:z").to_string();
     format!(
         r#"<environment_context>
   <cwd>{}</cwd>
+  <local_date>{local_date}</local_date>
   <approval_policy>on-request</approval_policy>
   <sandbox_mode>read-only</sandbox_mode>
   <network_access>restricted</network_access>
@@ -344,19 +347,23 @@ async fn prefixes_context_and_instructions_once_and_consistently_across_requests
 
     let shell = default_user_shell().await;
 
-    let expected_env_text = format!(
+    let expected_env_text = {
-        r#"<environment_context>
+        let local_date = Local::now().format("%Y-%m-%d %:z").to_string();
+        format!(
+            r#"<environment_context>
   <cwd>{}</cwd>
+  <local_date>{local_date}</local_date>
   <approval_policy>on-request</approval_policy>
   <sandbox_mode>read-only</sandbox_mode>
   <network_access>restricted</network_access>
 {}</environment_context>"#,
-        cwd.path().to_string_lossy(),
+            cwd.path().to_string_lossy(),
-        match shell.name() {
+            match shell.name() {
-            Some(name) => format!("  <shell>{name}</shell>\n"),
+                Some(name) => format!("  <shell>{name}</shell>\n"),
-            None => String::new(),
+                None => String::new(),
-        }
+            }
-    );
+        )
+    };
     let expected_ui_text =
         "<user_instructions>\n\nbe consistent and helpful\n\n</user_instructions>";