fix: switch rate limit reset handling to timestamps (#5304)

This change ensures that we store the absolute time instead of relative
offsets of when the primary and secondary rate limits will reset.
Previously these got recalculated relative to current time, which leads
to the displayed reset times to change over time, including after doing
a codex resume.

For previously changed sessions, this will cause the reset times to not
show due to this being a breaking change:
<img width="524" height="55" alt="Screenshot 2025-10-17 at 5 14 18 PM"
src="https://github.com/user-attachments/assets/53ebd43e-da25-4fef-9c47-94a529d40265"
/>

Fixes #4761

Author: tibo-openai

codex-rs/clippy.toml

@@ -7,3 +7,7 @@ disallowed-methods = [
     { path = "ratatui::style::Stylize::black", reason = "Avoid hardcoding black; prefer default fg or dim/bold. Exception: Disable this rule if rendering over a hardcoded ANSI background." },
     { path = "ratatui::style::Stylize::yellow", reason = "Avoid yellow; prefer other colors in `tui/styles.md`." },
 ]
+
+# Increase the size threshold for result_large_err to accommodate
+# richer error variants.
+large-error-threshold = 256

codex-rs/core/src/client.rs

@@ -52,6 +52,8 @@ use crate::protocol::TokenUsage;
 use crate::state::TaskKind;
 use crate::token_data::PlanType;
 use crate::util::backoff;
+use chrono::DateTime;
+use chrono::Utc;
 use codex_otel::otel_event_manager::OtelEventManager;
 use codex_protocol::config_types::ReasoningEffort as ReasoningEffortConfig;
 use codex_protocol::config_types::ReasoningSummary as ReasoningSummaryConfig;
@@ -71,7 +73,7 @@ struct Error {
 
     // Optional fields available on "usage_limit_reached" and "usage_not_included" errors
     plan_type: Option<PlanType>,
-    resets_in_seconds: Option<u64>,
+    resets_at: Option<String>,
 }
 
 #[derive(Debug, Clone)]
@@ -419,10 +421,14 @@ impl ModelClient {
                             let plan_type = error
                                 .plan_type
                                 .or_else(|| auth.as_ref().and_then(CodexAuth::get_plan_type));
-                            let resets_in_seconds = error.resets_in_seconds;
+                            let resets_at = error
+                                .resets_at
+                                .as_deref()
+                                .and_then(|value| DateTime::parse_from_rfc3339(value).ok())
+                                .map(|dt| dt.with_timezone(&Utc));
                             let codex_err = CodexErr::UsageLimitReached(UsageLimitReachedError {
                                 plan_type,
-                                resets_in_seconds,
+                                resets_at,
                                 rate_limits: rate_limit_snapshot,
                             });
                             return Err(StreamAttemptError::Fatal(codex_err));
@@ -605,14 +611,14 @@ fn parse_rate_limit_snapshot(headers: &HeaderMap) -> Option<RateLimitSnapshot> {
         headers,
         "x-codex-primary-used-percent",
         "x-codex-primary-window-minutes",
-        "x-codex-primary-reset-after-seconds",
+        "x-codex-primary-reset-at",
     );
 
     let secondary = parse_rate_limit_window(
         headers,
         "x-codex-secondary-used-percent",
         "x-codex-secondary-window-minutes",
-        "x-codex-secondary-reset-after-seconds",
+        "x-codex-secondary-reset-at",
     );
 
     Some(RateLimitSnapshot { primary, secondary })
@@ -628,16 +634,19 @@ fn parse_rate_limit_window(
 
     used_percent.and_then(|used_percent| {
         let window_minutes = parse_header_u64(headers, window_minutes_header);
-        let resets_in_seconds = parse_header_u64(headers, resets_header);
+        let resets_at = parse_header_str(headers, resets_header)
+            .map(str::trim)
+            .filter(|value| !value.is_empty())
+            .map(std::string::ToString::to_string);
 
         let has_data = used_percent != 0.0
             || window_minutes.is_some_and(|minutes| minutes != 0)
-            || resets_in_seconds.is_some_and(|seconds| seconds != 0);
+            || resets_at.is_some();
 
         has_data.then_some(RateLimitWindow {
             used_percent,
             window_minutes,
-            resets_in_seconds,
+            resets_at,
         })
     })
 }
@@ -1390,7 +1399,7 @@ mod tests {
             message: Some("Rate limit reached for gpt-5 in organization org- on tokens per min (TPM): Limit 1, Used 1, Requested 19304. Please try again in 28ms. Visit https://platform.openai.com/account/rate-limits to learn more.".to_string()),
             code: Some("rate_limit_exceeded".to_string()),
             plan_type: None,
-            resets_in_seconds: None
+            resets_at: None
         };
 
         let delay = try_parse_retry_after(&err);
@@ -1404,20 +1413,19 @@ mod tests {
             message: Some("Rate limit reached for gpt-5 in organization <ORG> on tokens per min (TPM): Limit 30000, Used 6899, Requested 24050. Please try again in 1.898s. Visit https://platform.openai.com/account/rate-limits to learn more.".to_string()),
             code: Some("rate_limit_exceeded".to_string()),
             plan_type: None,
-            resets_in_seconds: None
+            resets_at: None
         };
         let delay = try_parse_retry_after(&err);
         assert_eq!(delay, Some(Duration::from_secs_f64(1.898)));
     }
 
     #[test]
-    fn error_response_deserializes_old_schema_known_plan_type_and_serializes_back() {
+    fn error_response_deserializes_schema_known_plan_type_and_serializes_back() {
         use crate::token_data::KnownPlan;
         use crate::token_data::PlanType;
 
-        let json = r#"{"error":{"type":"usage_limit_reached","plan_type":"pro","resets_in_seconds":3600}}"#;
-        let resp: ErrorResponse =
-            serde_json::from_str(json).expect("should deserialize old schema");
+        let json = r#"{"error":{"type":"usage_limit_reached","plan_type":"pro","resets_at":"2024-01-01T00:00:00Z"}}"#;
+        let resp: ErrorResponse = serde_json::from_str(json).expect("should deserialize schema");
 
         assert_matches!(resp.error.plan_type, Some(PlanType::Known(KnownPlan::Pro)));
 
@@ -1426,13 +1434,11 @@ mod tests {
     }
 
     #[test]
-    fn error_response_deserializes_old_schema_unknown_plan_type_and_serializes_back() {
+    fn error_response_deserializes_schema_unknown_plan_type_and_serializes_back() {
         use crate::token_data::PlanType;
 
-        let json =
-            r#"{"error":{"type":"usage_limit_reached","plan_type":"vip","resets_in_seconds":60}}"#;
-        let resp: ErrorResponse =
-            serde_json::from_str(json).expect("should deserialize old schema");
+        let json = r#"{"error":{"type":"usage_limit_reached","plan_type":"vip","resets_at":"2024-01-01T00:01:00Z"}}"#;
+        let resp: ErrorResponse = serde_json::from_str(json).expect("should deserialize schema");
 
         assert_matches!(resp.error.plan_type, Some(PlanType::Unknown(ref s)) if s == "vip");