Make reasoning summary config fallback to model default

Keep config/session summary optional so missing values fall back to the model catalog default when building TurnContext, while TurnContext and request paths remain concrete. Also add protocol support for default_reasoning_summary with backward-compatible serde defaults.

Co-authored-by: Codex <noreply@openai.com>

codex-rs/Cargo.toml

@@ -118,8 +118,8 @@ codex-shell-command = { path = "shell-command" }
 codex-shell-escalation = { path = "shell-escalation" }
 codex-skills = { path = "skills" }
 codex-state = { path = "state" }
-codex-test-macros = { path = "test-macros" }
 codex-stdio-to-uds = { path = "stdio-to-uds" }
+codex-test-macros = { path = "test-macros" }
 codex-tui = { path = "tui" }
 codex-utils-absolute-path = { path = "utils/absolute-path" }
 codex-utils-approval-presets = { path = "utils/approval-presets" }
@@ -137,8 +137,8 @@ codex-utils-readiness = { path = "utils/readiness" }
 codex-utils-rustls-provider = { path = "utils/rustls-provider" }
 codex-utils-sandbox-summary = { path = "utils/sandbox-summary" }
 codex-utils-sleep-inhibitor = { path = "utils/sleep-inhibitor" }
-codex-utils-string = { path = "utils/string" }
 codex-utils-stream-parser = { path = "utils/stream-parser" }
+codex-utils-string = { path = "utils/string" }
 codex-windows-sandbox = { path = "windows-sandbox-rs" }
 core_test_support = { path = "core/tests/common" }
 mcp_test_support = { path = "mcp-server/tests/common" }
@@ -165,8 +165,8 @@ clap = "4"
 clap_complete = "4"
 color-eyre = "0.6.3"
 crossbeam-channel = "0.5.15"
-csv = "1.3.1"
 crossterm = "0.28.1"
+csv = "1.3.1"
 ctor = "0.6.3"
 derive_more = "2"
 diffy = "0.4.2"
@@ -178,8 +178,8 @@ env-flags = "0.1.1"
 env_logger = "0.11.9"
 eventsource-stream = "0.2.3"
 futures = { version = "0.3", default-features = false }
-globset = "0.4"
 gethostname = "1.1.0"
+globset = "0.4"
 http = "1.3.1"
 icu_decimal = "2.1"
 icu_locale_core = "2.1"
@@ -258,6 +258,7 @@ starlark = "0.13.0"
 strum = "0.27.2"
 strum_macros = "0.27.2"
 supports-color = "3.0.2"
+syntect = "5"
 sys-locale = "0.3.2"
 tempfile = "3.23.0"
 test-log = "0.2.19"
@@ -282,7 +283,6 @@ tracing-subscriber = "0.3.22"
 tracing-test = "0.2.5"
 tree-sitter = "0.25.10"
 tree-sitter-bash = "0.25"
-syntect = "5"
 ts-rs = "11"
 tungstenite = { version = "0.27.0", features = ["deflate", "proxy"] }
 uds_windows = "1.1.0"
@@ -352,6 +352,7 @@ ignored = [
 
 [profile.release]
 lto = "fat"
+split-debuginfo = "off"
 # Because we bundle some of these executables with the TypeScript CLI, we
 # remove everything to make the binary as small as possible.
 strip = "symbols"

codex-rs/core/src/codex.rs

@@ -754,7 +754,7 @@ pub(crate) struct SessionConfiguration {
     provider: ModelProviderInfo,
 
     collaboration_mode: CollaborationMode,
-    model_reasoning_summary: ReasoningSummaryConfig,
+    model_reasoning_summary: Option<ReasoningSummaryConfig>,
 
     /// Developer instructions that supplement the base instructions.
     developer_instructions: Option<String>,
@@ -824,7 +824,7 @@ impl SessionConfiguration {
             next_configuration.collaboration_mode = collaboration_mode;
         }
         if let Some(summary) = updates.reasoning_summary {
-            next_configuration.model_reasoning_summary = summary;
+            next_configuration.model_reasoning_summary = Some(summary);
         }
         if let Some(personality) = updates.personality {
             next_configuration.personality = Some(personality);
@@ -985,7 +985,9 @@ impl Session {
         skills_outcome: Arc<SkillLoadOutcome>,
     ) -> TurnContext {
         let reasoning_effort = session_configuration.collaboration_mode.reasoning_effort();
-        let reasoning_summary = session_configuration.model_reasoning_summary;
+        let reasoning_summary = session_configuration
+            .model_reasoning_summary
+            .unwrap_or(model_info.default_reasoning_summary);
         let otel_manager = otel_manager.clone().with_model(
             session_configuration.collaboration_mode.model(),
             model_info.slug.as_str(),
@@ -1262,7 +1264,7 @@ impl Session {
         otel_manager.conversation_starts(
             config.model_provider.name.as_str(),
             session_configuration.collaboration_mode.reasoning_effort(),
-            config.model_reasoning_summary,
+            config.model_reasoning_summary.unwrap_or(ReasoningSummaryConfig::Auto),
             config.model_context_window,
             config.model_auto_compact_token_limit,
             config.permissions.approval_policy.value(),
@@ -4615,7 +4617,9 @@ async fn spawn_review_thread(
     let provider_for_context = provider.clone();
     let otel_manager_for_context = otel_manager.clone();
     let reasoning_effort = per_turn_config.model_reasoning_effort;
-    let reasoning_summary = per_turn_config.model_reasoning_summary;
+    let reasoning_summary = per_turn_config
+        .model_reasoning_summary
+        .unwrap_or(model_info.default_reasoning_summary);
     let session_source = parent_turn_context.session_source.clone();
 
     let per_turn_config = Arc::new(per_turn_config);

codex-rs/core/src/config/mod.rs

@@ -412,9 +412,9 @@ pub struct Config {
     /// global default").
     pub plan_mode_reasoning_effort: Option<ReasoningEffort>,
 
-    /// If not "none", the value to use for `reasoning.summary` when making a
-    /// request using the Responses API.
-    pub model_reasoning_summary: ReasoningSummary,
+    /// Optional value to use for `reasoning.summary` when making a request
+    /// using the Responses API. When unset, the model catalog default is used.
+    pub model_reasoning_summary: Option<ReasoningSummary>,
 
     /// Optional override to force-enable reasoning summaries for the configured model.
     pub model_supports_reasoning_summaries: Option<bool>,
@@ -2141,8 +2141,7 @@ impl Config {
                 .or(cfg.plan_mode_reasoning_effort),
             model_reasoning_summary: config_profile
                 .model_reasoning_summary
-                .or(cfg.model_reasoning_summary)
-                .unwrap_or_default(),
+                .or(cfg.model_reasoning_summary),
             model_supports_reasoning_summaries: cfg.model_supports_reasoning_summaries,
             model_catalog,
             model_verbosity: config_profile.model_verbosity.or(cfg.model_verbosity),
@@ -4761,7 +4760,7 @@ model_verbosity = "high"
                 show_raw_agent_reasoning: false,
                 model_reasoning_effort: Some(ReasoningEffort::High),
                 plan_mode_reasoning_effort: None,
-                model_reasoning_summary: ReasoningSummary::Detailed,
+                model_reasoning_summary: Some(ReasoningSummary::Detailed),
                 model_supports_reasoning_summaries: None,
                 model_catalog: None,
                 model_verbosity: None,
@@ -4887,7 +4886,7 @@ model_verbosity = "high"
             show_raw_agent_reasoning: false,
             model_reasoning_effort: None,
             plan_mode_reasoning_effort: None,
-            model_reasoning_summary: ReasoningSummary::default(),
+            model_reasoning_summary: None,
             model_supports_reasoning_summaries: None,
             model_catalog: None,
             model_verbosity: None,
@@ -5011,7 +5010,7 @@ model_verbosity = "high"
             show_raw_agent_reasoning: false,
             model_reasoning_effort: None,
             plan_mode_reasoning_effort: None,
-            model_reasoning_summary: ReasoningSummary::default(),
+            model_reasoning_summary: None,
             model_supports_reasoning_summaries: None,
             model_catalog: None,
             model_verbosity: None,
@@ -5121,7 +5120,7 @@ model_verbosity = "high"
             show_raw_agent_reasoning: false,
             model_reasoning_effort: Some(ReasoningEffort::High),
             plan_mode_reasoning_effort: None,
-            model_reasoning_summary: ReasoningSummary::Detailed,
+            model_reasoning_summary: Some(ReasoningSummary::Detailed),
             model_supports_reasoning_summaries: None,
             model_catalog: None,
             model_verbosity: Some(Verbosity::High),

codex-rs/core/src/models_manager/model_info.rs

@@ -3,6 +3,7 @@ use codex_protocol::openai_models::ModelInfo;
 use codex_protocol::openai_models::ModelInstructionsVariables;
 use codex_protocol::openai_models::ModelMessages;
 use codex_protocol::openai_models::ModelVisibility;
+use codex_protocol::config_types::ReasoningSummary;
 use codex_protocol::openai_models::TruncationMode;
 use codex_protocol::openai_models::TruncationPolicyConfig;
 use codex_protocol::openai_models::default_input_modalities;
@@ -72,6 +73,7 @@ pub(crate) fn model_info_from_slug(slug: &str) -> ModelInfo {
         base_instructions: BASE_INSTRUCTIONS.to_string(),
         model_messages: local_personality_messages_for_slug(slug),
         supports_reasoning_summaries: false,
+        default_reasoning_summary: ReasoningSummary::Auto,
         support_verbosity: false,
         default_verbosity: None,
         apply_patch_tool_type: None,

codex-rs/core/src/tools/handlers/multi_agents.rs

@@ -914,7 +914,7 @@ fn build_agent_shared_config(turn: &TurnContext) -> Result<Config, FunctionCallE
     config.model = Some(turn.model_info.slug.clone());
     config.model_provider = turn.provider.clone();
     config.model_reasoning_effort = turn.reasoning_effort;
-    config.model_reasoning_summary = turn.reasoning_summary;
+    config.model_reasoning_summary = Some(turn.reasoning_summary);
     config.developer_instructions = turn.developer_instructions.clone();
     config.compact_prompt = turn.compact_prompt.clone();
     apply_spawn_agent_runtime_overrides(&mut config, turn)?;
@@ -2046,7 +2046,7 @@ mod tests {
         expected.model = Some(turn.model_info.slug.clone());
         expected.model_provider = turn.provider.clone();
         expected.model_reasoning_effort = turn.reasoning_effort;
-        expected.model_reasoning_summary = turn.reasoning_summary;
+        expected.model_reasoning_summary = Some(turn.reasoning_summary);
         expected.developer_instructions = turn.developer_instructions.clone();
         expected.compact_prompt = turn.compact_prompt.clone();
         expected.permissions.shell_environment_policy = turn.shell_environment_policy.clone();
@@ -2098,7 +2098,7 @@ mod tests {
         expected.model = Some(turn.model_info.slug.clone());
         expected.model_provider = turn.provider.clone();
         expected.model_reasoning_effort = turn.reasoning_effort;
-        expected.model_reasoning_summary = turn.reasoning_summary;
+        expected.model_reasoning_summary = Some(turn.reasoning_summary);
         expected.developer_instructions = turn.developer_instructions.clone();
         expected.compact_prompt = turn.compact_prompt.clone();
         expected.permissions.shell_environment_policy = turn.shell_environment_policy.clone();

codex-rs/protocol/src/openai_models.rs

@@ -15,6 +15,7 @@ use tracing::warn;
 use ts_rs::TS;
 
 use crate::config_types::Personality;
+use crate::config_types::ReasoningSummary;
 use crate::config_types::Verbosity;
 
 const PERSONALITY_PLACEHOLDER: &str = "{{ personality }}";
@@ -229,6 +230,8 @@ pub struct ModelInfo {
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub model_messages: Option<ModelMessages>,
     pub supports_reasoning_summaries: bool,
+    #[serde(default)]
+    pub default_reasoning_summary: ReasoningSummary,
     pub support_verbosity: bool,
     pub default_verbosity: Option<Verbosity>,
     pub apply_patch_tool_type: Option<ApplyPatchToolType>,
@@ -496,6 +499,7 @@ mod tests {
             base_instructions: "base".to_string(),
             model_messages: spec,
             supports_reasoning_summaries: false,
+            default_reasoning_summary: ReasoningSummary::Auto,
             support_verbosity: false,
             default_verbosity: None,
             apply_patch_tool_type: None,