Remove reasoning format (#8484)

This isn't very useful parameter. 

logic:
```
if model puts `**` in their reasoning, trim it and visualize the header.
if couldn't trim: don't render
if model doesn't support: don't render
```

We can simplify to:
```
if could trim, visualize header.
if not, don't render
```

codex-rs/app-server/tests/common/models_cache.rs

@@ -5,7 +5,6 @@ use codex_protocol::openai_models::ConfigShellToolType;
 use codex_protocol::openai_models::ModelInfo;
 use codex_protocol::openai_models::ModelPreset;
 use codex_protocol::openai_models::ModelVisibility;
-use codex_protocol::openai_models::ReasoningSummaryFormat;
 use codex_protocol::openai_models::TruncationPolicyConfig;
 use serde_json::json;
 use std::path::Path;
@@ -35,7 +34,6 @@ fn preset_to_info(preset: &ModelPreset, priority: i32) -> ModelInfo {
         truncation_policy: TruncationPolicyConfig::bytes(10_000),
         supports_parallel_tool_calls: false,
         context_window: None,
-        reasoning_summary_format: ReasoningSummaryFormat::None,
         experimental_supported_tools: Vec::new(),
     }
 }

codex-rs/codex-api/src/endpoint/models.rs

@@ -227,7 +227,6 @@ mod tests {
                     "truncation_policy": {"mode": "bytes", "limit": 10_000},
                     "supports_parallel_tool_calls": false,
                     "context_window": null,
-                    "reasoning_summary_format": "none",
                     "experimental_supported_tools": [],
                 }))
                 .unwrap(),

codex-rs/codex-api/tests/models_integration.rs

@@ -10,7 +10,6 @@ use codex_protocol::openai_models::ModelVisibility;
 use codex_protocol::openai_models::ModelsResponse;
 use codex_protocol::openai_models::ReasoningEffort;
 use codex_protocol::openai_models::ReasoningEffortPreset;
-use codex_protocol::openai_models::ReasoningSummaryFormat;
 use codex_protocol::openai_models::TruncationPolicyConfig;
 use http::HeaderMap;
 use http::Method;
@@ -85,7 +84,6 @@ async fn models_client_hits_models_endpoint() {
             truncation_policy: TruncationPolicyConfig::bytes(10_000),
             supports_parallel_tool_calls: false,
             context_window: None,
-            reasoning_summary_format: ReasoningSummaryFormat::None,
             experimental_supported_tools: Vec::new(),
         }],
         etag: String::new(),

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

@@ -38,7 +38,6 @@ use codex_protocol::config_types::SandboxMode;
 use codex_protocol::config_types::TrustLevel;
 use codex_protocol::config_types::Verbosity;
 use codex_protocol::openai_models::ReasoningEffort;
-use codex_protocol::openai_models::ReasoningSummaryFormat;
 use codex_rmcp_client::OAuthCredentialsStoreMode;
 use codex_utils_absolute_path::AbsolutePathBuf;
 use codex_utils_absolute_path::AbsolutePathBufGuard;
@@ -303,9 +302,6 @@ pub struct Config {
     /// Optional override to force-enable reasoning summaries for the configured model.
     pub model_supports_reasoning_summaries: Option<bool>,
 
-    /// Optional override to force reasoning summary format for the configured model.
-    pub model_reasoning_summary_format: Option<ReasoningSummaryFormat>,
-
     /// Optional verbosity control for GPT-5 models (Responses API `text.verbosity`).
     pub model_verbosity: Option<Verbosity>,
 
@@ -786,9 +782,6 @@ pub struct ConfigToml {
     /// Override to force-enable reasoning summaries for the configured model.
     pub model_supports_reasoning_summaries: Option<bool>,
 
-    /// Override to force reasoning summary format for the configured model.
-    pub model_reasoning_summary_format: Option<ReasoningSummaryFormat>,
-
     /// Base URL for requests to ChatGPT (as opposed to the OpenAI API).
     pub chatgpt_base_url: Option<String>,
 
@@ -1379,7 +1372,6 @@ impl Config {
                 .or(cfg.model_reasoning_summary)
                 .unwrap_or_default(),
             model_supports_reasoning_summaries: cfg.model_supports_reasoning_summaries,
-            model_reasoning_summary_format: cfg.model_reasoning_summary_format.clone(),
             model_verbosity: config_profile.model_verbosity.or(cfg.model_verbosity),
             chatgpt_base_url: config_profile
                 .chatgpt_base_url
@@ -3189,7 +3181,6 @@ model_verbosity = "high"
                 model_reasoning_effort: Some(ReasoningEffort::High),
                 model_reasoning_summary: ReasoningSummary::Detailed,
                 model_supports_reasoning_summaries: None,
-                model_reasoning_summary_format: None,
                 model_verbosity: None,
                 chatgpt_base_url: "https://chatgpt.com/backend-api/".to_string(),
                 base_instructions: None,
@@ -3273,7 +3264,6 @@ model_verbosity = "high"
             model_reasoning_effort: None,
             model_reasoning_summary: ReasoningSummary::default(),
             model_supports_reasoning_summaries: None,
-            model_reasoning_summary_format: None,
             model_verbosity: None,
             chatgpt_base_url: "https://chatgpt.com/backend-api/".to_string(),
             base_instructions: None,
@@ -3372,7 +3362,6 @@ model_verbosity = "high"
             model_reasoning_effort: None,
             model_reasoning_summary: ReasoningSummary::default(),
             model_supports_reasoning_summaries: None,
-            model_reasoning_summary_format: None,
             model_verbosity: None,
             chatgpt_base_url: "https://chatgpt.com/backend-api/".to_string(),
             base_instructions: None,
@@ -3457,7 +3446,6 @@ model_verbosity = "high"
             model_reasoning_effort: Some(ReasoningEffort::High),
             model_reasoning_summary: ReasoningSummary::Detailed,
             model_supports_reasoning_summaries: None,
-            model_reasoning_summary_format: None,
             model_verbosity: Some(Verbosity::High),
             chatgpt_base_url: "https://chatgpt.com/backend-api/".to_string(),
             base_instructions: None,

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

@@ -354,7 +354,6 @@ mod tests {
             "truncation_policy": {"mode": "bytes", "limit": 10_000},
             "supports_parallel_tool_calls": false,
             "context_window": null,
-            "reasoning_summary_format": "none",
             "experimental_supported_tools": [],
         }))
         .expect("valid model")

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

@@ -3,7 +3,6 @@ use codex_protocol::openai_models::ApplyPatchToolType;
 use codex_protocol::openai_models::ConfigShellToolType;
 use codex_protocol::openai_models::ModelInfo;
 use codex_protocol::openai_models::ReasoningEffort;
-use codex_protocol::openai_models::ReasoningSummaryFormat;
 
 use crate::config::Config;
 use crate::truncate::TruncationPolicy;
@@ -48,9 +47,6 @@ pub struct ModelFamily {
     // The reasoning effort to use for this model family when none is explicitly chosen.
     pub default_reasoning_effort: Option<ReasoningEffort>,
 
-    // Define if we need a special handling of reasoning summary
-    pub reasoning_summary_format: ReasoningSummaryFormat,
-
     /// Whether this model supports parallel tool calls when using the
     /// Responses API.
     pub supports_parallel_tool_calls: bool,
@@ -88,9 +84,6 @@ impl ModelFamily {
         if let Some(supports_reasoning_summaries) = config.model_supports_reasoning_summaries {
             self.supports_reasoning_summaries = supports_reasoning_summaries;
         }
-        if let Some(reasoning_summary_format) = config.model_reasoning_summary_format.as_ref() {
-            self.reasoning_summary_format = reasoning_summary_format.clone();
-        }
         if let Some(context_window) = config.model_context_window {
             self.context_window = Some(context_window);
         }
@@ -128,7 +121,6 @@ impl ModelFamily {
             truncation_policy,
             supports_parallel_tool_calls,
             context_window,
-            reasoning_summary_format,
             experimental_supported_tools,
         } = model;
 
@@ -144,7 +136,6 @@ impl ModelFamily {
         self.truncation_policy = truncation_policy.into();
         self.supports_parallel_tool_calls = supports_parallel_tool_calls;
         self.context_window = context_window;
-        self.reasoning_summary_format = reasoning_summary_format;
         self.experimental_supported_tools = experimental_supported_tools;
     }
 
@@ -175,7 +166,6 @@ macro_rules! model_family {
             context_window: Some(CONTEXT_WINDOW_272K),
             auto_compact_token_limit: None,
             supports_reasoning_summaries: false,
-            reasoning_summary_format: ReasoningSummaryFormat::None,
             supports_parallel_tool_calls: false,
             apply_patch_tool_type: None,
             base_instructions: BASE_INSTRUCTIONS.to_string(),
@@ -250,7 +240,6 @@ pub(super) fn find_family_for_model(slug: &str) -> ModelFamily {
         model_family!(
             slug, slug,
             supports_reasoning_summaries: true,
-            reasoning_summary_format: ReasoningSummaryFormat::Experimental,
             base_instructions: GPT_5_CODEX_INSTRUCTIONS.to_string(),
             experimental_supported_tools: vec![
                 "grep_files".to_string(),
@@ -270,7 +259,6 @@ pub(super) fn find_family_for_model(slug: &str) -> ModelFamily {
         model_family!(
             slug, slug,
             supports_reasoning_summaries: true,
-            reasoning_summary_format: ReasoningSummaryFormat::Experimental,
             base_instructions: GPT_5_2_CODEX_INSTRUCTIONS.to_string(),
             apply_patch_tool_type: Some(ApplyPatchToolType::Freeform),
             shell_type: ConfigShellToolType::ShellCommand,
@@ -299,7 +287,6 @@ pub(super) fn find_family_for_model(slug: &str) -> ModelFamily {
         model_family!(
             slug, slug,
             supports_reasoning_summaries: true,
-            reasoning_summary_format: ReasoningSummaryFormat::Experimental,
             base_instructions: GPT_5_2_CODEX_INSTRUCTIONS.to_string(),
             apply_patch_tool_type: Some(ApplyPatchToolType::Freeform),
             shell_type: ConfigShellToolType::ShellCommand,
@@ -312,7 +299,6 @@ pub(super) fn find_family_for_model(slug: &str) -> ModelFamily {
         model_family!(
             slug, slug,
             supports_reasoning_summaries: true,
-            reasoning_summary_format: ReasoningSummaryFormat::Experimental,
             base_instructions: GPT_5_2_CODEX_INSTRUCTIONS.to_string(),
             apply_patch_tool_type: Some(ApplyPatchToolType::Freeform),
             shell_type: ConfigShellToolType::ShellCommand,
@@ -325,7 +311,6 @@ pub(super) fn find_family_for_model(slug: &str) -> ModelFamily {
         model_family!(
             slug, slug,
             supports_reasoning_summaries: true,
-            reasoning_summary_format: ReasoningSummaryFormat::Experimental,
             base_instructions: GPT_5_1_CODEX_MAX_INSTRUCTIONS.to_string(),
             apply_patch_tool_type: Some(ApplyPatchToolType::Freeform),
             shell_type: ConfigShellToolType::ShellCommand,
@@ -341,7 +326,6 @@ pub(super) fn find_family_for_model(slug: &str) -> ModelFamily {
         model_family!(
             slug, slug,
             supports_reasoning_summaries: true,
-            reasoning_summary_format: ReasoningSummaryFormat::Experimental,
             base_instructions: GPT_5_CODEX_INSTRUCTIONS.to_string(),
             apply_patch_tool_type: Some(ApplyPatchToolType::Freeform),
             shell_type: ConfigShellToolType::ShellCommand,
@@ -416,7 +400,6 @@ fn derive_default_model_family(model: &str) -> ModelFamily {
         context_window: None,
         auto_compact_token_limit: None,
         supports_reasoning_summaries: false,
-        reasoning_summary_format: ReasoningSummaryFormat::None,
         supports_parallel_tool_calls: false,
         apply_patch_tool_type: None,
         base_instructions: BASE_INSTRUCTIONS.to_string(),
@@ -460,7 +443,6 @@ mod tests {
             truncation_policy: TruncationPolicyConfig::bytes(10_000),
             supports_parallel_tool_calls: false,
             context_window: None,
-            reasoning_summary_format: ReasoningSummaryFormat::None,
             experimental_supported_tools: Vec::new(),
         }
     }
@@ -524,7 +506,6 @@ mod tests {
             experimental_supported_tools: vec!["local".to_string()],
             truncation_policy: TruncationPolicy::Bytes(10_000),
             context_window: Some(100),
-            reasoning_summary_format: ReasoningSummaryFormat::None,
         );
 
         let updated = family.with_remote_overrides(vec![ModelInfo {
@@ -549,7 +530,6 @@ mod tests {
             truncation_policy: TruncationPolicyConfig::tokens(2_000),
             supports_parallel_tool_calls: true,
             context_window: Some(400_000),
-            reasoning_summary_format: ReasoningSummaryFormat::Experimental,
             experimental_supported_tools: vec!["alpha".to_string(), "beta".to_string()],
         }]);
 
@@ -568,10 +548,6 @@ mod tests {
         assert_eq!(updated.truncation_policy, TruncationPolicy::Tokens(2_000));
         assert!(updated.supports_parallel_tool_calls);
         assert_eq!(updated.context_window, Some(400_000));
-        assert_eq!(
-            updated.reasoning_summary_format,
-            ReasoningSummaryFormat::Experimental
-        );
         assert_eq!(
             updated.experimental_supported_tools,
             vec!["alpha".to_string(), "beta".to_string()]

codex-rs/core/tests/responses_headers.rs

@@ -14,7 +14,6 @@ use codex_core::models_manager::manager::ModelsManager;
 use codex_otel::otel_manager::OtelManager;
 use codex_protocol::ConversationId;
 use codex_protocol::config_types::ReasoningSummary;
-use codex_protocol::openai_models::ReasoningSummaryFormat;
 use codex_protocol::protocol::SessionSource;
 use codex_protocol::protocol::SubAgentSource;
 use core_test_support::load_default_config_for_test;
@@ -246,7 +245,6 @@ async fn responses_respects_model_family_overrides_from_config() {
     config.model_provider_id = provider.name.clone();
     config.model_provider = provider.clone();
     config.model_supports_reasoning_summaries = Some(true);
-    config.model_reasoning_summary_format = Some(ReasoningSummaryFormat::Experimental);
     config.model_reasoning_summary = ReasoningSummary::Detailed;
     let effort = config.model_reasoning_effort;
     let summary = config.model_reasoning_summary;

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

@@ -24,7 +24,6 @@ use codex_protocol::openai_models::ModelVisibility;
 use codex_protocol::openai_models::ModelsResponse;
 use codex_protocol::openai_models::ReasoningEffort;
 use codex_protocol::openai_models::ReasoningEffortPreset;
-use codex_protocol::openai_models::ReasoningSummaryFormat;
 use codex_protocol::openai_models::TruncationPolicyConfig;
 use codex_protocol::user_input::UserInput;
 use core_test_support::load_default_config_for_test;
@@ -83,7 +82,6 @@ async fn remote_models_remote_model_uses_unified_exec() -> Result<()> {
         truncation_policy: TruncationPolicyConfig::bytes(10_000),
         supports_parallel_tool_calls: false,
         context_window: None,
-        reasoning_summary_format: ReasoningSummaryFormat::None,
         experimental_supported_tools: Vec::new(),
     };
 
@@ -222,7 +220,6 @@ async fn remote_models_apply_remote_base_instructions() -> Result<()> {
         truncation_policy: TruncationPolicyConfig::bytes(10_000),
         supports_parallel_tool_calls: false,
         context_window: None,
-        reasoning_summary_format: ReasoningSummaryFormat::None,
         experimental_supported_tools: Vec::new(),
     };
     mount_models_once(
@@ -486,7 +483,6 @@ fn test_remote_model(slug: &str, visibility: ModelVisibility, priority: i32) ->
         truncation_policy: TruncationPolicyConfig::bytes(10_000),
         supports_parallel_tool_calls: false,
         context_window: None,
-        reasoning_summary_format: ReasoningSummaryFormat::None,
         experimental_supported_tools: Vec::new(),
     }
 }

codex-rs/protocol/src/openai_models.rs

@@ -125,14 +125,6 @@ pub enum ApplyPatchToolType {
     Function,
 }
 
-#[derive(Deserialize, Debug, Clone, PartialEq, Eq, Default, Hash, TS, JsonSchema, Serialize)]
-#[serde(rename_all = "snake_case")]
-pub enum ReasoningSummaryFormat {
-    #[default]
-    None,
-    Experimental,
-}
-
 /// Server-provided truncation policy metadata for a model.
 #[derive(Debug, Serialize, Deserialize, Clone, Copy, PartialEq, Eq, TS, JsonSchema)]
 #[serde(rename_all = "snake_case")]
@@ -188,7 +180,6 @@ pub struct ModelInfo {
     pub truncation_policy: TruncationPolicyConfig,
     pub supports_parallel_tool_calls: bool,
     pub context_window: Option<i64>,
-    pub reasoning_summary_format: ReasoningSummaryFormat,
     pub experimental_supported_tools: Vec<String>,
 }
 

codex-rs/tui/src/chatwidget.rs

@@ -537,14 +537,11 @@ impl ChatWidget {
     }
 
     fn on_agent_reasoning_final(&mut self) {
-        let reasoning_summary_format = self.get_model_family().reasoning_summary_format;
         // At the end of a reasoning block, record transcript-only content.
         self.full_reasoning_buffer.push_str(&self.reasoning_buffer);
         if !self.full_reasoning_buffer.is_empty() {
-            let cell = history_cell::new_reasoning_summary_block(
+            let cell =
-                self.full_reasoning_buffer.clone(),
+                history_cell::new_reasoning_summary_block(self.full_reasoning_buffer.clone());
-                reasoning_summary_format,
-            );
             self.add_boxed_history(cell);
         }
         self.reasoning_buffer.clear();

codex-rs/tui/src/history_cell.rs

@@ -33,7 +33,6 @@ use codex_core::protocol::McpAuthStatus;
 use codex_core::protocol::McpInvocation;
 use codex_core::protocol::SessionConfiguredEvent;
 use codex_protocol::openai_models::ReasoningEffort as ReasoningEffortConfig;
-use codex_protocol::openai_models::ReasoningSummaryFormat;
 use codex_protocol::plan_tool::PlanItemArg;
 use codex_protocol::plan_tool::StepStatus;
 use codex_protocol::plan_tool::UpdatePlanArgs;
@@ -1661,39 +1660,28 @@ pub(crate) fn new_view_image_tool_call(path: PathBuf, cwd: &Path) -> PlainHistor
     PlainHistoryCell { lines }
 }
 
-pub(crate) fn new_reasoning_summary_block(
+pub(crate) fn new_reasoning_summary_block(full_reasoning_buffer: String) -> Box<dyn HistoryCell> {
-    full_reasoning_buffer: String,
+    let full_reasoning_buffer = full_reasoning_buffer.trim();
-    reasoning_summary_format: ReasoningSummaryFormat,
+    if let Some(open) = full_reasoning_buffer.find("**") {
-) -> Box<dyn HistoryCell> {
+        let after_open = &full_reasoning_buffer[(open + 2)..];
-    if reasoning_summary_format == ReasoningSummaryFormat::Experimental {
+        if let Some(close) = after_open.find("**") {
-        // Experimental format is following:
+            let after_close_idx = open + 2 + close + 2;
-        // ** header **
+            // if we don't have anything beyond `after_close_idx`
-        //
+            // then we don't have a summary to inject into history
-        // reasoning summary
+            if after_close_idx < full_reasoning_buffer.len() {
-        //
+                let header_buffer = full_reasoning_buffer[..after_close_idx].to_string();
-        // So we need to strip header from reasoning summary
+                let summary_buffer = full_reasoning_buffer[after_close_idx..].to_string();
-        let full_reasoning_buffer = full_reasoning_buffer.trim();
+                return Box::new(ReasoningSummaryCell::new(
-        if let Some(open) = full_reasoning_buffer.find("**") {
+                    header_buffer,
-            let after_open = &full_reasoning_buffer[(open + 2)..];
+                    summary_buffer,
-            if let Some(close) = after_open.find("**") {
+                    false,
-                let after_close_idx = open + 2 + close + 2;
+                ));
-                // if we don't have anything beyond `after_close_idx`
-                // then we don't have a summary to inject into history
-                if after_close_idx < full_reasoning_buffer.len() {
-                    let header_buffer = full_reasoning_buffer[..after_close_idx].to_string();
-                    let summary_buffer = full_reasoning_buffer[after_close_idx..].to_string();
-                    return Box::new(ReasoningSummaryCell::new(
-                        header_buffer,
-                        summary_buffer,
-                        false,
-                    ));
-                }
             }
         }
     }
     Box::new(ReasoningSummaryCell::new(
         "".to_string(),
-        full_reasoning_buffer,
+        full_reasoning_buffer.to_string(),
         true,
     ))
 }
@@ -1759,7 +1747,6 @@ mod tests {
     use codex_core::config::ConfigBuilder;
     use codex_core::config::types::McpServerConfig;
     use codex_core::config::types::McpServerTransportConfig;
-    use codex_core::models_manager::manager::ModelsManager;
     use codex_core::protocol::McpAuthStatus;
     use codex_protocol::parse_command::ParsedCommand;
     use dirs::home_dir;
@@ -2672,10 +2659,8 @@ mod tests {
     }
     #[test]
     fn reasoning_summary_block() {
-        let reasoning_format = ReasoningSummaryFormat::Experimental;
         let cell = new_reasoning_summary_block(
             "**High level reasoning**\n\nDetailed reasoning goes here.".to_string(),
-            reasoning_format,
         );
 
         let rendered_display = render_lines(&cell.display_lines(80));
@@ -2687,11 +2672,7 @@ mod tests {
 
     #[test]
     fn reasoning_summary_block_returns_reasoning_cell_when_feature_disabled() {
-        let reasoning_format = ReasoningSummaryFormat::Experimental;
+        let cell = new_reasoning_summary_block("Detailed reasoning goes here.".to_string());
-        let cell = new_reasoning_summary_block(
-            "Detailed reasoning goes here.".to_string(),
-            reasoning_format,
-        );
 
         let rendered = render_transcript(cell.as_ref());
         assert_eq!(rendered, vec!["• Detailed reasoning goes here."]);
@@ -2702,17 +2683,8 @@ mod tests {
         let mut config = test_config().await;
         config.model = Some("gpt-3.5-turbo".to_string());
         config.model_supports_reasoning_summaries = Some(true);
-        config.model_reasoning_summary_format = Some(ReasoningSummaryFormat::Experimental);
-        let model_family =
-            ModelsManager::construct_model_family_offline(&config.model.clone().unwrap(), &config);
-        assert_eq!(
-            model_family.reasoning_summary_format,
-            ReasoningSummaryFormat::Experimental
-        );
-
         let cell = new_reasoning_summary_block(
             "**High level reasoning**\n\nDetailed reasoning goes here.".to_string(),
-            model_family.reasoning_summary_format,
         );
 
         let rendered_display = render_lines(&cell.display_lines(80));
@@ -2721,11 +2693,8 @@ mod tests {
 
     #[test]
     fn reasoning_summary_block_falls_back_when_header_is_missing() {
-        let reasoning_format = ReasoningSummaryFormat::Experimental;
+        let cell =
-        let cell = new_reasoning_summary_block(
+            new_reasoning_summary_block("**High level reasoning without closing".to_string());
-            "**High level reasoning without closing".to_string(),
-            reasoning_format,
-        );
 
         let rendered = render_transcript(cell.as_ref());
         assert_eq!(rendered, vec!["• **High level reasoning without closing"]);
@@ -2733,18 +2702,14 @@ mod tests {
 
     #[test]
     fn reasoning_summary_block_falls_back_when_summary_is_missing() {
-        let reasoning_format = ReasoningSummaryFormat::Experimental;
+        let cell =
-        let cell = new_reasoning_summary_block(
+            new_reasoning_summary_block("**High level reasoning without closing**".to_string());
-            "**High level reasoning without closing**".to_string(),
-            reasoning_format.clone(),
-        );
 
         let rendered = render_transcript(cell.as_ref());
         assert_eq!(rendered, vec!["• High level reasoning without closing"]);
 
         let cell = new_reasoning_summary_block(
             "**High level reasoning without closing**\n\n  ".to_string(),
-            reasoning_format,
         );
 
         let rendered = render_transcript(cell.as_ref());
@@ -2753,10 +2718,8 @@ mod tests {
 
     #[test]
     fn reasoning_summary_block_splits_header_and_summary_when_present() {
-        let reasoning_format = ReasoningSummaryFormat::Experimental;
         let cell = new_reasoning_summary_block(
             "**High level plan**\n\nWe should fix the bug next.".to_string(),
-            reasoning_format,
         );
 
         let rendered_display = render_lines(&cell.display_lines(80));

codex-rs/tui2/src/chatwidget.rs

@@ -503,14 +503,11 @@ impl ChatWidget {
     }
 
     fn on_agent_reasoning_final(&mut self) {
-        let reasoning_summary_format = self.get_model_family().reasoning_summary_format;
         // At the end of a reasoning block, record transcript-only content.
         self.full_reasoning_buffer.push_str(&self.reasoning_buffer);
         if !self.full_reasoning_buffer.is_empty() {
-            let cell = history_cell::new_reasoning_summary_block(
+            let cell =
-                self.full_reasoning_buffer.clone(),
+                history_cell::new_reasoning_summary_block(self.full_reasoning_buffer.clone());
-                reasoning_summary_format,
-            );
             self.add_boxed_history(cell);
         }
         self.reasoning_buffer.clear();

codex-rs/tui2/src/history_cell.rs

@@ -29,7 +29,6 @@ use codex_core::protocol::McpAuthStatus;
 use codex_core::protocol::McpInvocation;
 use codex_core::protocol::SessionConfiguredEvent;
 use codex_protocol::openai_models::ReasoningEffort as ReasoningEffortConfig;
-use codex_protocol::openai_models::ReasoningSummaryFormat;
 use codex_protocol::plan_tool::PlanItemArg;
 use codex_protocol::plan_tool::StepStatus;
 use codex_protocol::plan_tool::UpdatePlanArgs;
@@ -1544,39 +1543,34 @@ pub(crate) fn new_view_image_tool_call(path: PathBuf, cwd: &Path) -> PlainHistor
     PlainHistoryCell { lines }
 }
 
-pub(crate) fn new_reasoning_summary_block(
+pub(crate) fn new_reasoning_summary_block(full_reasoning_buffer: String) -> Box<dyn HistoryCell> {
-    full_reasoning_buffer: String,
+    // Experimental format is following:
-    reasoning_summary_format: ReasoningSummaryFormat,
+    // ** header **
-) -> Box<dyn HistoryCell> {
+    //
-    if reasoning_summary_format == ReasoningSummaryFormat::Experimental {
+    // reasoning summary
-        // Experimental format is following:
+    //
-        // ** header **
+    // So we need to strip header from reasoning summary
-        //
+    let full_reasoning_buffer = full_reasoning_buffer.trim();
-        // reasoning summary
+    if let Some(open) = full_reasoning_buffer.find("**") {
-        //
+        let after_open = &full_reasoning_buffer[(open + 2)..];
-        // So we need to strip header from reasoning summary
+        if let Some(close) = after_open.find("**") {
-        let full_reasoning_buffer = full_reasoning_buffer.trim();
+            let after_close_idx = open + 2 + close + 2;
-        if let Some(open) = full_reasoning_buffer.find("**") {
+            // if we don't have anything beyond `after_close_idx`
-            let after_open = &full_reasoning_buffer[(open + 2)..];
+            // then we don't have a summary to inject into history
-            if let Some(close) = after_open.find("**") {
+            if after_close_idx < full_reasoning_buffer.len() {
-                let after_close_idx = open + 2 + close + 2;
+                let header_buffer = full_reasoning_buffer[..after_close_idx].to_string();
-                // if we don't have anything beyond `after_close_idx`
+                let summary_buffer = full_reasoning_buffer[after_close_idx..].to_string();
-                // then we don't have a summary to inject into history
+                return Box::new(ReasoningSummaryCell::new(
-                if after_close_idx < full_reasoning_buffer.len() {
+                    header_buffer,
-                    let header_buffer = full_reasoning_buffer[..after_close_idx].to_string();
+                    summary_buffer,
-                    let summary_buffer = full_reasoning_buffer[after_close_idx..].to_string();
+                    false,
-                    return Box::new(ReasoningSummaryCell::new(
+                ));
-                        header_buffer,
-                        summary_buffer,
-                        false,
-                    ));
-                }
             }
         }
     }
     Box::new(ReasoningSummaryCell::new(
         "".to_string(),
-        full_reasoning_buffer,
+        full_reasoning_buffer.to_string(),
         true,
     ))
 }
@@ -1642,7 +1636,6 @@ mod tests {
     use codex_core::config::ConfigBuilder;
     use codex_core::config::types::McpServerConfig;
     use codex_core::config::types::McpServerTransportConfig;
-    use codex_core::models_manager::manager::ModelsManager;
     use codex_core::protocol::McpAuthStatus;
     use codex_protocol::parse_command::ParsedCommand;
     use dirs::home_dir;
@@ -2489,10 +2482,8 @@ mod tests {
     }
     #[test]
     fn reasoning_summary_block() {
-        let reasoning_format = ReasoningSummaryFormat::Experimental;
         let cell = new_reasoning_summary_block(
             "**High level reasoning**\n\nDetailed reasoning goes here.".to_string(),
-            reasoning_format,
         );
 
         let rendered_display = render_lines(&cell.display_lines(80));
@@ -2504,11 +2495,7 @@ mod tests {
 
     #[test]
     fn reasoning_summary_block_returns_reasoning_cell_when_feature_disabled() {
-        let reasoning_format = ReasoningSummaryFormat::Experimental;
+        let cell = new_reasoning_summary_block("Detailed reasoning goes here.".to_string());
-        let cell = new_reasoning_summary_block(
-            "Detailed reasoning goes here.".to_string(),
-            reasoning_format,
-        );
 
         let rendered = render_transcript(cell.as_ref());
         assert_eq!(rendered, vec!["• Detailed reasoning goes here."]);
@@ -2519,17 +2506,9 @@ mod tests {
         let mut config = test_config().await;
         config.model = Some("gpt-3.5-turbo".to_string());
         config.model_supports_reasoning_summaries = Some(true);
-        config.model_reasoning_summary_format = Some(ReasoningSummaryFormat::Experimental);
-        let model_family =
-            ModelsManager::construct_model_family_offline(&config.model.clone().unwrap(), &config);
-        assert_eq!(
-            model_family.reasoning_summary_format,
-            ReasoningSummaryFormat::Experimental
-        );
 
         let cell = new_reasoning_summary_block(
             "**High level reasoning**\n\nDetailed reasoning goes here.".to_string(),
-            model_family.reasoning_summary_format,
         );
 
         let rendered_display = render_lines(&cell.display_lines(80));
@@ -2538,11 +2517,8 @@ mod tests {
 
     #[test]
     fn reasoning_summary_block_falls_back_when_header_is_missing() {
-        let reasoning_format = ReasoningSummaryFormat::Experimental;
+        let cell =
-        let cell = new_reasoning_summary_block(
+            new_reasoning_summary_block("**High level reasoning without closing".to_string());
-            "**High level reasoning without closing".to_string(),
-            reasoning_format,
-        );
 
         let rendered = render_transcript(cell.as_ref());
         assert_eq!(rendered, vec!["• **High level reasoning without closing"]);
@@ -2550,18 +2526,14 @@ mod tests {
 
     #[test]
     fn reasoning_summary_block_falls_back_when_summary_is_missing() {
-        let reasoning_format = ReasoningSummaryFormat::Experimental;
+        let cell =
-        let cell = new_reasoning_summary_block(
+            new_reasoning_summary_block("**High level reasoning without closing**".to_string());
-            "**High level reasoning without closing**".to_string(),
-            reasoning_format.clone(),
-        );
 
         let rendered = render_transcript(cell.as_ref());
         assert_eq!(rendered, vec!["• High level reasoning without closing"]);
 
         let cell = new_reasoning_summary_block(
             "**High level reasoning without closing**\n\n  ".to_string(),
-            reasoning_format,
         );
 
         let rendered = render_transcript(cell.as_ref());
@@ -2570,10 +2542,8 @@ mod tests {
 
     #[test]
     fn reasoning_summary_block_splits_header_and_summary_when_present() {
-        let reasoning_format = ReasoningSummaryFormat::Experimental;
         let cell = new_reasoning_summary_block(
             "**High level plan**\n\nWe should fix the bug next.".to_string(),
-            reasoning_format,
         );
 
         let rendered_display = render_lines(&cell.display_lines(80));

docs/config.md

@@ -1060,7 +1060,6 @@ Valid values:
 | `model_reasoning_summary`                        | `auto` \| `concise` \| `detailed` \| `none`                       | Reasoning summaries.                                                                                                            |
 | `model_verbosity`                                | `low` \| `medium` \| `high`                                       | GPT‑5 text verbosity (Responses API).                                                                                           |
 | `model_supports_reasoning_summaries`             | boolean                                                           | Force‑enable reasoning summaries.                                                                                               |
-| `model_reasoning_summary_format`                 | `none` \| `experimental`                                          | Force reasoning summary format.                                                                                                 |
 | `chatgpt_base_url`                               | string                                                            | Base URL for ChatGPT auth flow.                                                                                                 |
 | `experimental_instructions_file`                 | string (path)                                                     | Replace built‑in instructions (experimental).                                                                                   |
 | `experimental_use_exec_command_tool`             | boolean                                                           | Use experimental exec command tool.                                                                                             |

docs/example-config.md

@@ -49,9 +49,6 @@ model_verbosity = "medium"
 # Force-enable reasoning summaries for current model (default: false)
 model_supports_reasoning_summaries = false
 
-# Force reasoning summary format: none | experimental (default: none)
-model_reasoning_summary_format = "none"
-
 ################################################################################
 # Instruction Overrides
 ################################################################################