feat: add hide_agent_reasoning config option (#1181)

This PR introduces a `hide_agent_reasoning` config option (that defaults
to `false`) that users can enable to make the output less verbose by
suppressing reasoning output.

To test, verified that this includes agent reasoning in the output:

```
echo hello | just exec
```

whereas this does not:

```
echo hello | just exec --config hide_agent_reasoning=false
```

codex-rs/config.md

@@ -354,6 +354,16 @@ Note this is **not** a general editor setting (like `$EDITOR`), as it only accep
 
 Currently, `"vscode"` is the default, though Codex does not verify VS Code is installed. As such, `file_opener` may default to `"none"` or something else in the future.
 
+## hide_agent_reasoning
+
+Codex intermittently emits "reasoning" events that show the model’s internal "thinking" before it produces a final answer. Some users may find these events distracting, especially in CI logs or minimal terminal output.
+
+Setting `hide_agent_reasoning` to `true` suppresses these events in **both** the TUI as well as the headless `exec` sub-command:
+
+```toml
+hide_agent_reasoning = true   # defaults to false
+```
+
 ## project_doc_max_bytes
 
 Maximum number of bytes to read from an `AGENTS.md` file to include in the instructions sent with the first turn of a session. Defaults to 32 KiB.

codex-rs/core/src/config.rs

@@ -42,6 +42,11 @@ pub struct Config {
 
     pub shell_environment_policy: ShellEnvironmentPolicy,
 
+    /// When `true`, `AgentReasoning` events emitted by the backend will be
+    /// suppressed from the frontend output. This can reduce visual noise when
+    /// users are only interested in the final agent responses.
+    pub hide_agent_reasoning: bool,
+
     /// Disable server-side response storage (sends the full conversation
     /// context with every request). Currently necessary for OpenAI customers
     /// who have opted into Zero Data Retention (ZDR).
@@ -272,6 +277,10 @@ pub struct ConfigToml {
 
     /// Collection of settings that are specific to the TUI.
     pub tui: Option<Tui>,
+
+    /// When set to `true`, `AgentReasoning` events will be hidden from the
+    /// UI/output. Defaults to `false`.
+    pub hide_agent_reasoning: Option<bool>,
 }
 
 fn deserialize_sandbox_permissions<'de, D>(
@@ -433,6 +442,8 @@ impl Config {
             file_opener: cfg.file_opener.unwrap_or(UriBasedFileOpener::VsCode),
             tui: cfg.tui.unwrap_or_default(),
             codex_linux_sandbox_exe,
+
+            hide_agent_reasoning: cfg.hide_agent_reasoning.unwrap_or(false),
         };
         Ok(config)
     }
@@ -774,6 +785,7 @@ disable_response_storage = true
                 file_opener: UriBasedFileOpener::VsCode,
                 tui: Tui::default(),
                 codex_linux_sandbox_exe: None,
+                hide_agent_reasoning: false,
             },
             o3_profile_config
         );
@@ -813,6 +825,7 @@ disable_response_storage = true
             file_opener: UriBasedFileOpener::VsCode,
             tui: Tui::default(),
             codex_linux_sandbox_exe: None,
+            hide_agent_reasoning: false,
         };
 
         assert_eq!(expected_gpt3_profile_config, gpt3_profile_config);
@@ -867,6 +880,7 @@ disable_response_storage = true
             file_opener: UriBasedFileOpener::VsCode,
             tui: Tui::default(),
             codex_linux_sandbox_exe: None,
+            hide_agent_reasoning: false,
         };
 
         assert_eq!(expected_zdr_profile_config, zdr_profile_config);

codex-rs/exec/src/event_processor.rs

@@ -43,10 +43,13 @@ pub(crate) struct EventProcessor {
     red: Style,
     green: Style,
     cyan: Style,
+
+    /// Whether to include `AgentReasoning` events in the output.
+    show_agent_reasoning: bool,
 }
 
 impl EventProcessor {
-    pub(crate) fn create_with_ansi(with_ansi: bool) -> Self {
+    pub(crate) fn create_with_ansi(with_ansi: bool, show_agent_reasoning: bool) -> Self {
         let call_id_to_command = HashMap::new();
         let call_id_to_patch = HashMap::new();
         let call_id_to_tool_call = HashMap::new();
@@ -63,6 +66,7 @@ impl EventProcessor {
                 green: Style::new().green(),
                 cyan: Style::new().cyan(),
                 call_id_to_tool_call,
+                show_agent_reasoning,
             }
         } else {
             Self {
@@ -76,6 +80,7 @@ impl EventProcessor {
                 green: Style::new(),
                 cyan: Style::new(),
                 call_id_to_tool_call,
+                show_agent_reasoning,
             }
         }
     }
@@ -411,12 +416,14 @@ impl EventProcessor {
                 // Should we exit?
             }
             EventMsg::AgentReasoning(agent_reasoning_event) => {
-                ts_println!(
-                    self,
-                    "{}\n{}",
-                    "thinking".style(self.italic).style(self.magenta),
-                    agent_reasoning_event.text
-                );
+                if self.show_agent_reasoning {
+                    ts_println!(
+                        self,
+                        "{}\n{}",
+                        "thinking".style(self.italic).style(self.magenta),
+                        agent_reasoning_event.text
+                    );
+                }
             }
             EventMsg::SessionConfigured(session_configured_event) => {
                 let SessionConfiguredEvent {

codex-rs/exec/src/lib.rs

@@ -112,7 +112,8 @@ pub async fn run_main(cli: Cli, codex_linux_sandbox_exe: Option<PathBuf>) -> any
     };
 
     let config = Config::load_with_cli_overrides(cli_kv_overrides, overrides)?;
-    let mut event_processor = EventProcessor::create_with_ansi(stdout_with_ansi);
+    let mut event_processor =
+        EventProcessor::create_with_ansi(stdout_with_ansi, !config.hide_agent_reasoning);
     // Print the effective configuration and prompt so users can see what Codex
     // is using.
     event_processor.print_config_summary(&config, &prompt);

codex-rs/tui/src/chatwidget.rs

@@ -239,9 +239,11 @@ impl ChatWidget<'_> {
                 self.request_redraw();
             }
             EventMsg::AgentReasoning(AgentReasoningEvent { text }) => {
-                self.conversation_history
-                    .add_agent_reasoning(&self.config, text);
-                self.request_redraw();
+                if !self.config.hide_agent_reasoning {
+                    self.conversation_history
+                        .add_agent_reasoning(&self.config, text);
+                    self.request_redraw();
+                }
             }
             EventMsg::TaskStarted => {
                 self.bottom_pane.set_task_running(true);