Add agents.interrupt_message for interruption markers (#19351)

## Why

Agent interruptions currently always persist a model-visible
interrupted-turn marker before emitting `TurnAborted`. That marker is
useful by default because it gives the next model turn context about a
deliberately interrupted task, but some deployments need to suppress
that history injection entirely while still keeping the client-visible
interruption event.

## What changed

- Add `[agents] interrupt_message = false` to disable the model-visible
interrupted-turn marker.
- Resolve the setting into `Config::agent_interrupt_message_enabled`,
defaulting to `true` so existing behavior is unchanged.
- Apply the setting to both live interrupted turns and interrupted fork
snapshots.
- Keep emitting `TurnAborted` even when the history marker is disabled.
- Regenerate `core/config.schema.json` for the new
`agents.interrupt_message` field.

## Testing

- `cargo test -p codex-core load_config_resolves_agent_interrupt_message
-- --nocapture`
- `cargo test -p codex-core
disabled_interrupted_fork_snapshot_appends_only_interrupt_event --
--nocapture`
- `cargo test -p codex-core
multi_agent_v2_interrupted_marker_uses_developer_input_message --
--nocapture`
- `cargo test -p codex-core
multi_agent_v2_followup_task_can_disable_interrupted_marker --
--nocapture`
- `cargo test -p codex-core
multi_agent_v2_followup_task_interrupts_busy_child_without_losing_message
-- --nocapture`
- `cargo check -p codex-core`

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

@@ -3941,6 +3941,7 @@ async fn load_config_rejects_missing_agent_role_config_file() -> std::io::Result
             max_threads: None,
             max_depth: None,
             job_max_runtime_seconds: None,
+            interrupt_message: None,
             roles: BTreeMap::from([(
                 "researcher".to_string(),
                 AgentRoleToml {
@@ -4856,6 +4857,29 @@ model = "gpt-5-mini"
     Ok(())
 }
 
+#[tokio::test]
+async fn load_config_resolves_agent_interrupt_message() -> std::io::Result<()> {
+    let codex_home = TempDir::new()?;
+    let cfg = ConfigToml {
+        agents: Some(AgentsToml {
+            interrupt_message: Some(false),
+            ..Default::default()
+        }),
+        ..Default::default()
+    };
+
+    let config = Config::load_from_base_config_with_overrides(
+        cfg,
+        ConfigOverrides::default(),
+        codex_home.abs(),
+    )
+    .await?;
+
+    assert!(!config.agent_interrupt_message_enabled);
+
+    Ok(())
+}
+
 #[tokio::test]
 async fn load_config_normalizes_agent_role_nickname_candidates() -> std::io::Result<()> {
     let codex_home = TempDir::new()?;
@@ -4864,6 +4888,7 @@ async fn load_config_normalizes_agent_role_nickname_candidates() -> std::io::Res
             max_threads: None,
             max_depth: None,
             job_max_runtime_seconds: None,
+            interrupt_message: None,
             roles: BTreeMap::from([(
                 "researcher".to_string(),
                 AgentRoleToml {
@@ -4906,6 +4931,7 @@ async fn load_config_rejects_empty_agent_role_nickname_candidates() -> std::io::
             max_threads: None,
             max_depth: None,
             job_max_runtime_seconds: None,
+            interrupt_message: None,
             roles: BTreeMap::from([(
                 "researcher".to_string(),
                 AgentRoleToml {
@@ -4942,6 +4968,7 @@ async fn load_config_rejects_duplicate_agent_role_nickname_candidates() -> std::
             max_threads: None,
             max_depth: None,
             job_max_runtime_seconds: None,
+            interrupt_message: None,
             roles: BTreeMap::from([(
                 "researcher".to_string(),
                 AgentRoleToml {
@@ -4978,6 +5005,7 @@ async fn load_config_rejects_unsafe_agent_role_nickname_candidates() -> std::io:
             max_threads: None,
             max_depth: None,
             job_max_runtime_seconds: None,
+            interrupt_message: None,
             roles: BTreeMap::from([(
                 "researcher".to_string(),
                 AgentRoleToml {
@@ -5234,6 +5262,7 @@ async fn test_precedence_fixture_with_o3_profile() -> std::io::Result<()> {
             agent_roles: BTreeMap::new(),
             memories: MemoriesConfig::default(),
             agent_job_max_runtime_seconds: DEFAULT_AGENT_JOB_MAX_RUNTIME_SECONDS,
+            agent_interrupt_message_enabled: true,
             codex_home: fixture.codex_home(),
             sqlite_home: fixture.codex_home().to_path_buf(),
             log_dir: fixture.codex_home().join("log").to_path_buf(),
@@ -5431,6 +5460,7 @@ async fn test_precedence_fixture_with_gpt3_profile() -> std::io::Result<()> {
         agent_roles: BTreeMap::new(),
         memories: MemoriesConfig::default(),
         agent_job_max_runtime_seconds: DEFAULT_AGENT_JOB_MAX_RUNTIME_SECONDS,
+        agent_interrupt_message_enabled: true,
         codex_home: fixture.codex_home(),
         sqlite_home: fixture.codex_home().to_path_buf(),
         log_dir: fixture.codex_home().join("log").to_path_buf(),
@@ -5582,6 +5612,7 @@ async fn test_precedence_fixture_with_zdr_profile() -> std::io::Result<()> {
         agent_roles: BTreeMap::new(),
         memories: MemoriesConfig::default(),
         agent_job_max_runtime_seconds: DEFAULT_AGENT_JOB_MAX_RUNTIME_SECONDS,
+        agent_interrupt_message_enabled: true,
         codex_home: fixture.codex_home(),
         sqlite_home: fixture.codex_home().to_path_buf(),
         log_dir: fixture.codex_home().join("log").to_path_buf(),
@@ -5718,6 +5749,7 @@ async fn test_precedence_fixture_with_gpt5_profile() -> std::io::Result<()> {
         agent_roles: BTreeMap::new(),
         memories: MemoriesConfig::default(),
         agent_job_max_runtime_seconds: DEFAULT_AGENT_JOB_MAX_RUNTIME_SECONDS,
+        agent_interrupt_message_enabled: true,
         codex_home: fixture.codex_home(),
         sqlite_home: fixture.codex_home().to_path_buf(),
         log_dir: fixture.codex_home().join("log").to_path_buf(),

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

@@ -432,6 +432,9 @@ pub struct Config {
     /// Maximum runtime in seconds for agent job workers before they are failed.
     pub agent_job_max_runtime_seconds: Option<u64>,
 
+    /// Whether to record a model-visible message when an agent turn is interrupted.
+    pub agent_interrupt_message_enabled: bool,
+
     /// Maximum nesting depth allowed for spawned agent threads.
     pub agent_max_depth: i32,
 
@@ -2002,6 +2005,11 @@ impl Config {
                 "agents.job_max_runtime_seconds must fit within a 64-bit signed integer",
             ));
         }
+        let agent_interrupt_message_enabled = cfg
+            .agents
+            .as_ref()
+            .and_then(|agents| agents.interrupt_message)
+            .unwrap_or(true);
         let background_terminal_max_timeout = cfg
             .background_terminal_max_timeout
             .unwrap_or(DEFAULT_MAX_BACKGROUND_TERMINAL_TIMEOUT_MS)
@@ -2366,6 +2374,7 @@ impl Config {
             agent_roles,
             memories: cfg.memories.unwrap_or_default().into(),
             agent_job_max_runtime_seconds,
+            agent_interrupt_message_enabled,
             codex_home,
             sqlite_home,
             log_dir,