enable-resume (#3537)

Adding the ability to resume conversations.
we have one verb `resume`. 

Behavior:

`tui`:
`codex resume`: opens session picker
`codex resume --last`: continue last message
`codex resume <session id>`: continue conversation with `session id`

`exec`:
`codex resume --last`: continue last conversation
`codex resume <session id>`: continue conversation with `session id`

Implementation:
- I added a function to find the path in `~/.codex/sessions/` with a
`UUID`. This is helpful in resuming with session id.
- Added the above mentioned flags
- Added lots of testing

codex-rs/Cargo.lock

@@ -666,6 +666,7 @@ dependencies = [
  "bytes",
  "chrono",
  "codex-apply-patch",
+ "codex-file-search",
  "codex-mcp-client",
  "codex-protocol",
  "core_test_support",
@@ -733,6 +734,8 @@ dependencies = [
  "tokio",
  "tracing",
  "tracing-subscriber",
+ "uuid",
+ "walkdir",
  "wiremock",
 ]
 

codex-rs/cli/src/main.rs

@@ -73,6 +73,9 @@ enum Subcommand {
     #[clap(visible_alias = "a")]
     Apply(ApplyCommand),
 
+    /// Resume a previous interactive session (picker by default; use --last to continue the most recent).
+    Resume(ResumeCommand),
+
     /// Internal: generate TypeScript protocol bindings.
     #[clap(hide = true)]
     GenerateTs(GenerateTsCommand),
@@ -85,6 +88,18 @@ struct CompletionCommand {
     shell: Shell,
 }
 
+#[derive(Debug, Parser)]
+struct ResumeCommand {
+    /// Conversation/session id (UUID). When provided, resumes this session.
+    /// If omitted, use --last to pick the most recent recorded session.
+    #[arg(value_name = "SESSION_ID")]
+    session_id: Option<String>,
+
+    /// Continue the most recent session without showing the picker.
+    #[arg(long = "last", default_value_t = false, conflicts_with = "session_id")]
+    last: bool,
+}
+
 #[derive(Debug, Parser)]
 struct DebugArgs {
     #[command(subcommand)]
@@ -143,26 +158,54 @@ fn main() -> anyhow::Result<()> {
 }
 
 async fn cli_main(codex_linux_sandbox_exe: Option<PathBuf>) -> anyhow::Result<()> {
-    let cli = MultitoolCli::parse();
+    let MultitoolCli {
+        config_overrides: root_config_overrides,
+        mut interactive,
+        subcommand,
+    } = MultitoolCli::parse();
 
-    match cli.subcommand {
+    match subcommand {
         None => {
-            let mut tui_cli = cli.interactive;
+            prepend_config_flags(
-            prepend_config_flags(&mut tui_cli.config_overrides, cli.config_overrides);
+                &mut interactive.config_overrides,
-            let usage = codex_tui::run_main(tui_cli, codex_linux_sandbox_exe).await?;
+                root_config_overrides.clone(),
+            );
+            let usage = codex_tui::run_main(interactive, codex_linux_sandbox_exe).await?;
             if !usage.is_zero() {
                 println!("{}", codex_core::protocol::FinalOutput::from(usage));
             }
         }
         Some(Subcommand::Exec(mut exec_cli)) => {
-            prepend_config_flags(&mut exec_cli.config_overrides, cli.config_overrides);
+            prepend_config_flags(
+                &mut exec_cli.config_overrides,
+                root_config_overrides.clone(),
+            );
             codex_exec::run_main(exec_cli, codex_linux_sandbox_exe).await?;
         }
         Some(Subcommand::Mcp) => {
-            codex_mcp_server::run_main(codex_linux_sandbox_exe, cli.config_overrides).await?;
+            codex_mcp_server::run_main(codex_linux_sandbox_exe, root_config_overrides.clone())
+                .await?;
+        }
+        Some(Subcommand::Resume(ResumeCommand { session_id, last })) => {
+            // Start with the parsed interactive CLI so resume shares the same
+            // configuration surface area as `codex` without additional flags.
+            let resume_session_id = session_id;
+            interactive.resume_picker = resume_session_id.is_none() && !last;
+            interactive.resume_last = last;
+            interactive.resume_session_id = resume_session_id;
+
+            // Propagate any root-level config overrides (e.g. `-c key=value`).
+            prepend_config_flags(
+                &mut interactive.config_overrides,
+                root_config_overrides.clone(),
+            );
+            codex_tui::run_main(interactive, codex_linux_sandbox_exe).await?;
         }
         Some(Subcommand::Login(mut login_cli)) => {
-            prepend_config_flags(&mut login_cli.config_overrides, cli.config_overrides);
+            prepend_config_flags(
+                &mut login_cli.config_overrides,
+                root_config_overrides.clone(),
+            );
             match login_cli.action {
                 Some(LoginSubcommand::Status) => {
                     run_login_status(login_cli.config_overrides).await;
@@ -177,11 +220,17 @@ async fn cli_main(codex_linux_sandbox_exe: Option<PathBuf>) -> anyhow::Result<()
             }
         }
         Some(Subcommand::Logout(mut logout_cli)) => {
-            prepend_config_flags(&mut logout_cli.config_overrides, cli.config_overrides);
+            prepend_config_flags(
+                &mut logout_cli.config_overrides,
+                root_config_overrides.clone(),
+            );
             run_logout(logout_cli.config_overrides).await;
         }
         Some(Subcommand::Proto(mut proto_cli)) => {
-            prepend_config_flags(&mut proto_cli.config_overrides, cli.config_overrides);
+            prepend_config_flags(
+                &mut proto_cli.config_overrides,
+                root_config_overrides.clone(),
+            );
             proto::run_main(proto_cli).await?;
         }
         Some(Subcommand::Completion(completion_cli)) => {
@@ -189,7 +238,10 @@ async fn cli_main(codex_linux_sandbox_exe: Option<PathBuf>) -> anyhow::Result<()
         }
         Some(Subcommand::Debug(debug_args)) => match debug_args.cmd {
             DebugCommand::Seatbelt(mut seatbelt_cli) => {
-                prepend_config_flags(&mut seatbelt_cli.config_overrides, cli.config_overrides);
+                prepend_config_flags(
+                    &mut seatbelt_cli.config_overrides,
+                    root_config_overrides.clone(),
+                );
                 codex_cli::debug_sandbox::run_command_under_seatbelt(
                     seatbelt_cli,
                     codex_linux_sandbox_exe,
@@ -197,7 +249,10 @@ async fn cli_main(codex_linux_sandbox_exe: Option<PathBuf>) -> anyhow::Result<()
                 .await?;
             }
             DebugCommand::Landlock(mut landlock_cli) => {
-                prepend_config_flags(&mut landlock_cli.config_overrides, cli.config_overrides);
+                prepend_config_flags(
+                    &mut landlock_cli.config_overrides,
+                    root_config_overrides.clone(),
+                );
                 codex_cli::debug_sandbox::run_command_under_landlock(
                     landlock_cli,
                     codex_linux_sandbox_exe,
@@ -206,7 +261,10 @@ async fn cli_main(codex_linux_sandbox_exe: Option<PathBuf>) -> anyhow::Result<()
             }
         },
         Some(Subcommand::Apply(mut apply_cli)) => {
-            prepend_config_flags(&mut apply_cli.config_overrides, cli.config_overrides);
+            prepend_config_flags(
+                &mut apply_cli.config_overrides,
+                root_config_overrides.clone(),
+            );
             run_apply_command(apply_cli, None).await?;
         }
         Some(Subcommand::GenerateTs(gen_cli)) => {

codex-rs/core/Cargo.toml

@@ -19,6 +19,7 @@ base64 = "0.22"
 bytes = "1.10.1"
 chrono = { version = "0.4", features = ["serde"] }
 codex-apply-patch = { path = "../apply-patch" }
+codex-file-search = { path = "../file-search" }
 codex-mcp-client = { path = "../mcp-client" }
 codex-protocol = { path = "../protocol" }
 dirs = "6"

codex-rs/core/src/config.rs

@@ -161,9 +161,6 @@ pub struct Config {
     /// Base URL for requests to ChatGPT (as opposed to the OpenAI API).
     pub chatgpt_base_url: String,
 
-    /// Experimental rollout resume path (absolute path to .jsonl; undocumented).
-    pub experimental_resume: Option<PathBuf>,
-
     /// Include an experimental plan tool that the model can use to update its current plan and status of each step.
     pub include_plan_tool: bool,
 
@@ -603,9 +600,6 @@ pub struct ConfigToml {
     /// Base URL for requests to ChatGPT (as opposed to the OpenAI API).
     pub chatgpt_base_url: Option<String>,
 
-    /// Experimental rollout resume path (absolute path to .jsonl; undocumented).
-    pub experimental_resume: Option<PathBuf>,
-
     /// Experimental path to a file whose contents replace the built-in BASE_INSTRUCTIONS.
     pub experimental_instructions_file: Option<PathBuf>,
 
@@ -892,8 +886,6 @@ impl Config {
                 .and_then(|info| info.auto_compact_token_limit)
         });
 
-        let experimental_resume = cfg.experimental_resume;
-
         // Load base instructions override from a file if specified. If the
         // path is relative, resolve it against the effective cwd so the
         // behaviour matches other path-like config values.
@@ -954,8 +946,6 @@ impl Config {
                 .chatgpt_base_url
                 .or(cfg.chatgpt_base_url)
                 .unwrap_or("https://chatgpt.com/backend-api/".to_string()),
-
-            experimental_resume,
             include_plan_tool: include_plan_tool.unwrap_or(false),
             include_apply_patch_tool: include_apply_patch_tool.unwrap_or(false),
             tools_web_search_request,
@@ -1481,7 +1471,6 @@ model_verbosity = "high"
                 model_reasoning_summary: ReasoningSummary::Detailed,
                 model_verbosity: None,
                 chatgpt_base_url: "https://chatgpt.com/backend-api/".to_string(),
-                experimental_resume: None,
                 base_instructions: None,
                 include_plan_tool: false,
                 include_apply_patch_tool: false,
@@ -1539,7 +1528,6 @@ model_verbosity = "high"
             model_reasoning_summary: ReasoningSummary::default(),
             model_verbosity: None,
             chatgpt_base_url: "https://chatgpt.com/backend-api/".to_string(),
-            experimental_resume: None,
             base_instructions: None,
             include_plan_tool: false,
             include_apply_patch_tool: false,
@@ -1612,7 +1600,6 @@ model_verbosity = "high"
             model_reasoning_summary: ReasoningSummary::default(),
             model_verbosity: None,
             chatgpt_base_url: "https://chatgpt.com/backend-api/".to_string(),
-            experimental_resume: None,
             base_instructions: None,
             include_plan_tool: false,
             include_apply_patch_tool: false,
@@ -1671,7 +1658,6 @@ model_verbosity = "high"
             model_reasoning_summary: ReasoningSummary::Detailed,
             model_verbosity: Some(Verbosity::High),
             chatgpt_base_url: "https://chatgpt.com/backend-api/".to_string(),
-            experimental_resume: None,
             base_instructions: None,
             include_plan_tool: false,
             include_apply_patch_tool: false,

codex-rs/core/src/conversation_manager.rs

@@ -59,21 +59,11 @@ impl ConversationManager {
         config: Config,
         auth_manager: Arc<AuthManager>,
     ) -> CodexResult<NewConversation> {
-        // TO BE REFACTORED: use the config experimental_resume field until we have a mainstream way.
+        let CodexSpawnOk {
-        if let Some(resume_path) = config.experimental_resume.as_ref() {
+            codex,
-            let initial_history = RolloutRecorder::get_rollout_history(resume_path).await?;
+            conversation_id,
-            let CodexSpawnOk {
+        } = Codex::spawn(config, auth_manager, InitialHistory::New).await?;
-                codex,
+        self.finalize_spawn(codex, conversation_id).await
-                conversation_id,
-            } = Codex::spawn(config, auth_manager, initial_history).await?;
-            self.finalize_spawn(codex, conversation_id).await
-        } else {
-            let CodexSpawnOk {
-                codex,
-                conversation_id,
-            } = Codex::spawn(config, auth_manager, InitialHistory::New).await?;
-            self.finalize_spawn(codex, conversation_id).await
-        }
     }
 
     async fn finalize_spawn(

codex-rs/core/src/lib.rs

@@ -70,6 +70,7 @@ pub use rollout::ARCHIVED_SESSIONS_SUBDIR;
 pub use rollout::RolloutRecorder;
 pub use rollout::SESSIONS_SUBDIR;
 pub use rollout::SessionMeta;
+pub use rollout::find_conversation_path_by_id_str;
 pub use rollout::list::ConversationItem;
 pub use rollout::list::ConversationsPage;
 pub use rollout::list::Cursor;

codex-rs/core/src/rollout/list.rs

@@ -3,6 +3,10 @@ use std::io::{self};
 use std::path::Path;
 use std::path::PathBuf;
 
+use codex_file_search as file_search;
+use std::num::NonZero;
+use std::sync::Arc;
+use std::sync::atomic::AtomicBool;
 use time::OffsetDateTime;
 use time::PrimitiveDateTime;
 use time::format_description::FormatItem;
@@ -334,3 +338,48 @@ async fn read_head_and_flags(
 
     Ok((head, saw_session_meta, saw_user_event))
 }
+
+/// Locate a recorded conversation rollout file by its UUID string using the existing
+/// paginated listing implementation. Returns `Ok(Some(path))` if found, `Ok(None)` if not present
+/// or the id is invalid.
+pub async fn find_conversation_path_by_id_str(
+    codex_home: &Path,
+    id_str: &str,
+) -> io::Result<Option<PathBuf>> {
+    // Validate UUID format early.
+    if Uuid::parse_str(id_str).is_err() {
+        return Ok(None);
+    }
+
+    let mut root = codex_home.to_path_buf();
+    root.push(SESSIONS_SUBDIR);
+    if !root.exists() {
+        return Ok(None);
+    }
+    // This is safe because we know the values are valid.
+    #[allow(clippy::unwrap_used)]
+    let limit = NonZero::new(1).unwrap();
+    // This is safe because we know the values are valid.
+    #[allow(clippy::unwrap_used)]
+    let threads = NonZero::new(2).unwrap();
+    let cancel = Arc::new(AtomicBool::new(false));
+    let exclude: Vec<String> = Vec::new();
+    let compute_indices = false;
+
+    let results = file_search::run(
+        id_str,
+        limit,
+        &root,
+        exclude,
+        threads,
+        cancel,
+        compute_indices,
+    )
+    .map_err(|e| io::Error::other(format!("file search failed: {e}")))?;
+
+    Ok(results
+        .matches
+        .into_iter()
+        .next()
+        .map(|m| root.join(m.path)))
+}

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

@@ -8,6 +8,7 @@ pub(crate) mod policy;
 pub mod recorder;
 
 pub use codex_protocol::protocol::SessionMeta;
+pub use list::find_conversation_path_by_id_str;
 pub use recorder::RolloutRecorder;
 pub use recorder::RolloutRecorderParams;
 

codex-rs/core/src/rollout/recorder.rs

@@ -204,7 +204,6 @@ impl RolloutRecorder {
 
     pub(crate) async fn get_rollout_history(path: &Path) -> std::io::Result<InitialHistory> {
         info!("Resuming rollout from {path:?}");
-        tracing::error!("Resuming rollout from {path:?}");
         let text = tokio::fs::read_to_string(path).await?;
         if text.trim().is_empty() {
             return Err(IoError::other("empty session file"));
@@ -254,7 +253,7 @@ impl RolloutRecorder {
             }
         }
 
-        tracing::error!(
+        info!(
             "Resumed rollout with {} items, conversation ID: {:?}",
             items.len(),
             conversation_id

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

@@ -420,12 +420,6 @@ async fn integration_creates_and_checks_session_file() {
     // Second run: resume should update the existing file.
     let marker2 = format!("integration-resume-{}", Uuid::new_v4());
     let prompt2 = format!("echo {marker2}");
-    // Cross‑platform safe resume override.  On Windows, backslashes in a TOML string must be escaped
-    // or the parse will fail and the raw literal (including quotes) may be preserved all the way down
-    // to Config, which in turn breaks resume because the path is invalid. Normalize to forward slashes
-    // to sidestep the issue.
-    let resume_path_str = path.to_string_lossy().replace('\\', "/");
-    let resume_override = format!("experimental_resume=\"{resume_path_str}\"");
     let mut cmd2 = AssertCommand::new("cargo");
     cmd2.arg("run")
         .arg("-p")
@@ -434,11 +428,11 @@ async fn integration_creates_and_checks_session_file() {
         .arg("--")
         .arg("exec")
         .arg("--skip-git-repo-check")
-        .arg("-c")
-        .arg(&resume_override)
         .arg("-C")
         .arg(env!("CARGO_MANIFEST_DIR"))
-        .arg(&prompt2);
+        .arg(&prompt2)
+        .arg("resume")
+        .arg("--last");
     cmd2.env("CODEX_HOME", home.path())
         .env("OPENAI_API_KEY", "dummy")
         .env("CODEX_RS_SSE_FIXTURE", &fixture)

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

@@ -236,20 +236,21 @@ async fn resume_includes_initial_messages_and_sends_prior_items() {
     let codex_home = TempDir::new().unwrap();
     let mut config = load_default_config_for_test(&codex_home);
     config.model_provider = model_provider;
-    config.experimental_resume = Some(session_path.clone());
     // Also configure user instructions to ensure they are NOT delivered on resume.
     config.user_instructions = Some("be nice".to_string());
 
     let conversation_manager =
         ConversationManager::with_auth(CodexAuth::from_api_key("Test API Key"));
+    let auth_manager =
+        codex_core::AuthManager::from_auth_for_testing(CodexAuth::from_api_key("Test API Key"));
     let NewConversation {
         conversation: codex,
         session_configured,
         ..
     } = conversation_manager
-        .new_conversation(config)
+        .resume_conversation_from_rollout(config, session_path.clone(), auth_manager)
         .await
-        .expect("create new conversation");
+        .expect("resume conversation");
 
     // 1) Assert initial_messages only includes existing EventMsg entries; response items are not converted
     let initial_msgs = session_configured

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

@@ -11,6 +11,7 @@ mod live_cli;
 mod model_overrides;
 mod prompt_caching;
 mod review;
+mod rollout_list_find;
 mod seatbelt;
 mod stream_error_allows_next_turn;
 mod stream_no_completed;

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

@@ -379,13 +379,8 @@ async fn review_input_isolated_from_parent_history() {
             .await
             .unwrap();
     }
-    config.experimental_resume = Some(session_file);
+    let codex =
-
+        resume_conversation_for_server(&server, &codex_home, session_file.clone(), |_| {}).await;
-    let codex = new_conversation_for_server(&server, &codex_home, |cfg| {
-        // apply resume file
-        cfg.experimental_resume = config.experimental_resume.clone();
-    })
-    .await;
 
     // Submit review request; it must start fresh (no parent history in `input`).
     let review_prompt = "Please review only this".to_string();
@@ -546,3 +541,32 @@ where
         .expect("create conversation")
         .conversation
 }
+
+/// Create a conversation resuming from a rollout file, configured to talk to the provided mock server.
+#[expect(clippy::expect_used)]
+async fn resume_conversation_for_server<F>(
+    server: &MockServer,
+    codex_home: &TempDir,
+    resume_path: std::path::PathBuf,
+    mutator: F,
+) -> Arc<CodexConversation>
+where
+    F: FnOnce(&mut Config),
+{
+    let model_provider = ModelProviderInfo {
+        base_url: Some(format!("{}/v1", server.uri())),
+        ..built_in_model_providers()["openai"].clone()
+    };
+    let mut config = load_default_config_for_test(codex_home);
+    config.model_provider = model_provider;
+    mutator(&mut config);
+    let conversation_manager =
+        ConversationManager::with_auth(CodexAuth::from_api_key("Test API Key"));
+    let auth_manager =
+        codex_core::AuthManager::from_auth_for_testing(CodexAuth::from_api_key("Test API Key"));
+    conversation_manager
+        .resume_conversation_from_rollout(config, resume_path, auth_manager)
+        .await
+        .expect("resume conversation")
+        .conversation
+}

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

@@ -0,0 +1,50 @@
+#![allow(clippy::unwrap_used, clippy::expect_used)]
+use std::io::Write;
+use std::path::PathBuf;
+
+use codex_core::find_conversation_path_by_id_str;
+use tempfile::TempDir;
+use uuid::Uuid;
+
+/// Create sessions/YYYY/MM/DD and write a minimal rollout file containing the
+/// provided conversation id in the SessionMeta line. Returns the absolute path.
+fn write_minimal_rollout_with_id(codex_home: &TempDir, id: Uuid) -> PathBuf {
+    let sessions = codex_home.path().join("sessions/2024/01/01");
+    std::fs::create_dir_all(&sessions).unwrap();
+
+    let file = sessions.join(format!("rollout-2024-01-01T00-00-00-{id}.jsonl"));
+    let mut f = std::fs::File::create(&file).unwrap();
+    // Minimal first line: session_meta with the id so content search can find it
+    writeln!(
+        f,
+        "{}",
+        serde_json::json!({
+            "timestamp": "2024-01-01T00:00:00.000Z",
+            "type": "session_meta",
+            "payload": {
+                "id": id,
+                "timestamp": "2024-01-01T00:00:00Z",
+                "instructions": null,
+                "cwd": ".",
+                "originator": "test",
+                "cli_version": "test"
+            }
+        })
+    )
+    .unwrap();
+
+    file
+}
+
+#[tokio::test]
+async fn find_locates_rollout_file_by_id() {
+    let home = TempDir::new().unwrap();
+    let id = Uuid::new_v4();
+    let expected = write_minimal_rollout_with_id(&home, id);
+
+    let found = find_conversation_path_by_id_str(home.path(), &id.to_string())
+        .await
+        .unwrap();
+
+    assert_eq!(found.unwrap(), expected);
+}

codex-rs/exec/Cargo.toml

@@ -46,4 +46,6 @@ core_test_support = { path = "../core/tests/common" }
 libc = "0.2"
 predicates = "3"
 tempfile = "3.13.0"
+uuid = "1"
+walkdir = "2"
 wiremock = "0.6"

codex-rs/exec/src/cli.rs

@@ -6,6 +6,10 @@ use std::path::PathBuf;
 #[derive(Parser, Debug)]
 #[command(version)]
 pub struct Cli {
+    /// Action to perform. If omitted, runs a new non-interactive session.
+    #[command(subcommand)]
+    pub command: Option<Command>,
+
     /// Optional image(s) to attach to the initial prompt.
     #[arg(long = "image", short = 'i', value_name = "FILE", value_delimiter = ',', num_args = 1..)]
     pub images: Vec<PathBuf>,
@@ -69,6 +73,28 @@ pub struct Cli {
     pub prompt: Option<String>,
 }
 
+#[derive(Debug, clap::Subcommand)]
+pub enum Command {
+    /// Resume a previous session by id or pick the most recent with --last.
+    Resume(ResumeArgs),
+}
+
+#[derive(Parser, Debug)]
+pub struct ResumeArgs {
+    /// Conversation/session id (UUID). When provided, resumes this session.
+    /// If omitted, use --last to pick the most recent recorded session.
+    #[arg(value_name = "SESSION_ID")]
+    pub session_id: Option<String>,
+
+    /// Resume the most recent recorded session (newest) without specifying an id.
+    #[arg(long = "last", default_value_t = false, conflicts_with = "session_id")]
+    pub last: bool,
+
+    /// Prompt to send after resuming the session. If `-` is used, read from stdin.
+    #[arg(value_name = "PROMPT")]
+    pub prompt: Option<String>,
+}
+
 #[derive(Debug, Clone, Copy, Default, PartialEq, Eq, ValueEnum)]
 #[value(rename_all = "kebab-case")]
 pub enum Color {

codex-rs/exec/src/lib.rs

@@ -30,11 +30,14 @@ use tracing::error;
 use tracing::info;
 use tracing_subscriber::EnvFilter;
 
+use crate::cli::Command as ExecCommand;
 use crate::event_processor::CodexStatus;
 use crate::event_processor::EventProcessor;
+use codex_core::find_conversation_path_by_id_str;
 
 pub async fn run_main(cli: Cli, codex_linux_sandbox_exe: Option<PathBuf>) -> anyhow::Result<()> {
     let Cli {
+        command,
         images,
         model: model_cli_arg,
         oss,
@@ -51,8 +54,15 @@ pub async fn run_main(cli: Cli, codex_linux_sandbox_exe: Option<PathBuf>) -> any
         config_overrides,
     } = cli;
 
-    // Determine the prompt based on CLI arg and/or stdin.
+    // Determine the prompt source (parent or subcommand) and read from stdin if needed.
-    let prompt = match prompt {
+    let prompt_arg = match &command {
+        // Allow prompt before the subcommand by falling back to the parent-level prompt
+        // when the Resume subcommand did not provide its own prompt.
+        Some(ExecCommand::Resume(args)) => args.prompt.clone().or(prompt),
+        None => prompt,
+    };
+
+    let prompt = match prompt_arg {
         Some(p) if p != "-" => p,
         // Either `-` was passed or no positional arg.
         maybe_dash => {
@@ -190,11 +200,29 @@ pub async fn run_main(cli: Cli, codex_linux_sandbox_exe: Option<PathBuf>) -> any
 
     let conversation_manager =
         ConversationManager::new(AuthManager::shared(config.codex_home.clone()));
+
+    // Handle resume subcommand by resolving a rollout path and using explicit resume API.
     let NewConversation {
         conversation_id: _,
         conversation,
         session_configured,
-    } = conversation_manager.new_conversation(config).await?;
+    } = if let Some(ExecCommand::Resume(args)) = command {
+        let resume_path = resolve_resume_path(&config, &args).await?;
+
+        if let Some(path) = resume_path {
+            conversation_manager
+                .resume_conversation_from_rollout(
+                    config.clone(),
+                    path,
+                    AuthManager::shared(config.codex_home.clone()),
+                )
+                .await?
+        } else {
+            conversation_manager.new_conversation(config).await?
+        }
+    } else {
+        conversation_manager.new_conversation(config).await?
+    };
     info!("Codex initialized with event: {session_configured:?}");
 
     let (tx, mut rx) = tokio::sync::mpsc::unbounded_channel::<Event>();
@@ -279,3 +307,23 @@ pub async fn run_main(cli: Cli, codex_linux_sandbox_exe: Option<PathBuf>) -> any
 
     Ok(())
 }
+
+async fn resolve_resume_path(
+    config: &Config,
+    args: &crate::cli::ResumeArgs,
+) -> anyhow::Result<Option<PathBuf>> {
+    if args.last {
+        match codex_core::RolloutRecorder::list_conversations(&config.codex_home, 1, None).await {
+            Ok(page) => Ok(page.items.first().map(|it| it.path.clone())),
+            Err(e) => {
+                error!("Error listing conversations: {e}");
+                Ok(None)
+            }
+        }
+    } else if let Some(id_str) = args.session_id.as_deref() {
+        let path = find_conversation_path_by_id_str(&config.codex_home, id_str).await?;
+        Ok(path)
+    } else {
+        Ok(None)
+    }
+}

codex-rs/exec/tests/fixtures/cli_responses_fixture.sse

@@ -0,0 +1,10 @@
+event: response.created
+data: {"type":"response.created","response":{"id":"resp1"}}
+
+event: response.output_item.done
+data: {"type":"response.output_item.done","item":{"type":"message","role":"assistant","content":[{"type":"output_text","text":"fixture hello"}]}}
+
+event: response.completed
+data: {"type":"response.completed","response":{"id":"resp1","output":[]}}
+
+

codex-rs/exec/tests/suite/mod.rs

@@ -1,4 +1,5 @@
 // Aggregates all former standalone integration tests as modules.
 mod apply_patch;
 mod common;
+mod resume;
 mod sandbox;

codex-rs/exec/tests/suite/resume.rs

@@ -0,0 +1,267 @@
+#![allow(clippy::unwrap_used, clippy::expect_used)]
+use anyhow::Context;
+use assert_cmd::prelude::*;
+use serde_json::Value;
+use std::process::Command;
+use tempfile::TempDir;
+use uuid::Uuid;
+use walkdir::WalkDir;
+
+/// Utility: scan the sessions dir for a rollout file that contains `marker`
+/// in any response_item.message.content entry. Returns the absolute path.
+fn find_session_file_containing_marker(
+    sessions_dir: &std::path::Path,
+    marker: &str,
+) -> Option<std::path::PathBuf> {
+    for entry in WalkDir::new(sessions_dir) {
+        let entry = match entry {
+            Ok(e) => e,
+            Err(_) => continue,
+        };
+        if !entry.file_type().is_file() {
+            continue;
+        }
+        if !entry.file_name().to_string_lossy().ends_with(".jsonl") {
+            continue;
+        }
+        let path = entry.path();
+        let Ok(content) = std::fs::read_to_string(path) else {
+            continue;
+        };
+        // Skip the first meta line and scan remaining JSONL entries.
+        let mut lines = content.lines();
+        if lines.next().is_none() {
+            continue;
+        }
+        for line in lines {
+            if line.trim().is_empty() {
+                continue;
+            }
+            let Ok(item): Result<Value, _> = serde_json::from_str(line) else {
+                continue;
+            };
+            if item.get("type").and_then(|t| t.as_str()) == Some("response_item")
+                && let Some(payload) = item.get("payload")
+                && payload.get("type").and_then(|t| t.as_str()) == Some("message")
+                && payload
+                    .get("content")
+                    .map(|c| c.to_string())
+                    .unwrap_or_default()
+                    .contains(marker)
+            {
+                return Some(path.to_path_buf());
+            }
+        }
+    }
+    None
+}
+
+/// Extract the conversation UUID from the first SessionMeta line in the rollout file.
+fn extract_conversation_id(path: &std::path::Path) -> String {
+    let content = std::fs::read_to_string(path).unwrap();
+    let mut lines = content.lines();
+    let meta_line = lines.next().expect("missing meta line");
+    let meta: Value = serde_json::from_str(meta_line).expect("invalid meta json");
+    meta.get("payload")
+        .and_then(|p| p.get("id"))
+        .and_then(|v| v.as_str())
+        .unwrap_or_default()
+        .to_string()
+}
+
+#[test]
+fn exec_resume_last_appends_to_existing_file() -> anyhow::Result<()> {
+    let home = TempDir::new()?;
+    let fixture = std::path::Path::new(env!("CARGO_MANIFEST_DIR"))
+        .join("tests/fixtures/cli_responses_fixture.sse");
+
+    // 1) First run: create a session with a unique marker in the content.
+    let marker = format!("resume-last-{}", Uuid::new_v4());
+    let prompt = format!("echo {marker}");
+
+    Command::cargo_bin("codex-exec")
+        .context("should find binary for codex-exec")?
+        .env("CODEX_HOME", home.path())
+        .env("OPENAI_API_KEY", "dummy")
+        .env("CODEX_RS_SSE_FIXTURE", &fixture)
+        .env("OPENAI_BASE_URL", "http://unused.local")
+        .arg("--skip-git-repo-check")
+        .arg("-C")
+        .arg(env!("CARGO_MANIFEST_DIR"))
+        .arg(&prompt)
+        .assert()
+        .success();
+
+    // Find the created session file containing the marker.
+    let sessions_dir = home.path().join("sessions");
+    let path = find_session_file_containing_marker(&sessions_dir, &marker)
+        .expect("no session file found after first run");
+
+    // 2) Second run: resume the most recent file with a new marker.
+    let marker2 = format!("resume-last-2-{}", Uuid::new_v4());
+    let prompt2 = format!("echo {marker2}");
+
+    let mut binding = assert_cmd::Command::cargo_bin("codex-exec")
+        .context("should find binary for codex-exec")?;
+    let cmd = binding
+        .env("CODEX_HOME", home.path())
+        .env("OPENAI_API_KEY", "dummy")
+        .env("CODEX_RS_SSE_FIXTURE", &fixture)
+        .env("OPENAI_BASE_URL", "http://unused.local")
+        .arg("--skip-git-repo-check")
+        .arg("-C")
+        .arg(env!("CARGO_MANIFEST_DIR"))
+        .arg(&prompt2)
+        .arg("resume")
+        .arg("--last");
+    cmd.assert().success();
+
+    // Ensure the same file was updated and contains both markers.
+    let resumed_path = find_session_file_containing_marker(&sessions_dir, &marker2)
+        .expect("no resumed session file containing marker2");
+    assert_eq!(
+        resumed_path, path,
+        "resume --last should append to existing file"
+    );
+    let content = std::fs::read_to_string(&resumed_path)?;
+    assert!(content.contains(&marker));
+    assert!(content.contains(&marker2));
+    Ok(())
+}
+
+#[test]
+fn exec_resume_by_id_appends_to_existing_file() -> anyhow::Result<()> {
+    let home = TempDir::new()?;
+    let fixture = std::path::Path::new(env!("CARGO_MANIFEST_DIR"))
+        .join("tests/fixtures/cli_responses_fixture.sse");
+
+    // 1) First run: create a session
+    let marker = format!("resume-by-id-{}", Uuid::new_v4());
+    let prompt = format!("echo {marker}");
+
+    Command::cargo_bin("codex-exec")
+        .context("should find binary for codex-exec")?
+        .env("CODEX_HOME", home.path())
+        .env("OPENAI_API_KEY", "dummy")
+        .env("CODEX_RS_SSE_FIXTURE", &fixture)
+        .env("OPENAI_BASE_URL", "http://unused.local")
+        .arg("--skip-git-repo-check")
+        .arg("-C")
+        .arg(env!("CARGO_MANIFEST_DIR"))
+        .arg(&prompt)
+        .assert()
+        .success();
+
+    let sessions_dir = home.path().join("sessions");
+    let path = find_session_file_containing_marker(&sessions_dir, &marker)
+        .expect("no session file found after first run");
+    let session_id = extract_conversation_id(&path);
+    assert!(
+        !session_id.is_empty(),
+        "missing conversation id in meta line"
+    );
+
+    // 2) Resume by id
+    let marker2 = format!("resume-by-id-2-{}", Uuid::new_v4());
+    let prompt2 = format!("echo {marker2}");
+
+    let mut binding = assert_cmd::Command::cargo_bin("codex-exec")
+        .context("should find binary for codex-exec")?;
+    let cmd = binding
+        .env("CODEX_HOME", home.path())
+        .env("OPENAI_API_KEY", "dummy")
+        .env("CODEX_RS_SSE_FIXTURE", &fixture)
+        .env("OPENAI_BASE_URL", "http://unused.local")
+        .arg("--skip-git-repo-check")
+        .arg("-C")
+        .arg(env!("CARGO_MANIFEST_DIR"))
+        .arg(&prompt2)
+        .arg("resume")
+        .arg(&session_id);
+    cmd.assert().success();
+
+    let resumed_path = find_session_file_containing_marker(&sessions_dir, &marker2)
+        .expect("no resumed session file containing marker2");
+    assert_eq!(
+        resumed_path, path,
+        "resume by id should append to existing file"
+    );
+    let content = std::fs::read_to_string(&resumed_path)?;
+    assert!(content.contains(&marker));
+    assert!(content.contains(&marker2));
+    Ok(())
+}
+
+#[test]
+fn exec_resume_preserves_cli_configuration_overrides() -> anyhow::Result<()> {
+    let home = TempDir::new()?;
+    let fixture = std::path::Path::new(env!("CARGO_MANIFEST_DIR"))
+        .join("tests/fixtures/cli_responses_fixture.sse");
+
+    let marker = format!("resume-config-{}", Uuid::new_v4());
+    let prompt = format!("echo {marker}");
+
+    Command::cargo_bin("codex-exec")
+        .context("should find binary for codex-exec")?
+        .env("CODEX_HOME", home.path())
+        .env("OPENAI_API_KEY", "dummy")
+        .env("CODEX_RS_SSE_FIXTURE", &fixture)
+        .env("OPENAI_BASE_URL", "http://unused.local")
+        .arg("--skip-git-repo-check")
+        .arg("--sandbox")
+        .arg("workspace-write")
+        .arg("--model")
+        .arg("gpt-5")
+        .arg("-C")
+        .arg(env!("CARGO_MANIFEST_DIR"))
+        .arg(&prompt)
+        .assert()
+        .success();
+
+    let sessions_dir = home.path().join("sessions");
+    let path = find_session_file_containing_marker(&sessions_dir, &marker)
+        .expect("no session file found after first run");
+
+    let marker2 = format!("resume-config-2-{}", Uuid::new_v4());
+    let prompt2 = format!("echo {marker2}");
+
+    let output = Command::cargo_bin("codex-exec")
+        .context("should find binary for codex-exec")?
+        .env("CODEX_HOME", home.path())
+        .env("OPENAI_API_KEY", "dummy")
+        .env("CODEX_RS_SSE_FIXTURE", &fixture)
+        .env("OPENAI_BASE_URL", "http://unused.local")
+        .arg("--skip-git-repo-check")
+        .arg("--sandbox")
+        .arg("workspace-write")
+        .arg("--model")
+        .arg("gpt-5-high")
+        .arg("-C")
+        .arg(env!("CARGO_MANIFEST_DIR"))
+        .arg(&prompt2)
+        .arg("resume")
+        .arg("--last")
+        .output()
+        .context("resume run should succeed")?;
+
+    assert!(output.status.success(), "resume run failed: {output:?}");
+
+    let stdout = String::from_utf8(output.stdout)?;
+    assert!(
+        stdout.contains("model: gpt-5-high"),
+        "stdout missing model override: {stdout}"
+    );
+    assert!(
+        stdout.contains("sandbox: workspace-write"),
+        "stdout missing sandbox override: {stdout}"
+    );
+
+    let resumed_path = find_session_file_containing_marker(&sessions_dir, &marker2)
+        .expect("no resumed session file containing marker2");
+    assert_eq!(resumed_path, path, "resume should append to same file");
+
+    let content = std::fs::read_to_string(&resumed_path)?;
+    assert!(content.contains(&marker));
+    assert!(content.contains(&marker2));
+    Ok(())
+}

codex-rs/tui/src/cli.rs

@@ -13,35 +13,18 @@ pub struct Cli {
     #[arg(long = "image", short = 'i', value_name = "FILE", value_delimiter = ',', num_args = 1..)]
     pub images: Vec<PathBuf>,
 
-    /// Open an interactive picker to resume a previous session recorded on disk
+    // Internal controls set by the top-level `codex resume` subcommand.
-    /// instead of starting a new one.
+    // These are not exposed as user flags on the base `codex` command.
-    ///
+    #[clap(skip)]
-    /// Notes:
+    pub resume_picker: bool,
-    /// - Mutually exclusive with `--continue`.
-    /// - The picker displays recent sessions and a preview of the first real user
-    ///   message to help you select the right one.
-    #[arg(
-        long = "resume",
-        default_value_t = false,
-        conflicts_with = "continue",
-        hide = true
-    )]
-    pub resume: bool,
 
-    /// Continue the most recent conversation without showing the picker.
+    #[clap(skip)]
-    ///
+    pub resume_last: bool,
-    /// Notes:
+
-    /// - Mutually exclusive with `--resume`.
+    /// Internal: resume a specific recorded session by id (UUID). Set by the
-    /// - If no recorded sessions are found, this behaves like starting fresh.
+    /// top-level `codex resume <SESSION_ID>` wrapper; not exposed as a public flag.
-    /// - Equivalent to picking the newest item in the resume picker.
+    #[clap(skip)]
-    #[arg(
+    pub resume_session_id: Option<String>,
-        id = "continue",
-        long = "continue",
-        default_value_t = false,
-        conflicts_with = "resume",
-        hide = true
-    )]
-    pub r#continue: bool,
 
     /// Model the agent should use.
     #[arg(long, short = 'm')]

codex-rs/tui/src/lib.rs

@@ -15,6 +15,7 @@ use codex_core::config::SWIFTFOX_MEDIUM_MODEL;
 use codex_core::config::find_codex_home;
 use codex_core::config::load_config_as_toml_with_cli_overrides;
 use codex_core::config::persist_model_selection;
+use codex_core::find_conversation_path_by_id_str;
 use codex_core::protocol::AskForApproval;
 use codex_core::protocol::SandboxPolicy;
 use codex_ollama::DEFAULT_OSS_MODEL;
@@ -343,7 +344,16 @@ async fn run_ratatui_app(
         }
     }
 
-    let resume_selection = if cli.r#continue {
+    // Determine resume behavior: explicit id, then resume last, then picker.
+    let resume_selection = if let Some(id_str) = cli.resume_session_id.as_deref() {
+        match find_conversation_path_by_id_str(&config.codex_home, id_str).await? {
+            Some(path) => resume_picker::ResumeSelection::Resume(path),
+            None => {
+                error!("Error finding conversation path: {id_str}");
+                resume_picker::ResumeSelection::StartFresh
+            }
+        }
+    } else if cli.resume_last {
         match RolloutRecorder::list_conversations(&config.codex_home, 1, None).await {
             Ok(page) => page
                 .items
@@ -352,7 +362,7 @@ async fn run_ratatui_app(
                 .unwrap_or(resume_picker::ResumeSelection::StartFresh),
             Err(_) => resume_picker::ResumeSelection::StartFresh,
         }
-    } else if cli.resume {
+    } else if cli.resume_picker {
         match resume_picker::run_resume_picker(&mut tui, &config.codex_home).await? {
             resume_picker::ResumeSelection::Exit => {
                 restore();

docs/advanced.md

@@ -12,6 +12,40 @@ Run Codex head-less in pipelines. Example GitHub Action step:
     codex exec --full-auto "update CHANGELOG for next release"
 ```
 
+### Resuming non-interactive sessions
+
+You can resume a previous headless run to continue the same conversation context and append to the same rollout file.
+
+Interactive TUI equivalent:
+
+```shell
+codex resume             # picker
+codex resume --last      # most recent
+codex resume <SESSION_ID>
+```
+
+Compatibility:
+
+- Latest source builds include `codex exec resume` (examples below).
+- Current released CLI may not include this yet. If `codex exec --help` shows no `resume`, use the workaround in the next subsection.
+
+```shell
+# Resume the most recent recorded session and run with a new prompt (source builds)
+codex exec "ship a release draft changelog" resume --last
+
+# Alternatively, pass the prompt via stdin (source builds)
+# Note: omit the trailing '-' to avoid it being parsed as a SESSION_ID
+echo "ship a release draft changelog" | codex exec resume --last
+
+# Or resume a specific session by id (UUID) (source builds)
+codex exec resume 7f9f9a2e-1b3c-4c7a-9b0e-123456789abc "continue the task"
+```
+
+Notes:
+
+- When using `--last`, Codex picks the newest recorded session; if none exist, it behaves like starting fresh.
+- Resuming appends new events to the existing session file and maintains the same conversation id.
+
 ## Tracing / verbose logging
 
 Because Codex is written in Rust, it honors the `RUST_LOG` environment variable to configure its logging behavior.

docs/getting-started.md

@@ -10,19 +10,24 @@
 
 Key flags: `--model/-m`, `--ask-for-approval/-a`.
 
-<!--
+### Resuming interactive sessions
-Resume options:
 
-- `--resume`: open an interactive picker of recent sessions (shows a preview of the first real user message). Conflicts with `--continue`.
+- Run `codex resume` to display the session picker UI
-- `--continue`: resume the most recent session without showing the picker (falls back to starting fresh if none exist). Conflicts with `--resume`.
+- Resume most recent: `codex resume --last`
+- Resume by id: `codex resume <SESSION_ID>` (You can get session ids from /status or `~/.codex/sessions/`)
 
 Examples:
 
 ```shell
-codex --resume
+# Open a picker of recent sessions
-codex --continue
+codex resume
+
+# Resume the most recent session
+codex resume --last
+
+# Resume a specific session by id
+codex resume 7f9f9a2e-1b3c-4c7a-9b0e-123456789abc
 ```
--->
 
 ### Running with a prompt as input