feat: grep_files as a tool (#4820)

Add `grep_files` to be able to perform more action in parallel

codex-rs/core/src/model_family.rs

@@ -119,9 +119,10 @@ pub fn find_family_for_model(mut slug: &str) -> Option<ModelFamily> {
             reasoning_summary_format: ReasoningSummaryFormat::Experimental,
             base_instructions: GPT_5_CODEX_INSTRUCTIONS.to_string(),
             experimental_supported_tools: vec![
-                "read_file".to_string(),
+                "grep_files".to_string(),
                 "list_dir".to_string(),
-                "test_sync_tool".to_string()
+                "read_file".to_string(),
+                "test_sync_tool".to_string(),
             ],
             supports_parallel_tool_calls: true,
         )
@@ -134,7 +135,11 @@ pub fn find_family_for_model(mut slug: &str) -> Option<ModelFamily> {
             reasoning_summary_format: ReasoningSummaryFormat::Experimental,
             base_instructions: GPT_5_CODEX_INSTRUCTIONS.to_string(),
             apply_patch_tool_type: Some(ApplyPatchToolType::Freeform),
-            experimental_supported_tools: vec!["read_file".to_string(), "list_dir".to_string()],
+            experimental_supported_tools: vec![
+                "grep_files".to_string(),
+                "list_dir".to_string(),
+                "read_file".to_string(),
+            ],
             supports_parallel_tool_calls: true,
         )
 

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

@@ -0,0 +1,272 @@
+use std::path::Path;
+use std::time::Duration;
+
+use async_trait::async_trait;
+use serde::Deserialize;
+use tokio::process::Command;
+use tokio::time::timeout;
+
+use crate::function_tool::FunctionCallError;
+use crate::tools::context::ToolInvocation;
+use crate::tools::context::ToolOutput;
+use crate::tools::context::ToolPayload;
+use crate::tools::registry::ToolHandler;
+use crate::tools::registry::ToolKind;
+
+pub struct GrepFilesHandler;
+
+const DEFAULT_LIMIT: usize = 100;
+const MAX_LIMIT: usize = 2000;
+const COMMAND_TIMEOUT: Duration = Duration::from_secs(30);
+
+fn default_limit() -> usize {
+    DEFAULT_LIMIT
+}
+
+#[derive(Deserialize)]
+struct GrepFilesArgs {
+    pattern: String,
+    #[serde(default)]
+    include: Option<String>,
+    #[serde(default)]
+    path: Option<String>,
+    #[serde(default = "default_limit")]
+    limit: usize,
+}
+
+#[async_trait]
+impl ToolHandler for GrepFilesHandler {
+    fn kind(&self) -> ToolKind {
+        ToolKind::Function
+    }
+
+    async fn handle(&self, invocation: ToolInvocation) -> Result<ToolOutput, FunctionCallError> {
+        let ToolInvocation { payload, turn, .. } = invocation;
+
+        let arguments = match payload {
+            ToolPayload::Function { arguments } => arguments,
+            _ => {
+                return Err(FunctionCallError::RespondToModel(
+                    "grep_files handler received unsupported payload".to_string(),
+                ));
+            }
+        };
+
+        let args: GrepFilesArgs = serde_json::from_str(&arguments).map_err(|err| {
+            FunctionCallError::RespondToModel(format!(
+                "failed to parse function arguments: {err:?}"
+            ))
+        })?;
+
+        let pattern = args.pattern.trim();
+        if pattern.is_empty() {
+            return Err(FunctionCallError::RespondToModel(
+                "pattern must not be empty".to_string(),
+            ));
+        }
+
+        if args.limit == 0 {
+            return Err(FunctionCallError::RespondToModel(
+                "limit must be greater than zero".to_string(),
+            ));
+        }
+
+        let limit = args.limit.min(MAX_LIMIT);
+        let search_path = turn.resolve_path(args.path.clone());
+
+        verify_path_exists(&search_path).await?;
+
+        let include = args.include.as_deref().map(str::trim).and_then(|val| {
+            if val.is_empty() {
+                None
+            } else {
+                Some(val.to_string())
+            }
+        });
+
+        let search_results =
+            run_rg_search(pattern, include.as_deref(), &search_path, limit, &turn.cwd).await?;
+
+        if search_results.is_empty() {
+            Ok(ToolOutput::Function {
+                content: "No matches found.".to_string(),
+                success: Some(false),
+            })
+        } else {
+            Ok(ToolOutput::Function {
+                content: search_results.join("\n"),
+                success: Some(true),
+            })
+        }
+    }
+}
+
+async fn verify_path_exists(path: &Path) -> Result<(), FunctionCallError> {
+    tokio::fs::metadata(path).await.map_err(|err| {
+        FunctionCallError::RespondToModel(format!("unable to access `{}`: {err}", path.display()))
+    })?;
+    Ok(())
+}
+
+async fn run_rg_search(
+    pattern: &str,
+    include: Option<&str>,
+    search_path: &Path,
+    limit: usize,
+    cwd: &Path,
+) -> Result<Vec<String>, FunctionCallError> {
+    let mut command = Command::new("rg");
+    command
+        .current_dir(cwd)
+        .arg("--files-with-matches")
+        .arg("--sortr=modified")
+        .arg("--regexp")
+        .arg(pattern)
+        .arg("--no-messages");
+
+    if let Some(glob) = include {
+        command.arg("--glob").arg(glob);
+    }
+
+    command.arg("--").arg(search_path);
+
+    let output = timeout(COMMAND_TIMEOUT, command.output())
+        .await
+        .map_err(|_| {
+            FunctionCallError::RespondToModel("rg timed out after 30 seconds".to_string())
+        })?
+        .map_err(|err| {
+            FunctionCallError::RespondToModel(format!(
+                "failed to launch rg: {err}. Ensure ripgrep is installed and on PATH."
+            ))
+        })?;
+
+    match output.status.code() {
+        Some(0) => Ok(parse_results(&output.stdout, limit)),
+        Some(1) => Ok(Vec::new()),
+        _ => {
+            let stderr = String::from_utf8_lossy(&output.stderr);
+            Err(FunctionCallError::RespondToModel(format!(
+                "rg failed: {stderr}"
+            )))
+        }
+    }
+}
+
+fn parse_results(stdout: &[u8], limit: usize) -> Vec<String> {
+    let mut results = Vec::new();
+    for line in stdout.split(|byte| *byte == b'\n') {
+        if line.is_empty() {
+            continue;
+        }
+        if let Ok(text) = std::str::from_utf8(line) {
+            if text.is_empty() {
+                continue;
+            }
+            results.push(text.to_string());
+            if results.len() == limit {
+                break;
+            }
+        }
+    }
+    results
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::process::Command as StdCommand;
+    use tempfile::tempdir;
+
+    #[test]
+    fn parses_basic_results() {
+        let stdout = b"/tmp/file_a.rs\n/tmp/file_b.rs\n";
+        let parsed = parse_results(stdout, 10);
+        assert_eq!(
+            parsed,
+            vec!["/tmp/file_a.rs".to_string(), "/tmp/file_b.rs".to_string()]
+        );
+    }
+
+    #[test]
+    fn parse_truncates_after_limit() {
+        let stdout = b"/tmp/file_a.rs\n/tmp/file_b.rs\n/tmp/file_c.rs\n";
+        let parsed = parse_results(stdout, 2);
+        assert_eq!(
+            parsed,
+            vec!["/tmp/file_a.rs".to_string(), "/tmp/file_b.rs".to_string()]
+        );
+    }
+
+    #[tokio::test]
+    async fn run_search_returns_results() -> anyhow::Result<()> {
+        if !rg_available() {
+            return Ok(());
+        }
+        let temp = tempdir().expect("create temp dir");
+        let dir = temp.path();
+        std::fs::write(dir.join("match_one.txt"), "alpha beta gamma").unwrap();
+        std::fs::write(dir.join("match_two.txt"), "alpha delta").unwrap();
+        std::fs::write(dir.join("other.txt"), "omega").unwrap();
+
+        let results = run_rg_search("alpha", None, dir, 10, dir).await?;
+        assert_eq!(results.len(), 2);
+        assert!(results.iter().any(|path| path.ends_with("match_one.txt")));
+        assert!(results.iter().any(|path| path.ends_with("match_two.txt")));
+        Ok(())
+    }
+
+    #[tokio::test]
+    async fn run_search_with_glob_filter() -> anyhow::Result<()> {
+        if !rg_available() {
+            return Ok(());
+        }
+        let temp = tempdir().expect("create temp dir");
+        let dir = temp.path();
+        std::fs::write(dir.join("match_one.rs"), "alpha beta gamma").unwrap();
+        std::fs::write(dir.join("match_two.txt"), "alpha delta").unwrap();
+
+        let results = run_rg_search("alpha", Some("*.rs"), dir, 10, dir).await?;
+        assert_eq!(results.len(), 1);
+        assert!(results.iter().all(|path| path.ends_with("match_one.rs")));
+        Ok(())
+    }
+
+    #[tokio::test]
+    async fn run_search_respects_limit() -> anyhow::Result<()> {
+        if !rg_available() {
+            return Ok(());
+        }
+        let temp = tempdir().expect("create temp dir");
+        let dir = temp.path();
+        std::fs::write(dir.join("one.txt"), "alpha one").unwrap();
+        std::fs::write(dir.join("two.txt"), "alpha two").unwrap();
+        std::fs::write(dir.join("three.txt"), "alpha three").unwrap();
+
+        let results = run_rg_search("alpha", None, dir, 2, dir).await?;
+        assert_eq!(results.len(), 2);
+        Ok(())
+    }
+
+    #[tokio::test]
+    async fn run_search_handles_no_matches() -> anyhow::Result<()> {
+        if !rg_available() {
+            return Ok(());
+        }
+        let temp = tempdir().expect("create temp dir");
+        let dir = temp.path();
+        std::fs::write(dir.join("one.txt"), "omega").unwrap();
+
+        let results = run_rg_search("alpha", None, dir, 5, dir).await?;
+        assert!(results.is_empty());
+        Ok(())
+    }
+
+    fn rg_available() -> bool {
+        StdCommand::new("rg")
+            .arg("--version")
+            .output()
+            .map(|output| output.status.success())
+            .unwrap_or(false)
+    }
+}

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

@@ -1,5 +1,6 @@
 pub mod apply_patch;
 mod exec_stream;
+mod grep_files;
 mod list_dir;
 mod mcp;
 mod plan;
@@ -13,6 +14,7 @@ pub use plan::PLAN_TOOL;
 
 pub use apply_patch::ApplyPatchHandler;
 pub use exec_stream::ExecStreamHandler;
+pub use grep_files::GrepFilesHandler;
 pub use list_dir::ListDirHandler;
 pub use mcp::McpHandler;
 pub use plan::PlanHandler;

codex-rs/core/src/tools/spec.rs

@@ -320,6 +320,56 @@ fn create_test_sync_tool() -> ToolSpec {
     })
 }
 
+fn create_grep_files_tool() -> ToolSpec {
+    let mut properties = BTreeMap::new();
+    properties.insert(
+        "pattern".to_string(),
+        JsonSchema::String {
+            description: Some("Regular expression pattern to search for.".to_string()),
+        },
+    );
+    properties.insert(
+        "include".to_string(),
+        JsonSchema::String {
+            description: Some(
+                "Optional glob that limits which files are searched (e.g. \"*.rs\" or \
+                 \"*.{ts,tsx}\")."
+                    .to_string(),
+            ),
+        },
+    );
+    properties.insert(
+        "path".to_string(),
+        JsonSchema::String {
+            description: Some(
+                "Directory or file path to search. Defaults to the session's working directory."
+                    .to_string(),
+            ),
+        },
+    );
+    properties.insert(
+        "limit".to_string(),
+        JsonSchema::Number {
+            description: Some(
+                "Maximum number of file paths to return (defaults to 100).".to_string(),
+            ),
+        },
+    );
+
+    ToolSpec::Function(ResponsesApiTool {
+        name: "grep_files".to_string(),
+        description: "Finds files whose contents match the pattern and lists them by modification \
+                      time."
+            .to_string(),
+        strict: false,
+        parameters: JsonSchema::Object {
+            properties,
+            required: Some(vec!["pattern".to_string()]),
+            additional_properties: Some(false.into()),
+        },
+    })
+}
+
 fn create_read_file_tool() -> ToolSpec {
     let mut properties = BTreeMap::new();
     properties.insert(
@@ -610,6 +660,7 @@ pub(crate) fn build_specs(
     use crate::exec_command::create_write_stdin_tool_for_responses_api;
     use crate::tools::handlers::ApplyPatchHandler;
     use crate::tools::handlers::ExecStreamHandler;
+    use crate::tools::handlers::GrepFilesHandler;
     use crate::tools::handlers::ListDirHandler;
     use crate::tools::handlers::McpHandler;
     use crate::tools::handlers::PlanHandler;
@@ -678,8 +729,16 @@ pub(crate) fn build_specs(
 
     if config
         .experimental_supported_tools
-        .iter()
-        .any(|tool| tool == "read_file")
+        .contains(&"grep_files".to_string())
+    {
+        let grep_files_handler = Arc::new(GrepFilesHandler);
+        builder.push_spec_with_parallel_support(create_grep_files_tool(), true);
+        builder.register_handler("grep_files", grep_files_handler);
+    }
+
+    if config
+        .experimental_supported_tools
+        .contains(&"read_file".to_string())
     {
         let read_file_handler = Arc::new(ReadFileHandler);
         builder.push_spec_with_parallel_support(create_read_file_tool(), true);
@@ -698,8 +757,7 @@ pub(crate) fn build_specs(
 
     if config
         .experimental_supported_tools
-        .iter()
-        .any(|tool| tool == "test_sync_tool")
+        .contains(&"test_sync_tool".to_string())
     {
         let test_sync_handler = Arc::new(TestSyncHandler);
         builder.push_spec_with_parallel_support(create_test_sync_tool(), true);
@@ -841,8 +899,9 @@ mod tests {
         let (tools, _) = build_specs(&config, None).build();
 
         assert!(!find_tool(&tools, "unified_exec").supports_parallel_tool_calls);
-        assert!(find_tool(&tools, "read_file").supports_parallel_tool_calls);
+        assert!(find_tool(&tools, "grep_files").supports_parallel_tool_calls);
         assert!(find_tool(&tools, "list_dir").supports_parallel_tool_calls);
+        assert!(find_tool(&tools, "read_file").supports_parallel_tool_calls);
     }
 
     #[test]
@@ -870,6 +929,11 @@ mod tests {
                 .iter()
                 .any(|tool| tool_name(&tool.spec) == "read_file")
         );
+        assert!(
+            tools
+                .iter()
+                .any(|tool| tool_name(&tool.spec) == "grep_files")
+        );
         assert!(tools.iter().any(|tool| tool_name(&tool.spec) == "list_dir"));
     }
 

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

@@ -0,0 +1,237 @@
+#![cfg(not(target_os = "windows"))]
+
+use anyhow::Result;
+use codex_core::model_family::find_family_for_model;
+use codex_core::protocol::AskForApproval;
+use codex_core::protocol::EventMsg;
+use codex_core::protocol::InputItem;
+use codex_core::protocol::Op;
+use codex_core::protocol::SandboxPolicy;
+use codex_protocol::config_types::ReasoningSummary;
+use core_test_support::responses;
+use core_test_support::responses::ev_assistant_message;
+use core_test_support::responses::ev_completed;
+use core_test_support::responses::ev_function_call;
+use core_test_support::responses::ev_response_created;
+use core_test_support::responses::sse;
+use core_test_support::responses::start_mock_server;
+use core_test_support::skip_if_no_network;
+use core_test_support::test_codex::TestCodex;
+use core_test_support::test_codex::test_codex;
+use core_test_support::wait_for_event;
+use serde_json::Value;
+use std::collections::HashSet;
+use std::path::Path;
+use std::process::Command as StdCommand;
+use wiremock::matchers::any;
+
+const MODEL_WITH_TOOL: &str = "test-gpt-5-codex";
+
+fn ripgrep_available() -> bool {
+    StdCommand::new("rg")
+        .arg("--version")
+        .output()
+        .map(|output| output.status.success())
+        .unwrap_or(false)
+}
+
+macro_rules! skip_if_ripgrep_missing {
+    ($ret:expr $(,)?) => {{
+        if !ripgrep_available() {
+            eprintln!("rg not available in PATH; skipping test");
+            return $ret;
+        }
+    }};
+}
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn grep_files_tool_collects_matches() -> Result<()> {
+    skip_if_no_network!(Ok(()));
+    skip_if_ripgrep_missing!(Ok(()));
+
+    let server = start_mock_server().await;
+    let test = build_test_codex(&server).await?;
+
+    let search_dir = test.cwd.path().join("src");
+    std::fs::create_dir_all(&search_dir)?;
+    let alpha = search_dir.join("alpha.rs");
+    let beta = search_dir.join("beta.rs");
+    let gamma = search_dir.join("gamma.txt");
+    std::fs::write(&alpha, "alpha needle\n")?;
+    std::fs::write(&beta, "beta needle\n")?;
+    std::fs::write(&gamma, "needle in text but excluded\n")?;
+
+    let call_id = "grep-files-collect";
+    let arguments = serde_json::json!({
+        "pattern": "needle",
+        "path": search_dir.to_string_lossy(),
+        "include": "*.rs",
+    })
+    .to_string();
+
+    mount_tool_sequence(&server, call_id, &arguments, "grep_files").await;
+    submit_turn(&test, "please find uses of needle").await?;
+
+    let bodies = recorded_bodies(&server).await?;
+    let tool_output = find_tool_output(&bodies, call_id).expect("tool output present");
+    let payload = tool_output.get("output").expect("output field present");
+    let (content_opt, success_opt) = extract_content_and_success(payload);
+    let content = content_opt.expect("content present");
+    let success = success_opt.unwrap_or(true);
+    assert!(success, "expected success for matches, got {payload:?}");
+
+    let entries = collect_file_names(content);
+    assert_eq!(entries.len(), 2, "content: {content}");
+    assert!(
+        entries.contains("alpha.rs"),
+        "missing alpha.rs in {entries:?}"
+    );
+    assert!(
+        entries.contains("beta.rs"),
+        "missing beta.rs in {entries:?}"
+    );
+    assert!(
+        !entries.contains("gamma.txt"),
+        "txt file should be filtered out: {entries:?}"
+    );
+
+    Ok(())
+}
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn grep_files_tool_reports_empty_results() -> Result<()> {
+    skip_if_no_network!(Ok(()));
+    skip_if_ripgrep_missing!(Ok(()));
+
+    let server = start_mock_server().await;
+    let test = build_test_codex(&server).await?;
+
+    let search_dir = test.cwd.path().join("logs");
+    std::fs::create_dir_all(&search_dir)?;
+    std::fs::write(search_dir.join("output.txt"), "no hits here")?;
+
+    let call_id = "grep-files-empty";
+    let arguments = serde_json::json!({
+        "pattern": "needle",
+        "path": search_dir.to_string_lossy(),
+        "limit": 5,
+    })
+    .to_string();
+
+    mount_tool_sequence(&server, call_id, &arguments, "grep_files").await;
+    submit_turn(&test, "search again").await?;
+
+    let bodies = recorded_bodies(&server).await?;
+    let tool_output = find_tool_output(&bodies, call_id).expect("tool output present");
+    let payload = tool_output.get("output").expect("output field present");
+    let (content_opt, success_opt) = extract_content_and_success(payload);
+    let content = content_opt.expect("content present");
+    if let Some(success) = success_opt {
+        assert!(!success, "expected success=false payload: {payload:?}");
+    }
+    assert_eq!(content, "No matches found.");
+
+    Ok(())
+}
+
+#[allow(clippy::expect_used)]
+async fn build_test_codex(server: &wiremock::MockServer) -> Result<TestCodex> {
+    let mut builder = test_codex().with_config(|config| {
+        config.model = MODEL_WITH_TOOL.to_string();
+        config.model_family =
+            find_family_for_model(MODEL_WITH_TOOL).expect("model family for test model");
+    });
+    builder.build(server).await
+}
+
+async fn submit_turn(test: &TestCodex, prompt: &str) -> Result<()> {
+    let session_model = test.session_configured.model.clone();
+
+    test.codex
+        .submit(Op::UserTurn {
+            items: vec![InputItem::Text {
+                text: prompt.into(),
+            }],
+            final_output_json_schema: None,
+            cwd: test.cwd.path().to_path_buf(),
+            approval_policy: AskForApproval::Never,
+            sandbox_policy: SandboxPolicy::DangerFullAccess,
+            model: session_model,
+            effort: None,
+            summary: ReasoningSummary::Auto,
+        })
+        .await?;
+
+    wait_for_event(&test.codex, |event| {
+        matches!(event, EventMsg::TaskComplete(_))
+    })
+    .await;
+    Ok(())
+}
+
+async fn mount_tool_sequence(
+    server: &wiremock::MockServer,
+    call_id: &str,
+    arguments: &str,
+    tool_name: &str,
+) {
+    let first_response = sse(vec![
+        ev_response_created("resp-1"),
+        ev_function_call(call_id, tool_name, arguments),
+        ev_completed("resp-1"),
+    ]);
+    responses::mount_sse_once_match(server, any(), first_response).await;
+
+    let second_response = sse(vec![
+        ev_assistant_message("msg-1", "done"),
+        ev_completed("resp-2"),
+    ]);
+    responses::mount_sse_once_match(server, any(), second_response).await;
+}
+
+#[allow(clippy::expect_used)]
+async fn recorded_bodies(server: &wiremock::MockServer) -> Result<Vec<Value>> {
+    let requests = server.received_requests().await.expect("requests recorded");
+    Ok(requests
+        .iter()
+        .map(|req| req.body_json::<Value>().expect("request json"))
+        .collect())
+}
+
+fn find_tool_output<'a>(requests: &'a [Value], call_id: &str) -> Option<&'a Value> {
+    requests.iter().find_map(|body| {
+        body.get("input")
+            .and_then(Value::as_array)
+            .and_then(|items| {
+                items.iter().find(|item| {
+                    item.get("type").and_then(Value::as_str) == Some("function_call_output")
+                        && item.get("call_id").and_then(Value::as_str) == Some(call_id)
+                })
+            })
+    })
+}
+
+fn collect_file_names(content: &str) -> HashSet<String> {
+    content
+        .lines()
+        .filter_map(|line| {
+            if line.trim().is_empty() {
+                return None;
+            }
+            Path::new(line)
+                .file_name()
+                .map(|name| name.to_string_lossy().into_owned())
+        })
+        .collect()
+}
+
+fn extract_content_and_success(value: &Value) -> (Option<&str>, Option<bool>) {
+    match value {
+        Value::String(text) => (Some(text.as_str()), None),
+        Value::Object(obj) => (
+            obj.get("content").and_then(Value::as_str),
+            obj.get("success").and_then(Value::as_bool),
+        ),
+        _ => (None, None),
+    }
+}

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

@@ -9,6 +9,7 @@ mod compact_resume_fork;
 mod exec;
 mod exec_stream_events;
 mod fork_conversation;
+mod grep_files;
 mod json_result;
 mod list_dir;
 mod live_cli;

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

@@ -63,8 +63,9 @@ async fn build_codex_with_test_tool(server: &wiremock::MockServer) -> anyhow::Re
 }
 
 fn assert_parallel_duration(actual: Duration) {
+    // Allow headroom for runtime overhead while still differentiating from serial execution.
     assert!(
-        actual < Duration::from_millis(500),
+        actual < Duration::from_millis(750),
         "expected parallel execution to finish quickly, got {actual:?}"
     );
 }