agent: Use current shell (#28470)

Release Notes:

- agent: Replace `bash` tool with `terminal` tool which uses the current
shell

---------

Co-authored-by: Bennet <bennet@zed.dev>
Co-authored-by: Antonio <antonio@zed.dev>

assets/prompts/assistant_system_prompt.hbs

@@ -163,3 +163,8 @@ There are rules that apply to these root directories:
 {{/if}}
 {{/each}}
 {{/if}}
+
+<user_environment>
+Operating System: {{os}} ({{arch}})
+Shell: {{shell}}
+</user_environment>

assets/settings/default.json

@@ -656,7 +656,7 @@
         "name": "Write",
         "enable_all_context_servers": true,
         "tools": {
-          "bash": true,
+          "terminal": true,
           "batch_tool": true,
           "code_actions": true,
           "code_symbols": true,

crates/assistant_tools/src/assistant_tools.rs

@@ -1,4 +1,3 @@
-mod bash_tool;
 mod batch_tool;
 mod code_action_tool;
 mod code_symbols_tool;
@@ -20,6 +19,7 @@ mod rename_tool;
 mod replace;
 mod schema;
 mod symbol_info_tool;
+mod terminal_tool;
 mod thinking_tool;
 
 use std::sync::Arc;
@@ -30,7 +30,6 @@ use gpui::App;
 use http_client::HttpClientWithUrl;
 use move_path_tool::MovePathTool;
 
-use crate::bash_tool::BashTool;
 use crate::batch_tool::BatchTool;
 use crate::code_action_tool::CodeActionTool;
 use crate::code_symbols_tool::CodeSymbolsTool;
@@ -48,13 +47,14 @@ use crate::read_file_tool::ReadFileTool;
 use crate::regex_search_tool::RegexSearchTool;
 use crate::rename_tool::RenameTool;
 use crate::symbol_info_tool::SymbolInfoTool;
+use crate::terminal_tool::TerminalTool;
 use crate::thinking_tool::ThinkingTool;
 
 pub fn init(http_client: Arc<HttpClientWithUrl>, cx: &mut App) {
     assistant_tool::init(cx);
 
     let registry = ToolRegistry::global(cx);
-    registry.register_tool(BashTool);
+    registry.register_tool(TerminalTool);
     registry.register_tool(BatchTool);
     registry.register_tool(CreateDirectoryTool);
     registry.register_tool(CreateFileTool);

crates/assistant_tools/src/bash_tool/description.md

@@ -1,7 +0,0 @@
-Executes a bash one-liner and returns the combined output.
-
-This tool spawns a bash process, combines stdout and stderr into one interleaved stream as they are produced (preserving the order of writes), and captures that stream into a string which is returned.
-
-Make sure you use the `cd` parameter to navigate to one of the root directories of the project. NEVER do it as part of the `command` itself, otherwise it will error.
-
-Remember that each invocation of this tool will spawn a new bash process, so you can't rely on any state from previous invocations.

crates/assistant_tools/src/terminal_tool.rs

@@ -2,12 +2,15 @@ use crate::schema::json_schema_for;
 use anyhow::{Context as _, Result, anyhow};
 use assistant_tool::{ActionLog, Tool};
 use futures::io::BufReader;
-use futures::{AsyncBufReadExt, AsyncReadExt};
+use futures::{AsyncBufReadExt, AsyncReadExt, FutureExt};
 use gpui::{App, AppContext, Entity, Task};
 use language_model::{LanguageModelRequestMessage, LanguageModelToolSchemaFormat};
 use project::Project;
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
+use std::future;
+use util::get_system_shell;
+
 use std::path::Path;
 use std::sync::Arc;
 use ui::IconName;
@@ -15,18 +18,18 @@ use util::command::new_smol_command;
 use util::markdown::MarkdownString;
 
 #[derive(Debug, Serialize, Deserialize, JsonSchema)]
-pub struct BashToolInput {
-    /// The bash one-liner command to execute.
+pub struct TerminalToolInput {
+    /// The one-liner command to execute.
     command: String,
     /// Working directory for the command. This must be one of the root directories of the project.
     cd: String,
 }
 
-pub struct BashTool;
+pub struct TerminalTool;
 
-impl Tool for BashTool {
+impl Tool for TerminalTool {
     fn name(&self) -> String {
-        "bash".to_string()
+        "terminal".to_string()
     }
 
     fn needs_confirmation(&self, _: &serde_json::Value, _: &App) -> bool {
@@ -34,7 +37,7 @@ impl Tool for BashTool {
     }
 
     fn description(&self) -> String {
-        include_str!("./bash_tool/description.md").to_string()
+        include_str!("./terminal_tool/description.md").to_string()
     }
 
     fn icon(&self) -> IconName {
@@ -42,11 +45,11 @@ impl Tool for BashTool {
     }
 
     fn input_schema(&self, format: LanguageModelToolSchemaFormat) -> serde_json::Value {
-        json_schema_for::<BashToolInput>(format)
+        json_schema_for::<TerminalToolInput>(format)
     }
 
     fn ui_text(&self, input: &serde_json::Value) -> String {
-        match serde_json::from_value::<BashToolInput>(input.clone()) {
+        match serde_json::from_value::<TerminalToolInput>(input.clone()) {
             Ok(input) => {
                 let mut lines = input.command.lines();
                 let first_line = lines.next().unwrap_or_default();
@@ -65,7 +68,7 @@ impl Tool for BashTool {
                     }
                 }
             }
-            Err(_) => "Run bash command".to_string(),
+            Err(_) => "Run terminal command".to_string(),
         }
     }
 
@@ -77,7 +80,7 @@ impl Tool for BashTool {
         _action_log: Entity<ActionLog>,
         cx: &mut App,
     ) -> Task<Result<String>> {
-        let input: BashToolInput = match serde_json::from_value(input) {
+        let input: TerminalToolInput = match serde_json::from_value(input) {
             Ok(input) => input,
             Err(err) => return Task::ready(Err(anyhow!(err))),
         };
@@ -130,67 +133,87 @@ impl Tool for BashTool {
 const LIMIT: usize = 16 * 1024;
 
 async fn run_command_limited(working_dir: Arc<Path>, command: String) -> Result<String> {
-    // Add 2>&1 to merge stderr into stdout for proper interleaving.
-    let command = format!("({}) 2>&1", command);
+    let shell = get_system_shell();
 
-    let mut cmd = new_smol_command("bash")
+    let mut cmd = new_smol_command(&shell)
         .arg("-c")
         .arg(&command)
         .current_dir(working_dir)
         .stdout(std::process::Stdio::piped())
+        .stderr(std::process::Stdio::piped())
         .spawn()
-        .context("Failed to execute bash command")?;
+        .context("Failed to execute terminal command")?;
 
-    // Capture stdout with a limit
-    let stdout = cmd.stdout.take().unwrap();
-    let mut reader = BufReader::new(stdout);
+    let mut combined_buffer = String::with_capacity(LIMIT + 1);
 
-    // Read one more byte to determine whether the output was truncated
-    let mut buffer = vec![0; LIMIT + 1];
-    let mut bytes_read = 0;
+    let mut out_reader = BufReader::new(cmd.stdout.take().context("Failed to get stdout")?);
+    let mut out_tmp_buffer = String::with_capacity(512);
+    let mut err_reader = BufReader::new(cmd.stderr.take().context("Failed to get stderr")?);
+    let mut err_tmp_buffer = String::with_capacity(512);
 
-    // Read until we reach the limit
-    loop {
-        let read = reader.read(&mut buffer[bytes_read..]).await?;
-        if read == 0 {
-            break;
-        }
+    let mut out_line = Box::pin(
+        out_reader
+            .read_line(&mut out_tmp_buffer)
+            .left_future()
+            .fuse(),
+    );
+    let mut err_line = Box::pin(
+        err_reader
+            .read_line(&mut err_tmp_buffer)
+            .left_future()
+            .fuse(),
+    );
 
-        bytes_read += read;
-        if bytes_read > LIMIT {
-            bytes_read = LIMIT + 1;
-            break;
-        }
+    let mut has_stdout = true;
+    let mut has_stderr = true;
+    while (has_stdout || has_stderr) && combined_buffer.len() < LIMIT + 1 {
+        futures::select_biased! {
+            read = out_line => {
+                drop(out_line);
+                combined_buffer.extend(out_tmp_buffer.drain(..));
+                if read? == 0 {
+                    out_line = Box::pin(future::pending().right_future().fuse());
+                    has_stdout = false;
+                } else {
+                    out_line = Box::pin(out_reader.read_line(&mut out_tmp_buffer).left_future().fuse());
+                }
+            }
+            read = err_line => {
+                drop(err_line);
+                combined_buffer.extend(err_tmp_buffer.drain(..));
+                if read? == 0 {
+                    err_line = Box::pin(future::pending().right_future().fuse());
+                    has_stderr = false;
+                } else {
+                    err_line = Box::pin(err_reader.read_line(&mut err_tmp_buffer).left_future().fuse());
+                }
+            }
+        };
     }
 
-    // Repeatedly fill the output reader's buffer without copying it.
-    loop {
-        let skipped_bytes = reader.fill_buf().await?;
-        if skipped_bytes.is_empty() {
-            break;
-        }
-        let skipped_bytes_len = skipped_bytes.len();
-        reader.consume_unpin(skipped_bytes_len);
-    }
+    drop((out_line, err_line));
 
-    let output_bytes = &buffer[..bytes_read.min(LIMIT)];
+    let truncated = combined_buffer.len() > LIMIT;
+    combined_buffer.truncate(LIMIT);
+
+    consume_reader(out_reader, truncated).await?;
+    consume_reader(err_reader, truncated).await?;
 
     let status = cmd.status().await.context("Failed to get command status")?;
 
-    let output_string = if bytes_read > LIMIT {
+    let output_string = if truncated {
         // Valid to find `\n` in UTF-8 since 0-127 ASCII characters are not used in
         // multi-byte characters.
-        let last_line_ix = output_bytes.iter().rposition(|b| *b == b'\n');
-        let until_last_line = &output_bytes[..last_line_ix.unwrap_or(output_bytes.len())];
-        let output_string = String::from_utf8_lossy(until_last_line);
+        let last_line_ix = combined_buffer.bytes().rposition(|b| b == b'\n');
+        let combined_buffer = &combined_buffer[..last_line_ix.unwrap_or(combined_buffer.len())];
 
         format!(
             "Command output too long. The first {} bytes:\n\n{}",
-            output_string.len(),
-            output_block(&output_string),
+            combined_buffer.len(),
+            output_block(&combined_buffer),
         )
     } else {
-        output_block(&String::from_utf8_lossy(&output_bytes))
+        output_block(&combined_buffer)
     };
 
     let output_with_status = if status.success() {
@@ -201,8 +224,9 @@ async fn run_command_limited(working_dir: Arc<Path>, command: String) -> Result<
         }
     } else {
         format!(
-            "Command failed with exit code {}\n\n{}",
+            "Command failed with exit code {} (shell: {}).\n\n{}",
             status.code().unwrap_or(-1),
+            shell,
             output_string,
         )
     };
@@ -210,6 +234,24 @@ async fn run_command_limited(working_dir: Arc<Path>, command: String) -> Result<
     Ok(output_with_status)
 }
 
+async fn consume_reader<T: AsyncReadExt + Unpin>(
+    mut reader: BufReader<T>,
+    truncated: bool,
+) -> Result<(), std::io::Error> {
+    loop {
+        let skipped_bytes = reader.fill_buf().await?;
+        if skipped_bytes.is_empty() {
+            break;
+        }
+        let skipped_bytes_len = skipped_bytes.len();
+        reader.consume_unpin(skipped_bytes_len);
+
+        // Should only skip if we went over the limit
+        debug_assert!(truncated);
+    }
+    Ok(())
+}
+
 fn output_block(output: &str) -> String {
     format!(
         "```\n{}{}```",
@@ -225,7 +267,7 @@ mod tests {
 
     use super::*;
 
-    #[gpui::test]
+    #[gpui::test(iterations = 10)]
     async fn test_run_command_simple(cx: &mut TestAppContext) {
         cx.executor().allow_parking();
 
@@ -236,12 +278,11 @@ mod tests {
         assert_eq!(result.unwrap(), "```\nHello, World!\n```");
     }
 
-    #[gpui::test]
+    #[gpui::test(iterations = 10)]
     async fn test_interleaved_stdout_stderr(cx: &mut TestAppContext) {
         cx.executor().allow_parking();
 
-        let command =
-            "echo 'stdout 1' && echo 'stderr 1' >&2 && echo 'stdout 2' && echo 'stderr 2' >&2";
+        let command = "echo 'stdout 1' && sleep 0.01 && echo 'stderr 1' >&2 && sleep 0.01 && echo 'stdout 2' && sleep 0.01 && echo 'stderr 2' >&2";
         let result = run_command_limited(Path::new(".").into(), command.to_string()).await;
 
         assert!(result.is_ok());
@@ -251,7 +292,7 @@ mod tests {
         );
     }
 
-    #[gpui::test]
+    #[gpui::test(iterations = 10)]
     async fn test_multiple_output_reads(cx: &mut TestAppContext) {
         cx.executor().allow_parking();
 
@@ -266,11 +307,11 @@ mod tests {
         assert_eq!(result.unwrap(), "```\n1\n2\n3\n```");
     }
 
-    #[gpui::test]
+    #[gpui::test(iterations = 10)]
     async fn test_output_truncation_single_line(cx: &mut TestAppContext) {
         cx.executor().allow_parking();
 
-        let cmd = format!("echo '{}';", "X".repeat(LIMIT * 2));
+        let cmd = format!("echo '{}'; sleep 0.01;", "X".repeat(LIMIT * 2));
 
         let result = run_command_limited(Path::new(".").into(), cmd).await;
 
@@ -285,7 +326,7 @@ mod tests {
         assert_eq!(content_length, LIMIT);
     }
 
-    #[gpui::test]
+    #[gpui::test(iterations = 10)]
     async fn test_output_truncation_multiline(cx: &mut TestAppContext) {
         cx.executor().allow_parking();
 
@@ -303,4 +344,23 @@ mod tests {
 
         assert!(content_length <= LIMIT);
     }
+
+    #[gpui::test(iterations = 10)]
+    async fn test_command_failure(cx: &mut TestAppContext) {
+        cx.executor().allow_parking();
+
+        let result = run_command_limited(Path::new(".").into(), "exit 42".to_string()).await;
+
+        assert!(result.is_ok());
+        let output = result.unwrap();
+
+        // Extract the shell name from path for cleaner test output
+        let shell_path = std::env::var("SHELL").unwrap_or("bash".to_string());
+
+        let expected_output = format!(
+            "Command failed with exit code 42 (shell: {}).\n\n```\n\n```",
+            shell_path
+        );
+        assert_eq!(output, expected_output);
+    }
 }

crates/assistant_tools/src/terminal_tool/description.md

@@ -0,0 +1,9 @@
+Executes a shell one-liner and returns the combined output.
+
+This tool spawns a process using the user's current shell, combines stdout and stderr into one interleaved stream as they are produced (preserving the order of writes), and captures that stream into a string which is returned.
+
+Make sure you use the `cd` parameter to navigate to one of the root directories of the project. NEVER do it as part of the `command` itself, otherwise it will error.
+
+Do not use this tool for commands that run indefinitely, such as servers (e.g., `python -m http.server`) or file watchers that don't terminate on their own.
+
+Remember that each invocation of this tool will spawn a new shell process, so you can't rely on any state from previous invocations.

crates/migrator/src/migrations.rs

@@ -37,3 +37,9 @@ pub(crate) mod m_2025_03_29 {
 
     pub(crate) use settings::SETTINGS_PATTERNS;
 }
+
+pub(crate) mod m_2025_04_15 {
+    mod settings;
+
+    pub(crate) use settings::SETTINGS_PATTERNS;
+}

crates/migrator/src/migrations/m_2025_04_15/settings.rs

@@ -0,0 +1,29 @@
+use std::ops::Range;
+use tree_sitter::{Query, QueryMatch};
+
+use crate::MigrationPatterns;
+use crate::patterns::SETTINGS_ASSISTANT_TOOLS_PATTERN;
+
+pub const SETTINGS_PATTERNS: MigrationPatterns = &[(
+    SETTINGS_ASSISTANT_TOOLS_PATTERN,
+    replace_bash_with_terminal_in_profiles,
+)];
+
+fn replace_bash_with_terminal_in_profiles(
+    contents: &str,
+    mat: &QueryMatch,
+    query: &Query,
+) -> Option<(Range<usize>, String)> {
+    let tool_name_capture_ix = query.capture_index_for_name("tool_name")?;
+    let tool_name_range = mat
+        .nodes_for_capture_index(tool_name_capture_ix)
+        .next()?
+        .byte_range();
+    let tool_name = contents.get(tool_name_range.clone())?;
+
+    if tool_name != "bash" {
+        return None;
+    }
+
+    Some((tool_name_range, "terminal".to_string()))
+}

crates/migrator/src/migrator.rs

@@ -120,6 +120,10 @@ pub fn migrate_settings(text: &str) -> Result<Option<String>> {
             migrations::m_2025_03_29::SETTINGS_PATTERNS,
             &SETTINGS_QUERY_2025_03_29,
         ),
+        (
+            migrations::m_2025_04_15::SETTINGS_PATTERNS,
+            &SETTINGS_QUERY_2025_04_15,
+        ),
     ];
     run_migrations(text, migrations)
 }
@@ -190,6 +194,10 @@ define_query!(
     SETTINGS_QUERY_2025_03_29,
     migrations::m_2025_03_29::SETTINGS_PATTERNS
 );
+define_query!(
+    SETTINGS_QUERY_2025_04_15,
+    migrations::m_2025_04_15::SETTINGS_PATTERNS
+);
 
 // custom query
 static EDIT_PREDICTION_SETTINGS_MIGRATION_QUERY: LazyLock<Query> = LazyLock::new(|| {
@@ -527,4 +535,103 @@ mod tests {
             ),
         )
     }
+
+    #[test]
+    fn test_replace_bash_with_terminal_in_profiles() {
+        assert_migrate_settings(
+            r#"
+                {
+                    "assistant": {
+                        "profiles": {
+                            "custom": {
+                                "name": "Custom",
+                                "tools": {
+                                    "bash": true,
+                                    "diagnostics": true
+                                }
+                            }
+                        }
+                    }
+                }
+            "#,
+            Some(
+                r#"
+                {
+                    "assistant": {
+                        "profiles": {
+                            "custom": {
+                                "name": "Custom",
+                                "tools": {
+                                    "terminal": true,
+                                    "diagnostics": true
+                                }
+                            }
+                        }
+                    }
+                }
+            "#,
+            ),
+        )
+    }
+
+    #[test]
+    fn test_replace_bash_false_with_terminal_in_profiles() {
+        assert_migrate_settings(
+            r#"
+                {
+                    "assistant": {
+                        "profiles": {
+                            "custom": {
+                                "name": "Custom",
+                                "tools": {
+                                    "bash": false,
+                                    "diagnostics": true
+                                }
+                            }
+                        }
+                    }
+                }
+            "#,
+            Some(
+                r#"
+                {
+                    "assistant": {
+                        "profiles": {
+                            "custom": {
+                                "name": "Custom",
+                                "tools": {
+                                    "terminal": false,
+                                    "diagnostics": true
+                                }
+                            }
+                        }
+                    }
+                }
+            "#,
+            ),
+        )
+    }
+
+    #[test]
+    fn test_no_bash_in_profiles() {
+        assert_migrate_settings(
+            r#"
+                {
+                    "assistant": {
+                        "profiles": {
+                            "custom": {
+                                "name": "Custom",
+                                "tools": {
+                                    "diagnostics": true,
+                                    "path_search": true,
+                                    "read_file": true
+                                }
+                            }
+                        }
+                    }
+                }
+            "#,
+            None,
+        )
+    }
 }

crates/migrator/src/patterns.rs

@@ -7,5 +7,6 @@ pub(crate) use keymap::{
 };
 
 pub(crate) use settings::{
-    SETTINGS_LANGUAGES_PATTERN, SETTINGS_NESTED_KEY_VALUE_PATTERN, SETTINGS_ROOT_KEY_VALUE_PATTERN,
+    SETTINGS_ASSISTANT_TOOLS_PATTERN, SETTINGS_LANGUAGES_PATTERN,
+    SETTINGS_NESTED_KEY_VALUE_PATTERN, SETTINGS_ROOT_KEY_VALUE_PATTERN,
 };

crates/migrator/src/patterns/settings.rs

@@ -39,3 +39,35 @@ pub const SETTINGS_LANGUAGES_PATTERN: &str = r#"(document
     )
     (#eq? @languages "languages")
 )"#;
+
+pub const SETTINGS_ASSISTANT_TOOLS_PATTERN: &str = r#"(document
+    (object
+        (pair
+            key: (string (string_content) @assistant)
+            value: (object
+                (pair
+                    key: (string (string_content) @profiles)
+                    value: (object
+                        (pair
+                            key: (_)
+                            value: (object
+                                (pair
+                                    key: (string (string_content) @tools_key)
+                                    value: (object
+                                        (pair
+                                            key: (string (string_content) @tool_name)
+                                            value: (_) @tool_value
+                                        )
+                                    )
+                                )
+                            )
+                        )
+                    )
+                )
+            )
+        )
+    )
+    (#eq? @assistant "assistant")
+    (#eq? @profiles "profiles")
+    (#eq? @tools_key "tools")
+)"#;

crates/prompt_store/src/prompts.rs

@@ -14,12 +14,15 @@ use std::{
     time::Duration,
 };
 use text::LineEnding;
-use util::ResultExt;
+use util::{ResultExt, get_system_shell};
 
 #[derive(Serialize)]
 pub struct AssistantSystemPromptContext {
     pub worktrees: Vec<WorktreeInfoForSystemPrompt>,
     pub has_rules: bool,
+    pub os: String,
+    pub arch: String,
+    pub shell: String,
 }
 
 impl AssistantSystemPromptContext {
@@ -30,6 +33,9 @@ impl AssistantSystemPromptContext {
         Self {
             worktrees,
             has_rules,
+            os: std::env::consts::OS.to_string(),
+            arch: std::env::consts::ARCH.to_string(),
+            shell: get_system_shell(),
         }
     }
 }

crates/task/src/lib.rs

@@ -467,7 +467,7 @@ impl ShellBuilder {
 
     // `alacritty_terminal` uses this as default on Windows. See:
     // https://github.com/alacritty/alacritty/blob/0d4ab7bca43213d96ddfe40048fc0f922543c6f8/alacritty_terminal/src/tty/windows/mod.rs#L130
-    // We could use `util::retrieve_system_shell()` here, but we are running tasks here, so leave it to `powershell.exe`
+    // We could use `util::get_windows_system_shell()` here, but we are running tasks here, so leave it to `powershell.exe`
     // should be okay.
     fn system_shell() -> String {
         "powershell.exe".to_string()

crates/terminal/src/terminal.rs

@@ -380,7 +380,7 @@ impl TerminalBuilder {
                     #[cfg(target_os = "windows")]
                     {
                         Some(alacritty_terminal::tty::Shell::new(
-                            util::retrieve_system_shell(),
+                            util::get_windows_system_shell(),
                             Vec::new(),
                         ))
                     }

crates/util/src/util.rs

@@ -477,7 +477,7 @@ pub fn iterate_expanded_and_wrapped_usize_range(
 }
 
 #[cfg(target_os = "windows")]
-pub fn retrieve_system_shell() -> String {
+pub fn get_windows_system_shell() -> String {
     use std::path::PathBuf;
 
     fn find_pwsh_in_programfiles(find_alternate: bool, find_preview: bool) -> Option<PathBuf> {
@@ -994,6 +994,18 @@ pub fn default<D: Default>() -> D {
     Default::default()
 }
 
+pub fn get_system_shell() -> String {
+    #[cfg(target_os = "windows")]
+    {
+        get_windows_system_shell()
+    }
+
+    #[cfg(not(target_os = "windows"))]
+    {
+        std::env::var("SHELL").unwrap_or("/bin/sh".to_string())
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;