Inline assistant v2 (#21828)

This is behind the Assistant v2 feature flag. As @maxdeviant and I
discussed, the state is currently decoupled from the Assistant Panel's
state, although in the future we plan to introduce a way to refer to
conversations from the panel. Also, we're intentionally duplicating some
code with the v2 panel right now; the plan is to do a future PR to make
them share code more.


https://github.com/user-attachments/assets/bb163bd3-a02d-4a91-8f8f-2a8e60acbc34

It doesn't include the terminal inline assistant, which will be in a
separate PR.

Release Notes:

- N/A

crates/assistant2/Cargo.toml

@@ -13,30 +13,51 @@ path = "src/assistant.rs"
 doctest = false
 
 [dependencies]
+anthropic = { workspace = true, features = ["schemars"] }
 anyhow.workspace = true
+assets.workspace = true
 assistant_tool.workspace = true
-chrono.workspace = true
+async-watch.workspace = true
 client.workspace = true
+chrono.workspace = true
 collections.workspace = true
 command_palette_hooks.workspace = true
 context_server.workspace = true
+db.workspace = true
 editor.workspace = true
 feature_flags.workspace = true
+fs.workspace = true
 futures.workspace = true
 gpui.workspace = true
+handlebars.workspace = true
 language.workspace = true
 language_model.workspace = true
 language_model_selector.workspace = true
 language_models.workspace = true
 log.workspace = true
+lsp.workspace = true
 markdown.workspace = true
+menu.workspace = true
+multi_buffer.workspace = true
+ollama = { workspace = true, features = ["schemars"] }
+open_ai = { workspace = true, features = ["schemars"] }
+ordered-float.workspace = true
+paths.workspace = true
+parking_lot.workspace = true
 picker.workspace = true
 project.workspace = true
 proto.workspace = true
+rope.workspace = true
+schemars.workspace = true
 serde.workspace = true
 serde_json.workspace = true
+serde_json_lenient.workspace = true
 settings.workspace = true
+similar.workspace = true
 smol.workspace = true
+telemetry_events.workspace = true
+terminal_view.workspace = true
+text.workspace = true
 theme.workspace = true
 time.workspace = true
 time_format.workspace = true
@@ -45,3 +66,8 @@ unindent.workspace = true
 util.workspace = true
 uuid.workspace = true
 workspace.workspace = true
+zed_actions.workspace = true
+
+[dev-dependencies]
+rand.workspace = true
+indoc.workspace = true

crates/assistant2/src/assistant.rs

@@ -1,16 +1,28 @@
 mod active_thread;
 mod assistant_panel;
+mod assistant_settings;
 mod context;
 mod context_picker;
+mod inline_assistant;
 mod message_editor;
+mod prompts;
+mod streaming_diff;
 mod thread;
 mod thread_history;
 mod thread_store;
 mod ui;
 
+use std::sync::Arc;
+
+use assistant_settings::AssistantSettings;
+use client::Client;
 use command_palette_hooks::CommandPaletteFilter;
 use feature_flags::{Assistant2FeatureFlag, FeatureFlagAppExt};
+use fs::Fs;
 use gpui::{actions, AppContext};
+use prompts::PromptLoadingParams;
+use settings::Settings as _;
+use util::ResultExt;
 
 pub use crate::assistant_panel::AssistantPanel;
 
@@ -21,15 +33,37 @@ actions!(
         NewThread,
         ToggleModelSelector,
         OpenHistory,
-        Chat
+        Chat,
+        ToggleInlineAssist,
+        CycleNextInlineAssist,
+        CyclePreviousInlineAssist
     ]
 );
 
 const NAMESPACE: &str = "assistant2";
 
 /// Initializes the `assistant2` crate.
-pub fn init(cx: &mut AppContext) {
+pub fn init(fs: Arc<dyn Fs>, client: Arc<Client>, stdout_is_a_pty: bool, cx: &mut AppContext) {
+    AssistantSettings::register(cx);
     assistant_panel::init(cx);
+
+    let prompt_builder = prompts::PromptBuilder::new(Some(PromptLoadingParams {
+        fs: fs.clone(),
+        repo_path: stdout_is_a_pty
+            .then(|| std::env::current_dir().log_err())
+            .flatten(),
+        cx,
+    }))
+    .log_err()
+    .map(Arc::new)
+    .unwrap_or_else(|| Arc::new(prompts::PromptBuilder::new(None).unwrap()));
+    inline_assistant::init(
+        fs.clone(),
+        prompt_builder.clone(),
+        client.telemetry().clone(),
+        cx,
+    );
+
     feature_gate_assistant2_actions(cx);
 }
 

crates/assistant2/src/assistant_settings.rs

@@ -0,0 +1,485 @@
+use std::sync::Arc;
+
+use ::open_ai::Model as OpenAiModel;
+use anthropic::Model as AnthropicModel;
+use gpui::Pixels;
+use language_model::{CloudModel, LanguageModel};
+use ollama::Model as OllamaModel;
+use schemars::{schema::Schema, JsonSchema};
+use serde::{Deserialize, Serialize};
+use settings::{Settings, SettingsSources};
+
+#[derive(Copy, Clone, Default, Debug, Serialize, Deserialize, JsonSchema)]
+#[serde(rename_all = "snake_case")]
+pub enum AssistantDockPosition {
+    Left,
+    #[default]
+    Right,
+    Bottom,
+}
+
+#[derive(Clone, Debug, Serialize, Deserialize, JsonSchema, PartialEq)]
+#[serde(tag = "name", rename_all = "snake_case")]
+pub enum AssistantProviderContentV1 {
+    #[serde(rename = "zed.dev")]
+    ZedDotDev { default_model: Option<CloudModel> },
+    #[serde(rename = "openai")]
+    OpenAi {
+        default_model: Option<OpenAiModel>,
+        api_url: Option<String>,
+        available_models: Option<Vec<OpenAiModel>>,
+    },
+    #[serde(rename = "anthropic")]
+    Anthropic {
+        default_model: Option<AnthropicModel>,
+        api_url: Option<String>,
+    },
+    #[serde(rename = "ollama")]
+    Ollama {
+        default_model: Option<OllamaModel>,
+        api_url: Option<String>,
+    },
+}
+
+#[derive(Debug, Default)]
+pub struct AssistantSettings {
+    pub enabled: bool,
+    pub button: bool,
+    pub dock: AssistantDockPosition,
+    pub default_width: Pixels,
+    pub default_height: Pixels,
+    pub default_model: LanguageModelSelection,
+    pub inline_alternatives: Vec<LanguageModelSelection>,
+    pub using_outdated_settings_version: bool,
+    pub enable_experimental_live_diffs: bool,
+}
+
+/// Assistant panel settings
+#[derive(Clone, Serialize, Deserialize, Debug)]
+#[serde(untagged)]
+pub enum AssistantSettingsContent {
+    Versioned(VersionedAssistantSettingsContent),
+    Legacy(LegacyAssistantSettingsContent),
+}
+
+impl JsonSchema for AssistantSettingsContent {
+    fn schema_name() -> String {
+        VersionedAssistantSettingsContent::schema_name()
+    }
+
+    fn json_schema(gen: &mut schemars::gen::SchemaGenerator) -> Schema {
+        VersionedAssistantSettingsContent::json_schema(gen)
+    }
+
+    fn is_referenceable() -> bool {
+        VersionedAssistantSettingsContent::is_referenceable()
+    }
+}
+
+impl Default for AssistantSettingsContent {
+    fn default() -> Self {
+        Self::Versioned(VersionedAssistantSettingsContent::default())
+    }
+}
+
+impl AssistantSettingsContent {
+    pub fn is_version_outdated(&self) -> bool {
+        match self {
+            AssistantSettingsContent::Versioned(settings) => match settings {
+                VersionedAssistantSettingsContent::V1(_) => true,
+                VersionedAssistantSettingsContent::V2(_) => false,
+            },
+            AssistantSettingsContent::Legacy(_) => true,
+        }
+    }
+
+    fn upgrade(&self) -> AssistantSettingsContentV2 {
+        match self {
+            AssistantSettingsContent::Versioned(settings) => match settings {
+                VersionedAssistantSettingsContent::V1(settings) => AssistantSettingsContentV2 {
+                    enabled: settings.enabled,
+                    button: settings.button,
+                    dock: settings.dock,
+                    default_width: settings.default_width,
+                    default_height: settings.default_width,
+                    default_model: settings
+                        .provider
+                        .clone()
+                        .and_then(|provider| match provider {
+                            AssistantProviderContentV1::ZedDotDev { default_model } => {
+                                default_model.map(|model| LanguageModelSelection {
+                                    provider: "zed.dev".to_string(),
+                                    model: model.id().to_string(),
+                                })
+                            }
+                            AssistantProviderContentV1::OpenAi { default_model, .. } => {
+                                default_model.map(|model| LanguageModelSelection {
+                                    provider: "openai".to_string(),
+                                    model: model.id().to_string(),
+                                })
+                            }
+                            AssistantProviderContentV1::Anthropic { default_model, .. } => {
+                                default_model.map(|model| LanguageModelSelection {
+                                    provider: "anthropic".to_string(),
+                                    model: model.id().to_string(),
+                                })
+                            }
+                            AssistantProviderContentV1::Ollama { default_model, .. } => {
+                                default_model.map(|model| LanguageModelSelection {
+                                    provider: "ollama".to_string(),
+                                    model: model.id().to_string(),
+                                })
+                            }
+                        }),
+                    inline_alternatives: None,
+                    enable_experimental_live_diffs: None,
+                },
+                VersionedAssistantSettingsContent::V2(settings) => settings.clone(),
+            },
+            AssistantSettingsContent::Legacy(settings) => AssistantSettingsContentV2 {
+                enabled: None,
+                button: settings.button,
+                dock: settings.dock,
+                default_width: settings.default_width,
+                default_height: settings.default_height,
+                default_model: Some(LanguageModelSelection {
+                    provider: "openai".to_string(),
+                    model: settings
+                        .default_open_ai_model
+                        .clone()
+                        .unwrap_or_default()
+                        .id()
+                        .to_string(),
+                }),
+                inline_alternatives: None,
+                enable_experimental_live_diffs: None,
+            },
+        }
+    }
+
+    pub fn set_model(&mut self, language_model: Arc<dyn LanguageModel>) {
+        let model = language_model.id().0.to_string();
+        let provider = language_model.provider_id().0.to_string();
+
+        match self {
+            AssistantSettingsContent::Versioned(settings) => match settings {
+                VersionedAssistantSettingsContent::V1(settings) => match provider.as_ref() {
+                    "zed.dev" => {
+                        log::warn!("attempted to set zed.dev model on outdated settings");
+                    }
+                    "anthropic" => {
+                        let api_url = match &settings.provider {
+                            Some(AssistantProviderContentV1::Anthropic { api_url, .. }) => {
+                                api_url.clone()
+                            }
+                            _ => None,
+                        };
+                        settings.provider = Some(AssistantProviderContentV1::Anthropic {
+                            default_model: AnthropicModel::from_id(&model).ok(),
+                            api_url,
+                        });
+                    }
+                    "ollama" => {
+                        let api_url = match &settings.provider {
+                            Some(AssistantProviderContentV1::Ollama { api_url, .. }) => {
+                                api_url.clone()
+                            }
+                            _ => None,
+                        };
+                        settings.provider = Some(AssistantProviderContentV1::Ollama {
+                            default_model: Some(ollama::Model::new(&model, None, None)),
+                            api_url,
+                        });
+                    }
+                    "openai" => {
+                        let (api_url, available_models) = match &settings.provider {
+                            Some(AssistantProviderContentV1::OpenAi {
+                                api_url,
+                                available_models,
+                                ..
+                            }) => (api_url.clone(), available_models.clone()),
+                            _ => (None, None),
+                        };
+                        settings.provider = Some(AssistantProviderContentV1::OpenAi {
+                            default_model: OpenAiModel::from_id(&model).ok(),
+                            api_url,
+                            available_models,
+                        });
+                    }
+                    _ => {}
+                },
+                VersionedAssistantSettingsContent::V2(settings) => {
+                    settings.default_model = Some(LanguageModelSelection { provider, model });
+                }
+            },
+            AssistantSettingsContent::Legacy(settings) => {
+                if let Ok(model) = OpenAiModel::from_id(&language_model.id().0) {
+                    settings.default_open_ai_model = Some(model);
+                }
+            }
+        }
+    }
+}
+
+#[derive(Clone, Serialize, Deserialize, JsonSchema, Debug)]
+#[serde(tag = "version")]
+pub enum VersionedAssistantSettingsContent {
+    #[serde(rename = "1")]
+    V1(AssistantSettingsContentV1),
+    #[serde(rename = "2")]
+    V2(AssistantSettingsContentV2),
+}
+
+impl Default for VersionedAssistantSettingsContent {
+    fn default() -> Self {
+        Self::V2(AssistantSettingsContentV2 {
+            enabled: None,
+            button: None,
+            dock: None,
+            default_width: None,
+            default_height: None,
+            default_model: None,
+            inline_alternatives: None,
+            enable_experimental_live_diffs: None,
+        })
+    }
+}
+
+#[derive(Clone, Serialize, Deserialize, JsonSchema, Debug)]
+pub struct AssistantSettingsContentV2 {
+    /// Whether the Assistant is enabled.
+    ///
+    /// Default: true
+    enabled: Option<bool>,
+    /// Whether to show the assistant panel button in the status bar.
+    ///
+    /// Default: true
+    button: Option<bool>,
+    /// Where to dock the assistant.
+    ///
+    /// Default: right
+    dock: Option<AssistantDockPosition>,
+    /// Default width in pixels when the assistant is docked to the left or right.
+    ///
+    /// Default: 640
+    default_width: Option<f32>,
+    /// Default height in pixels when the assistant is docked to the bottom.
+    ///
+    /// Default: 320
+    default_height: Option<f32>,
+    /// The default model to use when creating new chats.
+    default_model: Option<LanguageModelSelection>,
+    /// Additional models with which to generate alternatives when performing inline assists.
+    inline_alternatives: Option<Vec<LanguageModelSelection>>,
+    /// Enable experimental live diffs in the assistant panel.
+    ///
+    /// Default: false
+    enable_experimental_live_diffs: Option<bool>,
+}
+
+#[derive(Clone, Debug, Serialize, Deserialize, JsonSchema, PartialEq)]
+pub struct LanguageModelSelection {
+    #[schemars(schema_with = "providers_schema")]
+    pub provider: String,
+    pub model: String,
+}
+
+fn providers_schema(_: &mut schemars::gen::SchemaGenerator) -> schemars::schema::Schema {
+    schemars::schema::SchemaObject {
+        enum_values: Some(vec![
+            "anthropic".into(),
+            "google".into(),
+            "ollama".into(),
+            "openai".into(),
+            "zed.dev".into(),
+            "copilot_chat".into(),
+        ]),
+        ..Default::default()
+    }
+    .into()
+}
+
+impl Default for LanguageModelSelection {
+    fn default() -> Self {
+        Self {
+            provider: "openai".to_string(),
+            model: "gpt-4".to_string(),
+        }
+    }
+}
+
+#[derive(Clone, Serialize, Deserialize, JsonSchema, Debug)]
+pub struct AssistantSettingsContentV1 {
+    /// Whether the Assistant is enabled.
+    ///
+    /// Default: true
+    enabled: Option<bool>,
+    /// Whether to show the assistant panel button in the status bar.
+    ///
+    /// Default: true
+    button: Option<bool>,
+    /// Where to dock the assistant.
+    ///
+    /// Default: right
+    dock: Option<AssistantDockPosition>,
+    /// Default width in pixels when the assistant is docked to the left or right.
+    ///
+    /// Default: 640
+    default_width: Option<f32>,
+    /// Default height in pixels when the assistant is docked to the bottom.
+    ///
+    /// Default: 320
+    default_height: Option<f32>,
+    /// The provider of the assistant service.
+    ///
+    /// This can be "openai", "anthropic", "ollama", "zed.dev"
+    /// each with their respective default models and configurations.
+    provider: Option<AssistantProviderContentV1>,
+}
+
+#[derive(Clone, Serialize, Deserialize, JsonSchema, Debug)]
+pub struct LegacyAssistantSettingsContent {
+    /// Whether to show the assistant panel button in the status bar.
+    ///
+    /// Default: true
+    pub button: Option<bool>,
+    /// Where to dock the assistant.
+    ///
+    /// Default: right
+    pub dock: Option<AssistantDockPosition>,
+    /// Default width in pixels when the assistant is docked to the left or right.
+    ///
+    /// Default: 640
+    pub default_width: Option<f32>,
+    /// Default height in pixels when the assistant is docked to the bottom.
+    ///
+    /// Default: 320
+    pub default_height: Option<f32>,
+    /// The default OpenAI model to use when creating new chats.
+    ///
+    /// Default: gpt-4-1106-preview
+    pub default_open_ai_model: Option<OpenAiModel>,
+    /// OpenAI API base URL to use when creating new chats.
+    ///
+    /// Default: https://api.openai.com/v1
+    pub openai_api_url: Option<String>,
+}
+
+impl Settings for AssistantSettings {
+    const KEY: Option<&'static str> = Some("assistant");
+
+    const PRESERVED_KEYS: Option<&'static [&'static str]> = Some(&["version"]);
+
+    type FileContent = AssistantSettingsContent;
+
+    fn load(
+        sources: SettingsSources<Self::FileContent>,
+        _: &mut gpui::AppContext,
+    ) -> anyhow::Result<Self> {
+        let mut settings = AssistantSettings::default();
+
+        for value in sources.defaults_and_customizations() {
+            if value.is_version_outdated() {
+                settings.using_outdated_settings_version = true;
+            }
+
+            let value = value.upgrade();
+            merge(&mut settings.enabled, value.enabled);
+            merge(&mut settings.button, value.button);
+            merge(&mut settings.dock, value.dock);
+            merge(
+                &mut settings.default_width,
+                value.default_width.map(Into::into),
+            );
+            merge(
+                &mut settings.default_height,
+                value.default_height.map(Into::into),
+            );
+            merge(&mut settings.default_model, value.default_model);
+            merge(&mut settings.inline_alternatives, value.inline_alternatives);
+            merge(
+                &mut settings.enable_experimental_live_diffs,
+                value.enable_experimental_live_diffs,
+            );
+        }
+
+        Ok(settings)
+    }
+}
+
+fn merge<T>(target: &mut T, value: Option<T>) {
+    if let Some(value) = value {
+        *target = value;
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use fs::Fs;
+    use gpui::{ReadGlobal, TestAppContext};
+
+    use super::*;
+
+    #[gpui::test]
+    async fn test_deserialize_assistant_settings_with_version(cx: &mut TestAppContext) {
+        let fs = fs::FakeFs::new(cx.executor().clone());
+        fs.create_dir(paths::settings_file().parent().unwrap())
+            .await
+            .unwrap();
+
+        cx.update(|cx| {
+            let test_settings = settings::SettingsStore::test(cx);
+            cx.set_global(test_settings);
+            AssistantSettings::register(cx);
+        });
+
+        cx.update(|cx| {
+            assert!(!AssistantSettings::get_global(cx).using_outdated_settings_version);
+            assert_eq!(
+                AssistantSettings::get_global(cx).default_model,
+                LanguageModelSelection {
+                    provider: "zed.dev".into(),
+                    model: "claude-3-5-sonnet".into(),
+                }
+            );
+        });
+
+        cx.update(|cx| {
+            settings::SettingsStore::global(cx).update_settings_file::<AssistantSettings>(
+                fs.clone(),
+                |settings, _| {
+                    *settings = AssistantSettingsContent::Versioned(
+                        VersionedAssistantSettingsContent::V2(AssistantSettingsContentV2 {
+                            default_model: Some(LanguageModelSelection {
+                                provider: "test-provider".into(),
+                                model: "gpt-99".into(),
+                            }),
+                            inline_alternatives: None,
+                            enabled: None,
+                            button: None,
+                            dock: None,
+                            default_width: None,
+                            default_height: None,
+                            enable_experimental_live_diffs: None,
+                        }),
+                    )
+                },
+            );
+        });
+
+        cx.run_until_parked();
+
+        let raw_settings_value = fs.load(paths::settings_file()).await.unwrap();
+        assert!(raw_settings_value.contains(r#""version": "2""#));
+
+        #[derive(Debug, Deserialize)]
+        struct AssistantSettingsTest {
+            assistant: AssistantSettingsContent,
+        }
+
+        let assistant_settings: AssistantSettingsTest =
+            serde_json_lenient::from_str(&raw_settings_value).unwrap();
+
+        assert!(!assistant_settings.assistant.is_version_outdated());
+    }
+}

crates/assistant2/src/prompts.rs

@@ -0,0 +1,291 @@
+use anyhow::Result;
+use assets::Assets;
+use fs::Fs;
+use futures::StreamExt;
+use gpui::AssetSource;
+use handlebars::{Handlebars, RenderError};
+use language::{BufferSnapshot, LanguageName, Point};
+use parking_lot::Mutex;
+use serde::Serialize;
+use std::{ops::Range, path::PathBuf, sync::Arc, time::Duration};
+use text::LineEnding;
+use util::ResultExt;
+
+#[derive(Serialize)]
+pub struct ContentPromptDiagnosticContext {
+    pub line_number: usize,
+    pub error_message: String,
+    pub code_content: String,
+}
+
+#[derive(Serialize)]
+pub struct ContentPromptContext {
+    pub content_type: String,
+    pub language_name: Option<String>,
+    pub is_insert: bool,
+    pub is_truncated: bool,
+    pub document_content: String,
+    pub user_prompt: String,
+    pub rewrite_section: Option<String>,
+    pub diagnostic_errors: Vec<ContentPromptDiagnosticContext>,
+}
+
+#[derive(Serialize)]
+pub struct TerminalAssistantPromptContext {
+    pub os: String,
+    pub arch: String,
+    pub shell: Option<String>,
+    pub working_directory: Option<String>,
+    pub latest_output: Vec<String>,
+    pub user_prompt: String,
+}
+
+#[derive(Serialize)]
+pub struct ProjectSlashCommandPromptContext {
+    pub context_buffer: String,
+}
+
+pub struct PromptLoadingParams<'a> {
+    pub fs: Arc<dyn Fs>,
+    pub repo_path: Option<PathBuf>,
+    pub cx: &'a gpui::AppContext,
+}
+
+pub struct PromptBuilder {
+    handlebars: Arc<Mutex<Handlebars<'static>>>,
+}
+
+impl PromptBuilder {
+    pub fn new(loading_params: Option<PromptLoadingParams>) -> Result<Self> {
+        let mut handlebars = Handlebars::new();
+        Self::register_built_in_templates(&mut handlebars)?;
+
+        let handlebars = Arc::new(Mutex::new(handlebars));
+
+        if let Some(params) = loading_params {
+            Self::watch_fs_for_template_overrides(params, handlebars.clone());
+        }
+
+        Ok(Self { handlebars })
+    }
+
+    /// Watches the filesystem for changes to prompt template overrides.
+    ///
+    /// This function sets up a file watcher on the prompt templates directory. It performs
+    /// an initial scan of the directory and registers any existing template overrides.
+    /// Then it continuously monitors for changes, reloading templates as they are
+    /// modified or added.
+    ///
+    /// If the templates directory doesn't exist initially, it waits for it to be created.
+    /// If the directory is removed, it restores the built-in templates and waits for the
+    /// directory to be recreated.
+    ///
+    /// # Arguments
+    ///
+    /// * `params` - A `PromptLoadingParams` struct containing the filesystem, repository path,
+    ///   and application context.
+    /// * `handlebars` - An `Arc<Mutex<Handlebars>>` for registering and updating templates.
+    fn watch_fs_for_template_overrides(
+        params: PromptLoadingParams,
+        handlebars: Arc<Mutex<Handlebars<'static>>>,
+    ) {
+        let templates_dir = paths::prompt_overrides_dir(params.repo_path.as_deref());
+        params.cx.background_executor()
+            .spawn(async move {
+                let Some(parent_dir) = templates_dir.parent() else {
+                    return;
+                };
+
+                let mut found_dir_once = false;
+                loop {
+                    // Check if the templates directory exists and handle its status
+                    // If it exists, log its presence and check if it's a symlink
+                    // If it doesn't exist:
+                    //   - Log that we're using built-in prompts
+                    //   - Check if it's a broken symlink and log if so
+                    //   - Set up a watcher to detect when it's created
+                    // After the first check, set the `found_dir_once` flag
+                    // This allows us to avoid logging when looping back around after deleting the prompt overrides directory.
+                    let dir_status = params.fs.is_dir(&templates_dir).await;
+                    let symlink_status = params.fs.read_link(&templates_dir).await.ok();
+                    if dir_status {
+                        let mut log_message = format!("Prompt template overrides directory found at {}", templates_dir.display());
+                        if let Some(target) = symlink_status {
+                            log_message.push_str(" -> ");
+                            log_message.push_str(&target.display().to_string());
+                        }
+                        log::info!("{}.", log_message);
+                    } else {
+                        if !found_dir_once {
+                            log::info!("No prompt template overrides directory found at {}. Using built-in prompts.", templates_dir.display());
+                            if let Some(target) = symlink_status {
+                                log::info!("Symlink found pointing to {}, but target is invalid.", target.display());
+                            }
+                        }
+
+                        if params.fs.is_dir(parent_dir).await {
+                            let (mut changes, _watcher) = params.fs.watch(parent_dir, Duration::from_secs(1)).await;
+                            while let Some(changed_paths) = changes.next().await {
+                                if changed_paths.iter().any(|p| &p.path == &templates_dir) {
+                                    let mut log_message = format!("Prompt template overrides directory detected at {}", templates_dir.display());
+                                    if let Ok(target) = params.fs.read_link(&templates_dir).await {
+                                        log_message.push_str(" -> ");
+                                        log_message.push_str(&target.display().to_string());
+                                    }
+                                    log::info!("{}.", log_message);
+                                    break;
+                                }
+                            }
+                        } else {
+                            return;
+                        }
+                    }
+
+                    found_dir_once = true;
+
+                    // Initial scan of the prompt overrides directory
+                    if let Ok(mut entries) = params.fs.read_dir(&templates_dir).await {
+                        while let Some(Ok(file_path)) = entries.next().await {
+                            if file_path.to_string_lossy().ends_with(".hbs") {
+                                if let Ok(content) = params.fs.load(&file_path).await {
+                                    let file_name = file_path.file_stem().unwrap().to_string_lossy();
+                                    log::debug!("Registering prompt template override: {}", file_name);
+                                    handlebars.lock().register_template_string(&file_name, content).log_err();
+                                }
+                            }
+                        }
+                    }
+
+                    // Watch both the parent directory and the template overrides directory:
+                    // - Monitor the parent directory to detect if the template overrides directory is deleted.
+                    // - Monitor the template overrides directory to re-register templates when they change.
+                    // Combine both watch streams into a single stream.
+                    let (parent_changes, parent_watcher) = params.fs.watch(parent_dir, Duration::from_secs(1)).await;
+                    let (changes, watcher) = params.fs.watch(&templates_dir, Duration::from_secs(1)).await;
+                    let mut combined_changes = futures::stream::select(changes, parent_changes);
+
+                    while let Some(changed_paths) = combined_changes.next().await {
+                        if changed_paths.iter().any(|p| &p.path == &templates_dir) {
+                            if !params.fs.is_dir(&templates_dir).await {
+                                log::info!("Prompt template overrides directory removed. Restoring built-in prompt templates.");
+                                Self::register_built_in_templates(&mut handlebars.lock()).log_err();
+                                break;
+                            }
+                        }
+                        for event in changed_paths {
+                            if event.path.starts_with(&templates_dir) && event.path.extension().map_or(false, |ext| ext == "hbs") {
+                                log::info!("Reloading prompt template override: {}", event.path.display());
+                                if let Some(content) = params.fs.load(&event.path).await.log_err() {
+                                    let file_name = event.path.file_stem().unwrap().to_string_lossy();
+                                    handlebars.lock().register_template_string(&file_name, content).log_err();
+                                }
+                            }
+                        }
+                    }
+
+                    drop(watcher);
+                    drop(parent_watcher);
+                }
+            })
+            .detach();
+    }
+
+    fn register_built_in_templates(handlebars: &mut Handlebars) -> Result<()> {
+        for path in Assets.list("prompts")? {
+            if let Some(id) = path.split('/').last().and_then(|s| s.strip_suffix(".hbs")) {
+                if let Some(prompt) = Assets.load(path.as_ref()).log_err().flatten() {
+                    log::debug!("Registering built-in prompt template: {}", id);
+                    let prompt = String::from_utf8_lossy(prompt.as_ref());
+                    handlebars.register_template_string(id, LineEnding::normalize_cow(prompt))?
+                }
+            }
+        }
+
+        Ok(())
+    }
+
+    pub fn generate_inline_transformation_prompt(
+        &self,
+        user_prompt: String,
+        language_name: Option<&LanguageName>,
+        buffer: BufferSnapshot,
+        range: Range<usize>,
+    ) -> Result<String, RenderError> {
+        let content_type = match language_name.as_ref().map(|l| l.0.as_ref()) {
+            None | Some("Markdown" | "Plain Text") => "text",
+            Some(_) => "code",
+        };
+
+        const MAX_CTX: usize = 50000;
+        let is_insert = range.is_empty();
+        let mut is_truncated = false;
+
+        let before_range = 0..range.start;
+        let truncated_before = if before_range.len() > MAX_CTX {
+            is_truncated = true;
+            let start = buffer.clip_offset(range.start - MAX_CTX, text::Bias::Right);
+            start..range.start
+        } else {
+            before_range
+        };
+
+        let after_range = range.end..buffer.len();
+        let truncated_after = if after_range.len() > MAX_CTX {
+            is_truncated = true;
+            let end = buffer.clip_offset(range.end + MAX_CTX, text::Bias::Left);
+            range.end..end
+        } else {
+            after_range
+        };
+
+        let mut document_content = String::new();
+        for chunk in buffer.text_for_range(truncated_before) {
+            document_content.push_str(chunk);
+        }
+        if is_insert {
+            document_content.push_str("<insert_here></insert_here>");
+        } else {
+            document_content.push_str("<rewrite_this>\n");
+            for chunk in buffer.text_for_range(range.clone()) {
+                document_content.push_str(chunk);
+            }
+            document_content.push_str("\n</rewrite_this>");
+        }
+        for chunk in buffer.text_for_range(truncated_after) {
+            document_content.push_str(chunk);
+        }
+
+        let rewrite_section = if !is_insert {
+            let mut section = String::new();
+            for chunk in buffer.text_for_range(range.clone()) {
+                section.push_str(chunk);
+            }
+            Some(section)
+        } else {
+            None
+        };
+        let diagnostics = buffer.diagnostics_in_range::<_, Point>(range, false);
+        let diagnostic_errors: Vec<ContentPromptDiagnosticContext> = diagnostics
+            .map(|entry| {
+                let start = entry.range.start;
+                ContentPromptDiagnosticContext {
+                    line_number: (start.row + 1) as usize,
+                    error_message: entry.diagnostic.message.clone(),
+                    code_content: buffer.text_for_range(entry.range.clone()).collect(),
+                }
+            })
+            .collect();
+
+        let context = ContentPromptContext {
+            content_type: content_type.to_string(),
+            language_name: language_name.map(|s| s.to_string()),
+            is_insert,
+            is_truncated,
+            document_content,
+            user_prompt,
+            rewrite_section,
+            diagnostic_errors,
+        };
+        self.handlebars.lock().render("content_prompt", &context)
+    }
+}

crates/zed/src/main.rs

@@ -406,7 +406,12 @@ fn main() {
             stdout_is_a_pty(),
             cx,
         );
-        assistant2::init(cx);
+        assistant2::init(
+            app_state.fs.clone(),
+            app_state.client.clone(),
+            stdout_is_a_pty(),
+            cx,
+        );
         assistant_tools::init(cx);
         repl::init(
             app_state.fs.clone(),