Include project rules in commit message generation (#44921)

Closes #38027

Release Notes:

- AI-generated commit messages now respect rules files (e.g.
`AGENTS.md`) if present

---------

Co-authored-by: Claude Haiku 4.5 <noreply@anthropic.com>

Cargo.lock

@@ -7077,6 +7077,7 @@ dependencies = [
  "picker",
  "pretty_assertions",
  "project",
+ "prompt_store",
  "rand 0.9.2",
  "recent_projects",
  "remote",

crates/agent/src/agent.rs

@@ -33,7 +33,8 @@ use gpui::{
 use language_model::{LanguageModel, LanguageModelProvider, LanguageModelRegistry};
 use project::{Project, ProjectItem, ProjectPath, Worktree};
 use prompt_store::{
-    ProjectContext, PromptStore, RulesFileContext, UserRulesContext, WorktreeContext,
+    ProjectContext, PromptStore, RULES_FILE_NAMES, RulesFileContext, UserRulesContext,
+    WorktreeContext,
 };
 use serde::{Deserialize, Serialize};
 use settings::{LanguageModelSelection, update_settings_file};
@@ -51,18 +52,6 @@ pub struct ProjectSnapshot {
     pub timestamp: DateTime<Utc>,
 }
 
-const RULES_FILE_NAMES: [&str; 9] = [
-    ".rules",
-    ".cursorrules",
-    ".windsurfrules",
-    ".clinerules",
-    ".github/copilot-instructions.md",
-    "CLAUDE.md",
-    "AGENT.md",
-    "AGENTS.md",
-    "GEMINI.md",
-];
-
 pub struct RulesLoadingError {
     pub message: SharedString,
 }

crates/git_ui/Cargo.toml

@@ -43,6 +43,7 @@ notifications.workspace = true
 panel.workspace = true
 picker.workspace = true
 project.workspace = true
+prompt_store.workspace = true
 recent_projects.workspace = true
 remote.workspace = true
 schemars.workspace = true

crates/git_ui/src/git_panel.rs

@@ -57,6 +57,7 @@ use project::{
     git_store::{GitStoreEvent, Repository, RepositoryEvent, RepositoryId, pending_op},
     project_settings::{GitPathStyle, ProjectSettings},
 };
+use prompt_store::RULES_FILE_NAMES;
 use serde::{Deserialize, Serialize};
 use settings::{Settings, SettingsStore, StatusStyle};
 use std::future::Future;
@@ -71,7 +72,7 @@ use ui::{
     prelude::*,
 };
 use util::paths::PathStyle;
-use util::{ResultExt, TryFutureExt, maybe};
+use util::{ResultExt, TryFutureExt, maybe, rel_path::RelPath};
 use workspace::SERIALIZATION_THROTTLE_TIME;
 use workspace::{
     Workspace,
@@ -2325,6 +2326,56 @@ impl GitPanel {
         compressed
     }
 
+    async fn load_project_rules(
+        project: &Entity<Project>,
+        repo_work_dir: &Arc<Path>,
+        cx: &mut AsyncApp,
+    ) -> Option<String> {
+        let rules_path = cx
+            .update(|cx| {
+                for worktree in project.read(cx).worktrees(cx) {
+                    let worktree_abs_path = worktree.read(cx).abs_path();
+                    if !worktree_abs_path.starts_with(&repo_work_dir) {
+                        continue;
+                    }
+
+                    let worktree_snapshot = worktree.read(cx).snapshot();
+                    for rules_name in RULES_FILE_NAMES {
+                        if let Ok(rel_path) = RelPath::unix(rules_name) {
+                            if let Some(entry) = worktree_snapshot.entry_for_path(rel_path) {
+                                if entry.is_file() {
+                                    return Some(ProjectPath {
+                                        worktree_id: worktree.read(cx).id(),
+                                        path: entry.path.clone(),
+                                    });
+                                }
+                            }
+                        }
+                    }
+                }
+                None
+            })
+            .ok()??;
+
+        let buffer = project
+            .update(cx, |project, cx| project.open_buffer(rules_path, cx))
+            .ok()?
+            .await
+            .ok()?;
+
+        let content = buffer
+            .read_with(cx, |buffer, _| buffer.text())
+            .ok()?
+            .trim()
+            .to_string();
+
+        if content.is_empty() {
+            None
+        } else {
+            Some(content)
+        }
+    }
+
     /// Generates a commit message using an LLM.
     pub fn generate_commit_message(&mut self, cx: &mut Context<Self>) {
         if !self.can_commit() || !AgentSettings::get_global(cx).enabled(cx) {
@@ -2352,8 +2403,10 @@ impl GitPanel {
         });
 
         let temperature = AgentSettings::temperature_for_model(&model, cx);
+        let project = self.project.clone();
+        let repo_work_dir = repo.read(cx).work_directory_abs_path.clone();
 
-        self.generate_commit_message_task = Some(cx.spawn(async move |this, cx| {
+        self.generate_commit_message_task = Some(cx.spawn(async move |this, mut cx| {
              async move {
                 let _defer = cx.on_drop(&this, |this, _cx| {
                     this.generate_commit_message_task.take();
@@ -2386,19 +2439,33 @@ impl GitPanel {
                 const MAX_DIFF_BYTES: usize = 20_000;
                 diff_text = Self::compress_commit_diff(&diff_text, MAX_DIFF_BYTES);
 
+                let rules_content = Self::load_project_rules(&project, &repo_work_dir, &mut cx).await;
+
                 let subject = this.update(cx, |this, cx| {
                     this.commit_editor.read(cx).text(cx).lines().next().map(ToOwned::to_owned).unwrap_or_default()
                 })?;
 
                 let text_empty = subject.trim().is_empty();
 
-                let content = if text_empty {
-                    format!("{PROMPT}\nHere are the changes in this commit:\n{diff_text}")
-                } else {
-                    format!("{PROMPT}\nHere is the user's subject line:\n{subject}\nHere are the changes in this commit:\n{diff_text}\n")
+                const PROMPT: &str = include_str!("commit_message_prompt.txt");
+
+                let rules_section = match &rules_content {
+                    Some(rules) => format!(
+                        "\n\nThe user has provided the following project rules that you should follow when writing the commit message:\n\
+                        <project_rules>\n{rules}\n</project_rules>\n"
+                    ),
+                    None => String::new(),
                 };
 
-                const PROMPT: &str = include_str!("commit_message_prompt.txt");
+                let subject_section = if text_empty {
+                    String::new()
+                } else {
+                    format!("\nHere is the user's subject line:\n{subject}")
+                };
+
+                let content = format!(
+                    "{PROMPT}{rules_section}{subject_section}\nHere are the changes in this commit:\n{diff_text}"
+                );
 
                 let request = LanguageModelRequest {
                     thread_id: None,

crates/prompt_store/src/prompts.rs

@@ -20,6 +20,18 @@ use util::{
 
 use crate::UserPromptId;
 
+pub const RULES_FILE_NAMES: &[&str] = &[
+    ".rules",
+    ".cursorrules",
+    ".windsurfrules",
+    ".clinerules",
+    ".github/copilot-instructions.md",
+    "CLAUDE.md",
+    "AGENT.md",
+    "AGENTS.md",
+    "GEMINI.md",
+];
+
 #[derive(Default, Debug, Clone, Serialize)]
 pub struct ProjectContext {
     pub worktrees: Vec<WorktreeContext>,