feat: improve commit message generation and cleaning

Author: gtkacz

.gitignore

@@ -32,3 +32,4 @@ target
 .mcp.json
 .python-version
 lcov.info
+.env

src/config.rs

@@ -18,8 +18,7 @@ const DEFAULT_SYSTEM_PROMPT: &str = "You are to act as an author of a commit mes
 Your mission is to create clean and comprehensive commit messages as per
 the Conventional Commit specification and explain WHAT were the changes and mainly WHY the changes were done.
 I'll send you an output of 'git diff --staged' command, and you are to convert
-it into a commit message. Use the present tense.
-Lines must not be longer than 80 characters. Use english for the commit message.";
+it into a commit message. Use the present tense. Use english for the commit message.";
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct AppConfig {

src/main.rs

@@ -257,9 +257,10 @@ fn generate_final_message(
         println!("\n{}", "LLM system prompt:".cyan().bold());
         println!("{system_prompt}\n");
     }
-    let (mut message, fallback_name) =
+    let (raw_message, fallback_name) =
         provider::call_llm_with_fallback(cfg, &system_prompt, diff)
             .context("LLM API call failed")?;
+    let mut message = prompt::clean_commit_message(&raw_message);
 
     if let Some(ref name) = fallback_name {
         println!(
@@ -273,7 +274,11 @@ fn generate_final_message(
 
     let final_msg = if cfg.review_commit {
         loop {
-            let candidate = cfg.commit_template.replace("$msg", message.trim());
+            let candidate = cfg
+                .commit_template
+                .replace("$msg", message.trim())
+                .trim()
+                .to_string();
 
             if time_to_ready.is_none() {
                 time_to_ready = Some(gen_start.elapsed());
@@ -284,10 +289,10 @@ fn generate_final_message(
             match review_message()? {
                 ReviewAction::Accept => break candidate,
                 ReviewAction::Regenerate => {
-                    let (new_msg, fb) =
+                    let (new_raw, fb) =
                         provider::call_llm_with_fallback(cfg, &system_prompt, diff)
                             .context("LLM API call failed")?;
-                    message = new_msg;
+                    message = prompt::clean_commit_message(&new_raw);
                     if let Some(ref name) = fb {
                         println!(
                             "  {} Used fallback preset: {}",
@@ -307,7 +312,11 @@ fn generate_final_message(
             }
         }
     } else {
-        let final_msg = cfg.commit_template.replace("$msg", message.trim());
+        let final_msg = cfg
+            .commit_template
+            .replace("$msg", message.trim())
+            .trim()
+            .to_string();
         time_to_ready = Some(gen_start.elapsed());
         println!("\n{} {}", "Commit message:".green().bold(), final_msg);
         final_msg

src/prompt.rs

@@ -70,3 +70,73 @@ pub fn build_system_prompt(cfg: &AppConfig) -> String {
 
     parts.join("\n\n")
 }
+
+/// Strip common LLM artifacts from the raw response so only the commit message remains.
+///
+/// Handles:
+/// - Markdown code fences (``` or ```commit / ```text / etc.)
+/// - Leading label lines ("Here is your commit message:", "Commit message:", etc.)
+/// - Surrounding quotation marks
+pub fn clean_commit_message(raw: &str) -> String {
+    let s = raw.trim();
+
+    // Strip markdown code fences
+    let s = strip_code_fence(s);
+
+    // Strip a leading label line (everything before the first blank line or
+    // the first line that looks like a conventional commit / gitmoji prefix).
+    let s = strip_label_prefix(s);
+
+    // Strip surrounding straight or curly quotes
+    let s = strip_surrounding_quotes(s);
+
+    s.trim().to_string()
+}
+
+fn strip_code_fence(s: &str) -> &str {
+    // Match opening fence with optional language tag (e.g., ```commit, ```text)
+    if let Some(inner) = s.strip_prefix("```") {
+        // Skip the language tag on the first line
+        let after_tag = inner.trim_start_matches(|c: char| c.is_alphanumeric() || c == '-');
+        // Must start with a newline after the tag
+        if let Some(body) = after_tag.strip_prefix('\n') {
+            if let Some(end) = body.rfind("```") {
+                return body[..end].trim();
+            }
+        }
+    }
+    s
+}
+
+fn strip_label_prefix(s: &str) -> &str {
+    // Common prefixes LLMs put before the actual message
+    let label_patterns: &[&str] = &[
+        "commit message:",
+        "here is the commit message:",
+        "here's the commit message:",
+        "here is your commit message:",
+        "here's your commit message:",
+        "generated commit message:",
+        "suggested commit message:",
+        "the commit message:",
+    ];
+
+    let lower = s.to_lowercase();
+    for pat in label_patterns {
+        if let Some(rest) = lower.strip_prefix(pat) {
+            // Trim blank lines / whitespace after the label
+            return s[pat.len()..][rest.len() - rest.trim_start().len()..].trim_start();
+        }
+    }
+    s
+}
+
+fn strip_surrounding_quotes(s: &str) -> &str {
+    let quote_pairs: &[(char, char)] = &[('"', '"'), ('\'', '\''), ('\u{201c}', '\u{201d}')];
+    for &(open, close) in quote_pairs {
+        if s.starts_with(open) && s.ends_with(close) && s.len() > 1 {
+            return &s[open.len_utf8()..s.len() - close.len_utf8()];
+        }
+    }
+    s
+}

tests/config_tests.rs

@@ -47,6 +47,8 @@ fn load_uses_defaults_when_no_layers_exist() {
     let _acr = EnvGuard::clear(&acr_env_keys());
 
     let _force = EnvGuard::set(&[
+        // Re-set after _acr cleared it so global_config_path() stays isolated
+        ("ACR_CONFIG_HOME", cfg_dir.path().to_string_lossy().as_ref()),
         ("ACR_PROVIDER", "groq"),
         ("ACR_MODEL", "llama-3.3-70b-versatile"),
         ("ACR_LOCALE", "en"),

tests/prompt_tests.rs

@@ -1,5 +1,5 @@
 use auto_commit_rs::config::AppConfig;
-use auto_commit_rs::prompt::build_system_prompt;
+use auto_commit_rs::prompt::{build_system_prompt, clean_commit_message};
 
 #[test]
 fn prompt_includes_core_sections_by_default() {
@@ -60,3 +60,42 @@ fn prompt_uses_custom_base_prompt() {
     let prompt = build_system_prompt(&cfg);
     assert!(prompt.starts_with("custom base prompt"));
 }
+
+#[test]
+fn clean_message_strips_markdown_code_fence() {
+    let raw = "```\nfeat: add login\n```";
+    assert_eq!(clean_commit_message(raw), "feat: add login");
+}
+
+#[test]
+fn clean_message_strips_code_fence_with_language_tag() {
+    let raw = "```commit\nfix(auth): correct redirect\n```";
+    assert_eq!(clean_commit_message(raw), "fix(auth): correct redirect");
+}
+
+#[test]
+fn clean_message_strips_label_prefix() {
+    let raw = "Here's your commit message:\nfeat: implement dark mode";
+    assert_eq!(clean_commit_message(raw), "feat: implement dark mode");
+}
+
+#[test]
+fn clean_message_strips_surrounding_quotes() {
+    let raw = "\"feat: add user authentication\"";
+    assert_eq!(clean_commit_message(raw), "feat: add user authentication");
+}
+
+#[test]
+fn clean_message_passes_through_clean_input() {
+    let raw = "feat(api): improve response time";
+    assert_eq!(clean_commit_message(raw), raw);
+}
+
+#[test]
+fn clean_message_handles_multiline_with_fence() {
+    let raw = "```\nfeat: add search\n\nAdds full-text search support.\n```";
+    assert_eq!(
+        clean_commit_message(raw),
+        "feat: add search\n\nAdds full-text search support."
+    );
+}