feat(prompts): implement customizable commit message prompts

- Added a new section in the UI for customizing commit message prompts.
- Integrated a system prompt for AI-generated commit messages, allowing users to define their own instructions.
- Updated the backend to merge custom prompts with default settings for commit message generation.
- Enhanced the commit message generation logic to utilize the effective system prompt based on user settings.

apps/ui/src/components/views/settings-view/prompts/prompt-customization-section.tsx

@@ -12,6 +12,7 @@ import {
   RotateCcw,
   Info,
   AlertTriangle,
+  GitCommitHorizontal,
 } from 'lucide-react';
 import { cn } from '@/lib/utils';
 import type { PromptCustomization, CustomPrompt } from '@automaker/types';
@@ -20,6 +21,7 @@ import {
   DEFAULT_AGENT_PROMPTS,
   DEFAULT_BACKLOG_PLAN_PROMPTS,
   DEFAULT_ENHANCEMENT_PROMPTS,
+  DEFAULT_COMMIT_MESSAGE_PROMPTS,
 } from '@automaker/prompts';
 
 interface PromptCustomizationSectionProps {
@@ -219,7 +221,7 @@ export function PromptCustomizationSection({
       {/* Tabs */}
       <div className="p-6">
         <Tabs value={activeTab} onValueChange={setActiveTab}>
-          <TabsList className="grid grid-cols-4 w-full">
+          <TabsList className="grid grid-cols-5 w-full">
             <TabsTrigger value="auto-mode" className="gap-2">
               <Bot className="w-4 h-4" />
               Auto Mode
@@ -236,6 +238,10 @@ export function PromptCustomizationSection({
               <Sparkles className="w-4 h-4" />
               Enhancement
             </TabsTrigger>
+            <TabsTrigger value="commit-message" className="gap-2">
+              <GitCommitHorizontal className="w-4 h-4" />
+              Commit
+            </TabsTrigger>
           </TabsList>
 
           {/* Auto Mode Tab */}
@@ -443,6 +449,34 @@ export function PromptCustomizationSection({
               />
             </div>
           </TabsContent>
+
+          {/* Commit Message Tab */}
+          <TabsContent value="commit-message" className="space-y-6 mt-6">
+            <div className="flex items-center justify-between mb-4">
+              <h3 className="text-sm font-medium text-foreground">Commit Message Prompts</h3>
+              <Button
+                variant="ghost"
+                size="sm"
+                onClick={() => resetToDefaults('commitMessage')}
+                className="gap-2"
+              >
+                <RotateCcw className="w-3 h-3" />
+                Reset Section
+              </Button>
+            </div>
+
+            <div className="space-y-4">
+              <PromptField
+                label="System Prompt"
+                description="Instructions for generating git commit messages from diffs. The AI will receive the git diff and generate a conventional commit message."
+                defaultValue={DEFAULT_COMMIT_MESSAGE_PROMPTS.systemPrompt}
+                customValue={promptCustomization?.commitMessage?.systemPrompt}
+                onCustomValueChange={(value) =>
+                  updatePrompt('commitMessage', 'systemPrompt', value)
+                }
+              />
+            </div>
+          </TabsContent>
         </Tabs>
       </div>
     </div>

libs/prompts/src/defaults.ts

@@ -15,6 +15,7 @@ import type {
   ResolvedAgentPrompts,
   ResolvedBacklogPlanPrompts,
   ResolvedEnhancementPrompts,
+  ResolvedCommitMessagePrompts,
 } from '@automaker/types';
 import { STATIC_PORT, SERVER_PORT } from '@automaker/types';
 
@@ -429,6 +430,40 @@ export const DEFAULT_ENHANCEMENT_PROMPTS: ResolvedEnhancementPrompts = {
   uxReviewerSystemPrompt: UX_REVIEWER_SYSTEM_PROMPT,
 };
 
+/**
+ * ========================================================================
+ * COMMIT MESSAGE PROMPTS
+ * ========================================================================
+ */
+
+export const DEFAULT_COMMIT_MESSAGE_SYSTEM_PROMPT = `You are a git commit message generator. Your task is to create a clear, concise commit message based on the git diff provided.
+
+Rules:
+- Output ONLY the commit message, nothing else
+- First line should be a short summary (50 chars or less) in imperative mood
+- Start with a conventional commit type if appropriate (feat:, fix:, refactor:, docs:, chore:, style:, test:, perf:, ci:, build:)
+- Keep it concise and descriptive
+- Focus on WHAT changed and WHY (if clear from the diff), not HOW
+- No quotes, backticks, or extra formatting
+- If there are multiple changes, provide a brief summary on the first line
+
+Examples:
+- feat: Add dark mode toggle to settings
+- fix: Resolve login validation edge case
+- refactor: Extract user authentication logic
+- docs: Update installation instructions
+- chore: Update dependencies to latest versions
+- style: Fix inconsistent indentation in components
+- test: Add unit tests for user service
+- perf: Optimize database query for user lookup`;
+
+/**
+ * Default Commit Message prompts (for AI commit message generation)
+ */
+export const DEFAULT_COMMIT_MESSAGE_PROMPTS: ResolvedCommitMessagePrompts = {
+  systemPrompt: DEFAULT_COMMIT_MESSAGE_SYSTEM_PROMPT,
+};
+
 /**
  * ========================================================================
  * COMBINED DEFAULTS
@@ -443,4 +478,5 @@ export const DEFAULT_PROMPTS = {
   agent: DEFAULT_AGENT_PROMPTS,
   backlogPlan: DEFAULT_BACKLOG_PLAN_PROMPTS,
   enhancement: DEFAULT_ENHANCEMENT_PROMPTS,
+  commitMessage: DEFAULT_COMMIT_MESSAGE_PROMPTS,
 } as const;

libs/prompts/src/index.ts

@@ -41,6 +41,8 @@ export {
   DEFAULT_BACKLOG_PLAN_USER_PROMPT_TEMPLATE,
   DEFAULT_BACKLOG_PLAN_PROMPTS,
   DEFAULT_ENHANCEMENT_PROMPTS,
+  DEFAULT_COMMIT_MESSAGE_SYSTEM_PROMPT,
+  DEFAULT_COMMIT_MESSAGE_PROMPTS,
   DEFAULT_PROMPTS,
 } from './defaults.js';
 
@@ -50,6 +52,7 @@ export {
   mergeAgentPrompts,
   mergeBacklogPlanPrompts,
   mergeEnhancementPrompts,
+  mergeCommitMessagePrompts,
   mergeAllPrompts,
 } from './merge.js';
 
@@ -59,4 +62,5 @@ export type {
   ResolvedAgentPrompts,
   ResolvedBacklogPlanPrompts,
   ResolvedEnhancementPrompts,
+  ResolvedCommitMessagePrompts,
 } from '@automaker/types';

libs/prompts/src/merge.ts

@@ -14,17 +14,20 @@ import type {
   AgentPrompts,
   BacklogPlanPrompts,
   EnhancementPrompts,
+  CommitMessagePrompts,
   CustomPrompt,
   ResolvedAutoModePrompts,
   ResolvedAgentPrompts,
   ResolvedBacklogPlanPrompts,
   ResolvedEnhancementPrompts,
+  ResolvedCommitMessagePrompts,
 } from '@automaker/types';
 import {
   DEFAULT_AUTO_MODE_PROMPTS,
   DEFAULT_AGENT_PROMPTS,
   DEFAULT_BACKLOG_PLAN_PROMPTS,
   DEFAULT_ENHANCEMENT_PROMPTS,
+  DEFAULT_COMMIT_MESSAGE_PROMPTS,
 } from './defaults.js';
 
 /**
@@ -120,6 +123,18 @@ export function mergeEnhancementPrompts(custom?: EnhancementPrompts): ResolvedEn
   };
 }
 
+/**
+ * Merge custom Commit Message prompts with defaults
+ * Custom prompts override defaults only when enabled=true
+ */
+export function mergeCommitMessagePrompts(
+  custom?: CommitMessagePrompts
+): ResolvedCommitMessagePrompts {
+  return {
+    systemPrompt: resolvePrompt(custom?.systemPrompt, DEFAULT_COMMIT_MESSAGE_PROMPTS.systemPrompt),
+  };
+}
+
 /**
  * Merge all custom prompts with defaults
  * Returns a complete PromptCustomization with all fields populated
@@ -130,5 +145,6 @@ export function mergeAllPrompts(custom?: PromptCustomization) {
     agent: mergeAgentPrompts(custom?.agent),
     backlogPlan: mergeBacklogPlanPrompts(custom?.backlogPlan),
     enhancement: mergeEnhancementPrompts(custom?.enhancement),
+    commitMessage: mergeCommitMessagePrompts(custom?.commitMessage),
   };
 }

libs/types/src/index.ts

@@ -98,11 +98,13 @@ export type {
   AgentPrompts,
   BacklogPlanPrompts,
   EnhancementPrompts,
+  CommitMessagePrompts,
   PromptCustomization,
   ResolvedAutoModePrompts,
   ResolvedAgentPrompts,
   ResolvedBacklogPlanPrompts,
   ResolvedEnhancementPrompts,
+  ResolvedCommitMessagePrompts,
 } from './prompts.js';
 export { DEFAULT_PROMPT_CUSTOMIZATION } from './prompts.js';
 

libs/types/src/prompts.ts

@@ -94,6 +94,16 @@ export interface EnhancementPrompts {
   uxReviewerSystemPrompt?: CustomPrompt;
 }
 
+/**
+ * CommitMessagePrompts - Customizable prompts for AI commit message generation
+ *
+ * Controls how the AI generates git commit messages from diffs.
+ */
+export interface CommitMessagePrompts {
+  /** System prompt for generating commit messages */
+  systemPrompt?: CustomPrompt;
+}
+
 /**
  * PromptCustomization - Complete set of customizable prompts
  *
@@ -112,6 +122,9 @@ export interface PromptCustomization {
 
   /** Enhancement prompts (feature description improvement) */
   enhancement?: EnhancementPrompts;
+
+  /** Commit message prompts (AI-generated commit messages) */
+  commitMessage?: CommitMessagePrompts;
 }
 
 /**
@@ -122,6 +135,7 @@ export const DEFAULT_PROMPT_CUSTOMIZATION: PromptCustomization = {
   agent: {},
   backlogPlan: {},
   enhancement: {},
+  commitMessage: {},
 };
 
 /**
@@ -155,3 +169,7 @@ export interface ResolvedEnhancementPrompts {
   acceptanceSystemPrompt: string;
   uxReviewerSystemPrompt: string;
 }
+
+export interface ResolvedCommitMessagePrompts {
+  systemPrompt: string;
+}