# Task ID: 42

**Title:** Implement prompt summary generation service

**Status:** done

**Dependencies:** 37 ✓

**Priority:** high

**Description:** Create a service that auto-generates summary (20 words) and chapters (key sections) for prompts, using fast LLM when available or regex fallback.

**Details:**

1. Create `/src/mcpd/src/services/prompt-summary.service.ts`:
   ```typescript
   export class PromptSummaryService {
     constructor(
       private llmClient: LlmClient | null,
       private promptRepo: IPromptRepository
     ) {}
     
     async generateSummary(content: string): Promise<{ summary: string; chapters: string[] }> {
       if (this.llmClient) {
         return this.generateWithLlm(content);
       }
       return this.generateWithRegex(content);
     }
     
     private async generateWithLlm(content: string): Promise<...> {
       // Send content to fast LLM with prompt:
       // "Generate a 20-word summary and extract key section topics..."
     }
     
     private generateWithRegex(content: string): { summary: string; chapters: string[] } {
       // summary: first sentence of content (truncated to ~20 words)
       // chapters: extract markdown headings via regex /^#+\s+(.+)$/gm
     }
   }
   ```

2. Integrate with PromptService:
   - Call generateSummary on prompt create
   - Call generateSummary on prompt update (when content changes)
   - Cache results on the prompt record

3. Handle LLM availability check via existing LlmConfig patterns

**Test Strategy:**

- Unit test: generateWithRegex extracts first sentence as summary
- Unit test: generateWithRegex extracts markdown headings as chapters
- Unit test: generateWithLlm calls LLM with correct prompt (mock LLM)
- Unit test: generateSummary uses LLM when available
- Unit test: generateSummary falls back to regex when no LLM
- Unit test: Empty content handled gracefully
- Unit test: Content without headings returns empty chapters array
- Integration test: Creating prompt triggers summary generation