feat: add design_prompt meta-prompt for implementation planningv0.21.0

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

2 files changed, 32 insertions, 5 deletions

diff --git a/internal/promptstore/default_prompts.go b/internal/promptstore/default_prompts.go
index acfbe9a..f8edefc 100644
--- a/internal/promptstore/default_prompts.go
+++ b/internal/promptstore/default_prompts.go
@@ -6,8 +6,8 @@ import (
 )
 
 // DefaultPrompts returns the built-in meta-prompts for prompt management.
-// These prompts help users create and update prompts interactively using Claude's
-// access to conversation context.
+// These prompts help users create, update, delete, and design prompts interactively
+// using Claude's access to conversation context.
 func DefaultPrompts() []Prompt {
 	now := time.Now()
 
@@ -181,5 +181,32 @@ Ask me to confirm the deletion of '{{prompt_name}}'.`,
 			Created: now,
 			Updated: now,
 		},
+		{
+			Name:        "design_prompt",
+			Title:       "Design New Prompt from Scratch",
+			Description: "Interactively design a brand new prompt template through guided questions. Claude will help you define the purpose, arguments, message flow, and metadata step by step, show a preview, and wait for approval before saving.",
+			Arguments:   []PromptArgument{},
+			Messages: []PromptMessage{
+				{
+					Role: "user",
+					Content: MessageContent{
+						Type: "text",
+						Text: `I want to design a brand new prompt template from scratch.
+
+Please ask me:
+1) What should this prompt do? (describe the task/purpose in 1-2 sentences)
+2) What arguments does it need? (if any - use {{argument}} syntax)
+3) Prompt name (lowercase, underscores only), title, and tags
+
+Then show me a preview and save it after I approve.
+
+Keep questions brief and focused.`,
+					},
+				},
+			},
+			Tags:    []string{"meta", "prompt-management", "interactive", "creation"},
+			Created: now,
+			Updated: now,
+		},
 	}
 }
diff --git a/internal/promptstore/store_test.go b/internal/promptstore/store_test.go
index 2c95ad7..1ec784a 100644
--- a/internal/promptstore/store_test.go
+++ b/internal/promptstore/store_test.go
@@ -84,9 +84,9 @@ func TestJSONLStore_List(t *testing.T) {
 		t.Fatalf("List() error = %v", err)
 	}
 
-	// Should have all prompts (7 user + 3 built-ins)
-	if len(prompts) != 10 {
-		t.Errorf("List() got %d prompts, want 10 (7 user + 3 built-ins)", len(prompts))
+	// Should have all prompts (7 user + 4 built-ins)
+	if len(prompts) != 11 {
+		t.Errorf("List() got %d prompts, want 11 (7 user + 4 built-ins)", len(prompts))
 	}
 
 	// No cursor for full list