Add Prompt field to Result struct combining rules and task content (#169)

* Initial plan

* Add Prompt field to Result struct with combined rules and task content

Co-authored-by: alexec <1142830+alexec@users.noreply.github.com>

* Fix output formatting to match original behavior with trailing newline

Co-authored-by: alexec <1142830+alexec@users.noreply.github.com>

* Fix TestResult_Prompt to actually test Context.Run() behavior

The test now creates temporary files and calls Context.Run() to verify
that the Prompt field is correctly populated by the context assembly logic,
instead of manually setting the Prompt field and checking it equals itself.

Co-authored-by: alexec <1142830+alexec@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: alexec <1142830+alexec@users.noreply.github.com>
Co-authored-by: Alex Collins <alexec@users.noreply.github.com>

Author: Copilot

main.go

@@ -166,12 +166,7 @@ func main() {
 			fmt.Println("---")
 		}
 
-		// Output all rules
-		for _, rule := range result.Rules {
-			fmt.Println(rule.Content)
-		}
-
-		// Output task
-		fmt.Println(result.Task.Content)
+		// Output the combined prompt (rules + task)
+		fmt.Println(result.Prompt)
 	}
 }

pkg/codingcontext/context.go

@@ -328,12 +328,21 @@ func (cc *Context) Run(ctx context.Context, taskName string) (*Result, error) {
 	// Estimate tokens for task
 	cc.logger.Info("Total estimated tokens", "tokens", cc.totalTokens)
 
+	// Build the combined prompt from all rules and task content
+	var promptBuilder strings.Builder
+	for _, rule := range cc.rules {
+		promptBuilder.WriteString(rule.Content)
+		promptBuilder.WriteString("\n")
+	}
+	promptBuilder.WriteString(cc.task.Content)
+
 	// Build and return the result
 	result := &Result{
 		Rules:  cc.rules,
 		Task:   cc.task,
 		Tokens: cc.totalTokens,
 		Agent:  cc.agent,
+		Prompt: promptBuilder.String(),
 	}
 
 	return result, nil

pkg/codingcontext/result.go

@@ -11,6 +11,7 @@ type Result struct {
 	Task   markdown.Markdown[markdown.TaskFrontMatter]   // Task file with frontmatter and content
 	Tokens int                                           // Total token count
 	Agent  Agent                                         // The agent used (from task or -a flag)
+	Prompt string                                        // Combined prompt: all rules and task content
 }
 
 // MCPServers returns all MCP server configurations from rules.

pkg/codingcontext/result_test.go

@@ -1,12 +1,73 @@
 package codingcontext
 
 import (
+	"context"
+	"log/slog"
+	"os"
 	"testing"
 
 	"github.com/kitproj/coding-context-cli/pkg/codingcontext/markdown"
 	"github.com/kitproj/coding-context-cli/pkg/codingcontext/mcp"
 )
 
+func TestResult_Prompt(t *testing.T) {
+	tests := []struct {
+		name     string
+		setup    func(t *testing.T, dir string)
+		taskName string
+		want     string
+	}{
+		{
+			name: "task only without rules",
+			setup: func(t *testing.T, dir string) {
+				createTask(t, dir, "test-task", "task_name: test-task", "Task content\n")
+			},
+			taskName: "test-task",
+			want:     "Task content\n",
+		},
+		{
+			name: "single rule and task",
+			setup: func(t *testing.T, dir string) {
+				createTask(t, dir, "test-task", "task_name: test-task", "Task content\n")
+				createRule(t, dir, ".agents/rules/rule1.md", "", "Rule 1 content\n")
+			},
+			taskName: "test-task",
+			want:     "Rule 1 content\n\nTask content\n",
+		},
+		{
+			name: "multiple rules and task",
+			setup: func(t *testing.T, dir string) {
+				createTask(t, dir, "test-task", "task_name: test-task", "Task content\n")
+				createRule(t, dir, ".agents/rules/rule1.md", "", "Rule 1 content\n")
+				createRule(t, dir, ".agents/rules/rule2.md", "", "Rule 2 content\n")
+			},
+			taskName: "test-task",
+			want:     "Rule 1 content\n\nRule 2 content\n\nTask content\n",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			tmpDir := t.TempDir()
+			tt.setup(t, tmpDir)
+
+			ctx := New(
+				WithSearchPaths("file://"+tmpDir),
+				WithLogger(slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{Level: slog.LevelError}))),
+			)
+
+			result, err := ctx.Run(context.Background(), tt.taskName)
+			if err != nil {
+				t.Fatalf("Run() error = %v", err)
+			}
+
+			if result.Prompt != tt.want {
+				t.Errorf("Result.Prompt = %q, want %q", result.Prompt, tt.want)
+			}
+		})
+	}
+}
+
 func TestResult_MCPServers(t *testing.T) {
 	tests := []struct {
 		name   string