feat: add TDD skill with red/green/refactor handlers

internal/skills/tdd/skill.go

@@ -0,0 +1,84 @@
+package tdd
+
+import (
+	"context"
+	"encoding/json"
+
+	iexec "github.com/mathiasbq/supervisor/internal/exec"
+	"github.com/mathiasbq/supervisor/internal/registry"
+)
+
+// ExecutorFn allows injecting a test double for the executor.
+type ExecutorFn func(ctx context.Context, req iexec.Request) (iexec.Result, error)
+
+type Config struct {
+	SystemPrompt string
+	SkillPrompt  string
+	ExecutorFn   ExecutorFn // nil = no executor (tests that don't reach execute())
+	DefaultModel string
+}
+
+type Skill struct {
+	cfg Config
+}
+
+func New(cfg Config) *Skill {
+	return &Skill{cfg: cfg}
+}
+
+func (s *Skill) Name() string { return "tdd" }
+
+func (s *Skill) Tools() []registry.ToolDef {
+	schema := func(required []string, props map[string]any) json.RawMessage {
+		b, _ := json.Marshal(map[string]any{
+			"type":       "object",
+			"required":   required,
+			"properties": props,
+		})
+		return b
+	}
+	strProp := map[string]any{"type": "string"}
+
+	return []registry.ToolDef{
+		{
+			Name:        "tdd_red",
+			Description: "Write a failing test for the described behavior. Verifies the test fails before returning.",
+			InputSchema: schema(
+				[]string{"project_root", "spec"},
+				map[string]any{
+					"project_root": strProp,
+					"spec":         strProp,
+					"model":        strProp,
+					"test_cmd":     strProp,
+				},
+			),
+		},
+		{
+			Name:        "tdd_green",
+			Description: "Write minimal implementation to make the test at test_path pass.",
+			InputSchema: schema(
+				[]string{"project_root", "test_path"},
+				map[string]any{
+					"project_root": strProp,
+					"test_path":    strProp,
+					"model":        strProp,
+					"test_cmd":     strProp,
+				},
+			),
+		},
+		{
+			Name:        "tdd_refactor",
+			Description: "Refactor the implementation at impl_path while keeping tests green.",
+			InputSchema: schema(
+				[]string{"project_root", "test_path", "impl_path"},
+				map[string]any{
+					"project_root": strProp,
+					"test_path":    strProp,
+					"impl_path":    strProp,
+					"model":        strProp,
+					"test_cmd":     strProp,
+				},
+			),
+		},
+	}
+}