feat(api): chatbot-facing MCP server for task orchestration (Phase 3)

Adds a chatbot-facing MCP server mounted at /chatbot/mcp, guarded by the shared
API bearer token (new config api_token, wired through SetAPIToken). Tools:
submit_task, list_tasks, get_task, get_events, answer_question, accept_task,
reject_task, cancel_task. submit_task creates and immediately queues a task,
resolving the repository URL from a named project when not given explicitly.

To keep the REST API and the MCP surface from drifting, the accept/reject/
cancel/answer operations are extracted into a shared service layer (taskops.go)
with typed errors mapped to REST status codes; the existing HTTP handlers now
delegate to it. The endpoint is only served when a token is configured and
presented as a bearer.

https://claude.ai/code/session_01SESwn7kQ7oP62trWw6pc39

1 files changed, 233 insertions, 0 deletions

diff --git a/internal/api/chatbotmcp_test.go b/internal/api/chatbotmcp_test.go
new file mode 100644
index 0000000..d13b0d7
--- /dev/null
+++ b/internal/api/chatbotmcp_test.go
@@ -0,0 +1,233 @@
+package api
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/modelcontextprotocol/go-sdk/mcp"
+	"github.com/thepeterstone/claudomator/internal/storage"
+	"github.com/thepeterstone/claudomator/internal/task"
+)
+
+// chatbotClient starts the api server with the given token and returns a
+// connected MCP client session pointed at /chatbot/mcp.
+func chatbotClient(t *testing.T, srv *Server, token string) *mcp.ClientSession {
+	t.Helper()
+	ts := httptest.NewServer(srv.Handler())
+	t.Cleanup(ts.Close)
+
+	client := mcp.NewClient(&mcp.Implementation{Name: "test", Version: "1"}, nil)
+	cs, err := client.Connect(context.Background(), &mcp.StreamableClientTransport{
+		Endpoint:   ts.URL + "/chatbot/mcp",
+		HTTPClient: &http.Client{Transport: tokenRT{token: token, base: http.DefaultTransport}},
+	}, nil)
+	if err != nil {
+		t.Fatalf("connect to /chatbot/mcp: %v", err)
+	}
+	t.Cleanup(func() { cs.Close() })
+	return cs
+}
+
+func callText(t *testing.T, cs *mcp.ClientSession, name string, args map[string]any) string {
+	t.Helper()
+	res, err := cs.CallTool(context.Background(), &mcp.CallToolParams{Name: name, Arguments: args})
+	if err != nil {
+		t.Fatalf("CallTool %s transport error: %v", name, err)
+	}
+	if res.IsError {
+		t.Fatalf("CallTool %s returned tool error: %s", name, toolText(res))
+	}
+	return toolText(res)
+}
+
+func toolText(res *mcp.CallToolResult) string {
+	if len(res.Content) == 0 {
+		return ""
+	}
+	if tc, ok := res.Content[0].(*mcp.TextContent); ok {
+		return tc.Text
+	}
+	return ""
+}
+
+func TestChatbotMCP_RequiresToken(t *testing.T) {
+	srv, _ := testServer(t)
+	srv.SetAPIToken("s3cret")
+	ts := httptest.NewServer(srv.Handler())
+	defer ts.Close()
+
+	client := mcp.NewClient(&mcp.Implementation{Name: "test", Version: "1"}, nil)
+	_, err := client.Connect(context.Background(), &mcp.StreamableClientTransport{
+		Endpoint:   ts.URL + "/chatbot/mcp",
+		HTTPClient: &http.Client{Transport: tokenRT{token: "wrong", base: http.DefaultTransport}},
+	}, nil)
+	if err == nil {
+		t.Fatal("expected connect with wrong token to be rejected")
+	}
+}
+
+func TestChatbotMCP_SubmitTask_CreatesAndQueues(t *testing.T) {
+	srv, store := testServer(t)
+	srv.SetAPIToken("s3cret")
+	cs := chatbotClient(t, srv, "s3cret")
+
+	out := callText(t, cs, "submit_task", map[string]any{
+		"instructions":   "fix the flaky test in package foo",
+		"repository_url": "https://github.com/user/repo",
+	})
+	var ct compactTask
+	if err := json.Unmarshal([]byte(out), &ct); err != nil {
+		t.Fatalf("unmarshal submit_task result %q: %v", out, err)
+	}
+	if ct.ID == "" {
+		t.Fatal("submit_task returned empty task ID")
+	}
+	if ct.Name != "fix the flaky test in package foo" {
+		t.Errorf("name defaulted wrong: %q", ct.Name)
+	}
+	if _, err := store.GetTask(ct.ID); err != nil {
+		t.Fatalf("submitted task not persisted: %v", err)
+	}
+}
+
+func TestChatbotMCP_SubmitTask_RequiresRepo(t *testing.T) {
+	srv, _ := testServer(t)
+	srv.SetAPIToken("s3cret")
+	cs := chatbotClient(t, srv, "s3cret")
+
+	res, err := cs.CallTool(context.Background(), &mcp.CallToolParams{
+		Name:      "submit_task",
+		Arguments: map[string]any{"instructions": "do a thing"},
+	})
+	if err != nil {
+		t.Fatalf("transport error: %v", err)
+	}
+	if !res.IsError {
+		t.Fatal("expected submit_task without repository_url to be a tool error")
+	}
+}
+
+func TestChatbotMCP_GetAndListTasks(t *testing.T) {
+	srv, store := testServer(t)
+	srv.SetAPIToken("s3cret")
+	createTaskWithState(t, store, "ct-ready", task.StateReady)
+	cs := chatbotClient(t, srv, "s3cret")
+
+	got := callText(t, cs, "get_task", map[string]any{"task_id": "ct-ready"})
+	var view map[string]any
+	if err := json.Unmarshal([]byte(got), &view); err != nil {
+		t.Fatalf("unmarshal get_task: %v", err)
+	}
+	if view["id"] != "ct-ready" {
+		t.Errorf("get_task id: got %v", view["id"])
+	}
+
+	listed := callText(t, cs, "list_tasks", map[string]any{"state": "READY"})
+	var tasks []compactTask
+	if err := json.Unmarshal([]byte(listed), &tasks); err != nil {
+		t.Fatalf("unmarshal list_tasks: %v", err)
+	}
+	if len(tasks) != 1 || tasks[0].ID != "ct-ready" {
+		t.Errorf("list_tasks returned %+v", tasks)
+	}
+}
+
+func TestChatbotMCP_GetTask_NotFound(t *testing.T) {
+	srv, _ := testServer(t)
+	srv.SetAPIToken("s3cret")
+	cs := chatbotClient(t, srv, "s3cret")
+
+	res, err := cs.CallTool(context.Background(), &mcp.CallToolParams{
+		Name:      "get_task",
+		Arguments: map[string]any{"task_id": "nope"},
+	})
+	if err != nil {
+		t.Fatalf("transport error: %v", err)
+	}
+	if !res.IsError {
+		t.Fatal("expected get_task on missing task to be a tool error")
+	}
+}
+
+func TestChatbotMCP_GetEvents(t *testing.T) {
+	srv, store := testServer(t)
+	srv.SetAPIToken("s3cret")
+	createTaskWithState(t, store, "ct-events", task.StateReady)
+	cs := chatbotClient(t, srv, "s3cret")
+
+	out := callText(t, cs, "get_events", map[string]any{"task_id": "ct-events"})
+	var events []map[string]any
+	if err := json.Unmarshal([]byte(out), &events); err != nil {
+		t.Fatalf("unmarshal get_events %q: %v", out, err)
+	}
+	// State walk to READY emits state_change events.
+	if len(events) == 0 {
+		t.Error("expected at least one event for a task that walked to READY")
+	}
+}
+
+func TestChatbotMCP_AcceptTask(t *testing.T) {
+	srv, store := testServer(t)
+	srv.SetAPIToken("s3cret")
+	createTaskWithState(t, store, "ct-accept", task.StateReady)
+	cs := chatbotClient(t, srv, "s3cret")
+
+	callText(t, cs, "accept_task", map[string]any{"task_id": "ct-accept"})
+	got, _ := store.GetTask("ct-accept")
+	if got.State != task.StateCompleted {
+		t.Errorf("after accept_task: want COMPLETED, got %s", got.State)
+	}
+}
+
+func TestChatbotMCP_RejectTask(t *testing.T) {
+	srv, store := testServer(t)
+	srv.SetAPIToken("s3cret")
+	createTaskWithState(t, store, "ct-reject", task.StateReady)
+	cs := chatbotClient(t, srv, "s3cret")
+
+	callText(t, cs, "reject_task", map[string]any{"task_id": "ct-reject", "comment": "needs work"})
+	got, _ := store.GetTask("ct-reject")
+	if got.State != task.StatePending {
+		t.Errorf("after reject_task: want PENDING, got %s", got.State)
+	}
+	if got.RejectionComment != "needs work" {
+		t.Errorf("rejection comment: got %q", got.RejectionComment)
+	}
+}
+
+func TestChatbotMCP_CancelTask(t *testing.T) {
+	srv, store := testServer(t)
+	srv.SetAPIToken("s3cret")
+	createTaskWithState(t, store, "ct-cancel", task.StateQueued)
+	cs := chatbotClient(t, srv, "s3cret")
+
+	callText(t, cs, "cancel_task", map[string]any{"task_id": "ct-cancel"})
+	got, _ := store.GetTask("ct-cancel")
+	if got.State != task.StateCancelled {
+		t.Errorf("after cancel_task: want CANCELLED, got %s", got.State)
+	}
+}
+
+func TestChatbotMCP_AnswerQuestion(t *testing.T) {
+	srv, store := testServer(t)
+	srv.SetAPIToken("s3cret")
+	createTaskWithState(t, store, "ct-answer", task.StateBlocked)
+	if err := store.CreateExecution(&storage.Execution{
+		ID:        "ct-answer-exec",
+		TaskID:    "ct-answer",
+		SessionID: "550e8400-e29b-41d4-a716-446655440099",
+		Status:    "BLOCKED",
+	}); err != nil {
+		t.Fatalf("create execution: %v", err)
+	}
+	cs := chatbotClient(t, srv, "s3cret")
+
+	callText(t, cs, "answer_question", map[string]any{"task_id": "ct-answer", "answer": "use main"})
+	got, _ := store.GetTask("ct-answer")
+	if got.State != task.StateQueued && got.State != task.StateRunning && got.State != task.StateReady {
+		t.Errorf("after answer_question: want QUEUED/RUNNING/READY, got %s", got.State)
+	}
+}