feat(mcp): add modernize + registry_search tools, remove standalone binary

- Extract modernize rules into shared `modernize/` package for use by
  both the CLI command and MCP server
- Add `modernize` MCP tool for detecting/fixing YAML config anti-patterns
- Add `registry_search` MCP tool for querying workflow-registry plugins
- Remove duplicate `cmd/workflow-mcp-server/` binary (use `wfctl mcp`)
- Update MCP docs to reflect wfctl-only entry point

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: intel352

Makefile

@@ -1,4 +1,4 @@
-.PHONY: build build-ui build-go test bench bench-baseline bench-compare lint fmt vet fix install-hooks clean ko-build
+.PHONY: build build-ui build-go test bench bench-baseline bench-compare lint fmt vet fix install-hooks clean ko-build build-wfctl
 
 # Common benchmark flags
 BENCH_FLAGS = -bench=. -benchmem -run=^$$ -timeout=30m
@@ -18,9 +18,9 @@ build-ui:
 build-go:
 	go build -o server ./cmd/server
 
-# Build MCP server binary
-build-mcp:
-	go build -o workflow-mcp-server ./cmd/workflow-mcp-server
+# Build wfctl CLI (includes MCP server)
+build-wfctl:
+	go build -o wfctl ./cmd/wfctl
 
 # Run all tests with race detection
 test:

cmd/wfctl/mcp.go

@@ -12,6 +12,7 @@ import (
 func runMCP(args []string) error {
 	fs := flag.NewFlagSet("mcp", flag.ContinueOnError)
 	pluginDir := fs.String("plugin-dir", "data/plugins", "Plugin data directory")
+	registryDir := fs.String("registry-dir", "", "Path to cloned workflow-registry for plugin search")
 	fs.Usage = func() {
 		fmt.Fprintf(fs.Output(), `Usage: wfctl mcp [options]
 
@@ -20,7 +21,8 @@ This exposes workflow engine tools and resources to AI assistants such as
 Claude Desktop, VS Code with GitHub Copilot, and Cursor.
 
 The server provides tools for listing module types, validating configs,
-generating schemas, and inspecting workflow YAML configurations.
+generating schemas, inspecting workflow YAML configurations, modernizing
+configs (detecting/fixing anti-patterns), and searching the plugin registry.
 
 Options:
 `)
@@ -32,7 +34,7 @@ Example Claude Desktop configuration (~/.config/claude/claude_desktop_config.jso
     "mcpServers": {
       "workflow": {
         "command": "wfctl",
-        "args": ["mcp", "-plugin-dir", "/path/to/data/plugins"]
+        "args": ["mcp", "-plugin-dir", "/path/to/data/plugins", "-registry-dir", "/path/to/workflow-registry"]
       }
     }
   }
@@ -48,6 +50,11 @@ See docs/mcp.md for full setup instructions.
 	// reflect the release version set at build time.
 	workflowmcp.Version = version
 
-	srv := workflowmcp.NewServer(*pluginDir)
+	var opts []workflowmcp.ServerOption
+	if *registryDir != "" {
+		opts = append(opts, workflowmcp.WithRegistryDir(*registryDir))
+	}
+
+	srv := workflowmcp.NewServer(*pluginDir, opts...)
 	return srv.ServeStdio()
 }

cmd/wfctl/modernize.go

@@ -4,35 +4,11 @@ import (
 	"flag"
 	"fmt"
 	"os"
-	"strings"
 
+	"github.com/GoCodeAlone/workflow/modernize"
 	"gopkg.in/yaml.v3"
 )
 
-// Finding represents a single issue detected by a modernize rule.
-type Finding struct {
-	RuleID  string
-	Line    int
-	Message string
-	Fixable bool
-}
-
-// Change represents a modification applied by a rule's Fix function.
-type Change struct {
-	RuleID      string
-	Line        int
-	Description string
-}
-
-// Rule defines a modernize transformation rule.
-type Rule struct {
-	ID          string
-	Description string
-	Severity    string // "error" or "warning"
-	Check       func(root *yaml.Node, raw []byte) []Finding
-	Fix         func(root *yaml.Node) []Change
-}
-
 func runModernize(args []string) error {
 	fs := flag.NewFlagSet("modernize", flag.ContinueOnError)
 	apply := fs.Bool("apply", false, "Apply fixes in-place (default: dry-run)")
@@ -64,7 +40,7 @@ Options:
 		return err
 	}
 
-	rules := allModernizeRules()
+	rules := modernize.AllRules()
 
 	if *listRules {
 		fmt.Println("Available modernize rules:")
@@ -80,7 +56,7 @@ Options:
 	}
 
 	// Filter rules
-	rules = filterRules(rules, *rulesFlag, *excludeFlag)
+	rules = modernize.FilterRules(rules, *rulesFlag, *excludeFlag)
 
 	// Collect files
 	var files []string
@@ -145,7 +121,7 @@ Options:
 }
 
 // modernizeFile checks (and optionally fixes) a single YAML file.
-func modernizeFile(path string, rules []Rule, apply bool) ([]Finding, int, error) {
+func modernizeFile(path string, rules []modernize.Rule, apply bool) ([]modernize.Finding, int, error) {
 	data, err := os.ReadFile(path)
 	if err != nil {
 		return nil, 0, err
@@ -157,7 +133,7 @@ func modernizeFile(path string, rules []Rule, apply bool) ([]Finding, int, error
 	}
 
 	// Check phase
-	var allFindings []Finding
+	var allFindings []modernize.Finding
 	for _, r := range rules {
 		findings := r.Check(&doc, data)
 		allFindings = append(allFindings, findings...)
@@ -189,36 +165,3 @@ func modernizeFile(path string, rules []Rule, apply bool) ([]Finding, int, error
 
 	return allFindings, fixCount, nil
 }
-
-// filterRules filters the rule list based on include/exclude flags.
-func filterRules(rules []Rule, include, exclude string) []Rule {
-	if include == "" && exclude == "" {
-		return rules
-	}
-
-	includeSet := make(map[string]bool)
-	if include != "" {
-		for _, id := range strings.Split(include, ",") {
-			includeSet[strings.TrimSpace(id)] = true
-		}
-	}
-
-	excludeSet := make(map[string]bool)
-	if exclude != "" {
-		for _, id := range strings.Split(exclude, ",") {
-			excludeSet[strings.TrimSpace(id)] = true
-		}
-	}
-
-	var filtered []Rule
-	for _, r := range rules {
-		if len(includeSet) > 0 && !includeSet[r.ID] {
-			continue
-		}
-		if excludeSet[r.ID] {
-			continue
-		}
-		filtered = append(filtered, r)
-	}
-	return filtered
-}

cmd/wfctl/modernize_test.go

@@ -5,6 +5,7 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/GoCodeAlone/workflow/modernize"
 	"gopkg.in/yaml.v3"
 )
 
@@ -25,37 +26,37 @@ func TestRunModernize_NoFiles(t *testing.T) {
 }
 
 func TestFilterRules_Empty(t *testing.T) {
-	rules := []Rule{
+	rules := []modernize.Rule{
 		{ID: "rule-a", Description: "A"},
 		{ID: "rule-b", Description: "B"},
 	}
 
 	// No filters — all rules returned
-	result := filterRules(rules, "", "")
+	result := modernize.FilterRules(rules, "", "")
 	if len(result) != 2 {
 		t.Fatalf("expected 2 rules, got %d", len(result))
 	}
 }
 
 func TestFilterRules_Include(t *testing.T) {
-	rules := []Rule{
+	rules := []modernize.Rule{
 		{ID: "rule-a", Description: "A"},
 		{ID: "rule-b", Description: "B"},
 	}
 
-	result := filterRules(rules, "rule-a", "")
+	result := modernize.FilterRules(rules, "rule-a", "")
 	if len(result) != 1 || result[0].ID != "rule-a" {
 		t.Fatalf("expected only rule-a, got %v", result)
 	}
 }
 
 func TestFilterRules_Exclude(t *testing.T) {
-	rules := []Rule{
+	rules := []modernize.Rule{
 		{ID: "rule-a", Description: "A"},
 		{ID: "rule-b", Description: "B"},
 	}
 
-	result := filterRules(rules, "", "rule-b")
+	result := modernize.FilterRules(rules, "", "rule-b")
 	if len(result) != 1 || result[0].ID != "rule-a" {
 		t.Fatalf("expected only rule-a, got %v", result)
 	}
@@ -69,7 +70,7 @@ func TestModernizeFile_ValidYAML(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	findings, fixes, err := modernizeFile(tmpFile, []Rule{}, false)
+	findings, fixes, err := modernizeFile(tmpFile, []modernize.Rule{}, false)
 	if err != nil {
 		t.Fatalf("unexpected error: %v", err)
 	}
@@ -88,7 +89,7 @@ func TestModernizeFile_InvalidYAML(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	_, _, err := modernizeFile(tmpFile, []Rule{}, false)
+	_, _, err := modernizeFile(tmpFile, []modernize.Rule{}, false)
 	if err == nil {
 		t.Fatal("expected error for invalid YAML")
 	}
@@ -108,8 +109,8 @@ func parseTestYAML(t *testing.T, input string) *yaml.Node {
 }
 
 // findRule is a test helper that looks up a rule by ID.
-func findRule(id string) *Rule {
-	for _, r := range allModernizeRules() {
+func findRule(id string) *modernize.Rule {
+	for _, r := range modernize.AllRules() {
 		if r.ID == id {
 			return &r
 		}
@@ -185,8 +186,8 @@ pipelines:
         config:
           field: steps.check-xss.matched
 `
-	rules := allModernizeRules()
-	var rule Rule
+	rules := modernize.AllRules()
+	var rule modernize.Rule
 	for _, r := range rules {
 		if r.ID == "hyphen-steps" {
 			rule = r
@@ -230,8 +231,8 @@ pipelines:
           body:
             value: "{{ .steps.check-xss.result }}"
 `
-	rules := allModernizeRules()
-	var rule Rule
+	rules := modernize.AllRules()
+	var rule modernize.Rule
 	for _, r := range rules {
 		if r.ID == "hyphen-steps" {
 			rule = r
@@ -483,7 +484,7 @@ modules:
 }
 
 func TestModernizeAllRulesRegistered(t *testing.T) {
-	rules := allModernizeRules()
+	rules := modernize.AllRules()
 	expectedIDs := []string{
 		"hyphen-steps",
 		"conditional-field",
@@ -508,16 +509,16 @@ func TestModernizeAllRulesRegistered(t *testing.T) {
 }
 
 func TestFilterRulesIntegration(t *testing.T) {
-	rules := allModernizeRules()
+	rules := modernize.AllRules()
 
 	// Include filter
-	filtered := filterRules(rules, "hyphen-steps,empty-routes", "")
+	filtered := modernize.FilterRules(rules, "hyphen-steps,empty-routes", "")
 	if len(filtered) != 2 {
 		t.Errorf("expected 2 rules with include filter, got %d", len(filtered))
 	}
 
 	// Exclude filter
-	filtered = filterRules(rules, "", "camelcase-config")
+	filtered = modernize.FilterRules(rules, "", "camelcase-config")
 	if len(filtered) != len(rules)-1 {
 		t.Errorf("expected %d rules with exclude filter, got %d", len(rules)-1, len(filtered))
 	}
@@ -553,11 +554,11 @@ pipelines:
           body:
             name: "{{ .steps.fetch.row.name }}"
 `
-	rules := allModernizeRules()
+	rules := modernize.AllRules()
 	doc := parseTestYAML(t, input)
 
 	// Check phase
-	var allFindings []Finding
+	var allFindings []modernize.Finding
 	for _, r := range rules {
 		allFindings = append(allFindings, r.Check(doc, []byte(input))...)
 	}