Add mcp UI resource and codemode (#179)

* add mcp-ui example
* add codemode example
* add mcp-discover prompt

Author: slimslenderslacks

go.mod

@@ -11,6 +11,7 @@ require (
 	github.com/docker/cli-docs-tool v0.10.0
 	github.com/docker/docker v28.2.2+incompatible
 	github.com/docker/docker-credential-helpers v0.9.3
+	github.com/dop251/goja v0.0.0-20251008123653-cf18d89f3cf6
 	github.com/fsnotify/fsnotify v1.9.0
 	github.com/google/go-containerregistry v0.20.6
 	github.com/google/jsonschema-go v0.3.0
@@ -35,6 +36,12 @@ require (
 	gopkg.in/yaml.v3 v3.0.1
 )
 
+require (
+	github.com/dlclark/regexp2 v1.11.4 // indirect
+	github.com/go-sourcemap/sourcemap v2.1.3+incompatible // indirect
+	github.com/google/pprof v0.0.0-20241210010833-40e02aabc2ad // indirect
+)
+
 require (
 	github.com/Azure/go-ansiterm v0.0.0-20250102033503-faa5f7b0171c // indirect
 	github.com/PaesslerAG/gval v1.2.4 // indirect
@@ -116,7 +123,7 @@ require (
 	github.com/onsi/gomega v1.37.0 // indirect
 	github.com/open-policy-agent/opa v1.5.1 // indirect
 	github.com/opentracing/opentracing-go v1.2.0 // indirect
-	github.com/pelletier/go-toml/v2 v2.2.4 // indirect
+	github.com/pelletier/go-toml/v2 v2.2.4
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
 	github.com/prometheus/client_model v0.6.2 // indirect
 	github.com/rivo/uniseg v0.4.7 // indirect

go.sum

@@ -55,6 +55,8 @@ github.com/Azure/go-autorest/tracing v0.6.0/go.mod h1:+vhtPC754Xsa23ID7GlGsrdKBp
 github.com/AzureAD/microsoft-authentication-library-for-go v1.4.2 h1:oygO0locgZJe7PpYPXT5A29ZkwJaPqcva7BVeemZOZs=
 github.com/AzureAD/microsoft-authentication-library-for-go v1.4.2/go.mod h1:wP83P5OoQ5p6ip3ScPr0BAq0BvuPAvacpEuSzyouqAI=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
+github.com/Masterminds/semver/v3 v3.2.1 h1:RN9w6+7QoMeJVGyfmbcgs28Br8cvmnucEXnY0rYXWg0=
+github.com/Masterminds/semver/v3 v3.2.1/go.mod h1:qvl/7zhW3nngYb5+80sSMF+FG2BjYrf8m9wsX0PNOMQ=
 github.com/Microsoft/go-winio v0.6.2 h1:F2VQgta7ecxGYO8k3ZZz3RS8fVIXVxONVUPlNERoyfY=
 github.com/Microsoft/go-winio v0.6.2/go.mod h1:yd8OoFMLzJbo9gZq8j5qaps8bJ9aShtEA8Ipt1oGCvU=
 github.com/PaesslerAG/gval v1.0.0/go.mod h1:y/nm5yEyTeX6av0OfKJNp9rBNj2XrGhAf5+v24IBN1I=
@@ -218,6 +220,8 @@ github.com/dimchansky/utfbom v1.1.1 h1:vV6w1AhK4VMnhBno/TPVCoK9U/LP0PkLCS9tbxHdi
 github.com/dimchansky/utfbom v1.1.1/go.mod h1:SxdoEBH5qIqFocHMyGOXVAybYJdr71b1Q/j0mACtrfE=
 github.com/distribution/reference v0.6.0 h1:0IXCQ5g4/QMHHkarYzh5l+u8T3t73zM5QvfrDyIgxBk=
 github.com/distribution/reference v0.6.0/go.mod h1:BbU0aIcezP1/5jX/8MP0YiH4SdvB5Y4f/wlDRiLyi3E=
+github.com/dlclark/regexp2 v1.11.4 h1:rPYF9/LECdNymJufQKmri9gV604RvvABwgOA8un7yAo=
+github.com/dlclark/regexp2 v1.11.4/go.mod h1:DHkYz0B9wPfa6wondMfaivmHpzrQ3v9q8cnmRbL6yW8=
 github.com/docker/cli v28.2.2+incompatible h1:qzx5BNUDFqlvyq4AHzdNB7gSyVTmU4cgsyN9SdInc1A=
 github.com/docker/cli v28.2.2+incompatible/go.mod h1:JLrzqnKDaYBop7H2jaqPtU4hHvMKP+vjCwu2uszcLI8=
 github.com/docker/cli-docs-tool v0.10.0 h1:bOD6mKynPQgojQi3s2jgcUWGp/Ebqy1SeCr9VfKQLLU=
@@ -240,6 +244,8 @@ github.com/docker/go-metrics v0.0.1/go.mod h1:cG1hvH2utMXtqgqqYE9plW6lDxS3/5ayHz
 github.com/docker/go-units v0.5.0 h1:69rxXcBk27SvSaaxTtLh/8llcHD8vYHT7WSdRZ/jvr4=
 github.com/docker/go-units v0.5.0/go.mod h1:fgPhTUdO+D/Jk86RDLlptpiXQzgHJF7gydDDbaIK4Dk=
 github.com/docker/libtrust v0.0.0-20160708172513-aabc10ec26b7/go.mod h1:cyGadeNEkKy96OOhEzfZl+yxihPEzKnqJwvfuSUqbZE=
+github.com/dop251/goja v0.0.0-20251008123653-cf18d89f3cf6 h1:6dE1TmjqkY6tehR4A67gDNhvDtuZ54ocu7ab4K9o540=
+github.com/dop251/goja v0.0.0-20251008123653-cf18d89f3cf6/go.mod h1:MxLav0peU43GgvwVgNbLAj1s/bSGboKkhuULvq/7hx4=
 github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
 github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
 github.com/dvsekhvalnov/jose2go v0.0.0-20170216131308-f21a8cedbbae/go.mod h1:7BvyPhdbLxMXIYTFPLsyJRFMsKmOZnQmzh6Gb+uquuM=
@@ -303,6 +309,8 @@ github.com/go-openapi/validate v0.24.0 h1:LdfDKwNbpB6Vn40xhTdNZAnfLECL81w+VX3Bum
 github.com/go-openapi/validate v0.24.0/go.mod h1:iyeX1sEufmv3nPbBdX3ieNviWnOZaJ1+zquzJEf2BAQ=
 github.com/go-piv/piv-go/v2 v2.3.0 h1:kKkrYlgLQTMPA6BiSL25A7/x4CEh2YCG7rtb/aTkx+g=
 github.com/go-piv/piv-go/v2 v2.3.0/go.mod h1:ShZi74nnrWNQEdWzRUd/3cSig3uNOcEZp+EWl0oewnI=
+github.com/go-sourcemap/sourcemap v2.1.3+incompatible h1:W1iEw64niKVGogNgBN3ePyLFfuisuzeidWPMPWmECqU=
+github.com/go-sourcemap/sourcemap v2.1.3+incompatible/go.mod h1:F8jJfvm2KbVjc5NqelyYJmf/v5J0dwNLS2mL4sNA1Jg=
 github.com/go-sql-driver/mysql v1.5.0/go.mod h1:DCzpHaOWr8IXmIStZouvnhqoel9Qv2LBy8hT2VhHyBg=
 github.com/go-sql-driver/mysql v1.9.2 h1:4cNKDYQ1I84SXslGddlsrMhc8k4LeDVj6Ad6WRjiHuU=
 github.com/go-sql-driver/mysql v1.9.2/go.mod h1:qn46aNg1333BRMNU69Lq93t8du/dwxI64Gl8i5p1WMU=
@@ -369,6 +377,8 @@ github.com/google/gofuzz v1.2.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/
 github.com/google/jsonschema-go v0.3.0 h1:6AH2TxVNtk3IlvkkhjrtbUc4S8AvO0Xii0DxIygDg+Q=
 github.com/google/jsonschema-go v0.3.0/go.mod h1:r5quNTdLOYEz95Ru18zA0ydNbBuYoo9tgaYcxEYhJVE=
 github.com/google/pprof v0.0.0-20210407192527-94a9f03dee38/go.mod h1:kpwsk12EmLew5upagYY7GY0pfYCcupk39gWOCRROcvE=
+github.com/google/pprof v0.0.0-20241210010833-40e02aabc2ad h1:a6HEuzUHeKH6hwfN/ZoQgRgVIWFJljSWa/zetS2WTvg=
+github.com/google/pprof v0.0.0-20241210010833-40e02aabc2ad/go.mod h1:vavhavw2zAxS5dIdcRluK6cSGGPlZynqzFM8NdvU144=
 github.com/google/s2a-go v0.1.9 h1:LGD7gtMgezd8a/Xak7mEWL0PjoTQFvpRudN895yqKW0=
 github.com/google/s2a-go v0.1.9/go.mod h1:YA0Ei2ZQL3acow2O62kdp9UlnvMmU7kA6Eutn0dXayM=
 github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510 h1:El6M4kTTCOh6aBiKaUGG7oYTSPP8MxqL4YI3kZKwcP4=
@@ -903,6 +913,7 @@ gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.3.0/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
 gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=

pkg/codemode/codemode.go

@@ -0,0 +1,107 @@
+package codemode
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"strings"
+
+	"github.com/modelcontextprotocol/go-sdk/mcp"
+)
+
+const Prompt = `Run a Javascript script to call MCP tools.
+
+Instead of calling individual tools directly, use this to write a Javascript script that calls as many tools as needed.
+This allows you to combine multiple tool calls in a single request, perform conditional logic,
+and manipulate the results before returning them.
+
+Instructions:
+ - The script has access to all the tools as plain javascript functions.
+ - "await"/"async" are never needed. All the tool calls are synchronous.
+ - Every tool function returns a string result.
+ - The script must return a string result.
+
+Available tools/functions:
+
+`
+
+type RunToolsWithJavascriptArgs struct {
+	Script string `json:"script"`
+}
+
+// ToolSet represents a collection of MCP tools with lifecycle management
+type ToolSet interface {
+	Tools(ctx context.Context) ([]*ToolWithHandler, error)
+}
+
+// ToolWithHandler combines an MCP Tool definition with its handler function
+type ToolWithHandler struct {
+	Tool    *mcp.Tool
+	Handler mcp.ToolHandler
+}
+
+type tool struct {
+	toolsets []ToolSet
+}
+
+func (c *tool) Tools(ctx context.Context) ([]*ToolWithHandler, error) {
+	var functionsDoc []string
+
+	for _, toolset := range c.toolsets {
+		allTools, err := toolset.Tools(ctx)
+		if err != nil {
+			return nil, err
+		}
+
+		for _, tool := range allTools {
+			functionsDoc = append(functionsDoc, toolToJsDoc(tool.Tool))
+		}
+	}
+
+	description := Prompt + strings.Join(functionsDoc, "\n")
+
+	jstool := &ToolWithHandler{
+		Tool: &mcp.Tool{
+			Name:        "run_tools_with_javascript",
+			Description: description,
+			Annotations: &mcp.ToolAnnotations{
+				Title: "Run tools with Javascript",
+			},
+			InputSchema: map[string]any{
+				"type":     "object",
+				"required": []string{"script"},
+				"properties": map[string]any{
+					"script": map[string]any{
+						"type":        "string",
+						"description": "script to execute",
+					},
+				},
+			},
+		},
+		Handler: func(ctx context.Context, request *mcp.CallToolRequest) (*mcp.CallToolResult, error) {
+			var args RunToolsWithJavascriptArgs
+			if err := json.Unmarshal(request.Params.Arguments, &args); err != nil {
+				return nil, fmt.Errorf("parsing arguments: %w", err)
+			}
+
+			output, err := c.runJavascript(ctx, args.Script)
+			if err != nil {
+				return nil, err
+			}
+
+			return &mcp.CallToolResult{
+				Content: []mcp.Content{
+					&mcp.TextContent{Text: output},
+				},
+			}, nil
+		},
+	}
+
+	return []*ToolWithHandler{jstool}, nil
+}
+
+func Wrap(toolsets []ToolSet) ToolSet {
+	return &tool{
+		toolsets: toolsets,
+	}
+}

pkg/codemode/console.go

@@ -0,0 +1,41 @@
+package codemode
+
+import (
+	"fmt"
+	"os"
+)
+
+func console() map[string]any {
+	return map[string]any{
+		"debug": consoleDebug,
+		"error": consoleError,
+		"info":  consoleInfo,
+		"log":   consoleLog,
+		"trace": consoleTrace,
+		"warn":  consoleWarn,
+	}
+}
+
+func consoleDebug(args ...any) {
+	fmt.Fprintln(os.Stdout, args...)
+}
+
+func consoleError(args ...any) {
+	fmt.Fprintln(os.Stdout, args...)
+}
+
+func consoleInfo(args ...any) {
+	fmt.Fprintln(os.Stdout, args...)
+}
+
+func consoleLog(args ...any) {
+	fmt.Fprintln(os.Stdout, args...)
+}
+
+func consoleTrace(args ...any) {
+	fmt.Fprintln(os.Stdout, args...)
+}
+
+func consoleWarn(args ...any) {
+	fmt.Fprintln(os.Stdout, args...)
+}

pkg/codemode/exec.go

@@ -0,0 +1,99 @@
+package codemode
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"slices"
+
+	"github.com/dop251/goja"
+	"github.com/modelcontextprotocol/go-sdk/mcp"
+)
+
+func (c *tool) runJavascript(ctx context.Context, script string) (string, error) {
+	vm := goja.New()
+
+	// Inject console object to the help the LLM debug its own code.
+	_ = vm.Set("console", console())
+
+	// Inject every tool as a javascript function.
+	for _, toolset := range c.toolsets {
+		allTools, err := toolset.Tools(ctx)
+		if err != nil {
+			return "", err
+		}
+
+		for _, toolWithHandler := range allTools {
+			_ = vm.Set(toolWithHandler.Tool.Name, callTool(ctx, toolWithHandler))
+		}
+	}
+
+	// Wrap the user script in an IIFE to allow top-level returns.
+	script = "(() => {\n" + script + "\n})()"
+
+	// Run the script.
+	v, err := vm.RunString(script)
+	if err != nil {
+		return fmt.Sprintf("Error running script: %s", err), nil
+	}
+
+	// Some script are fire and forget and don't return anything.
+	// In that case we return "done." to please the LLM which can't deal with empty responses.
+	result := v.Export()
+	if result == nil {
+		return "<no output>", nil
+	}
+
+	return fmt.Sprintf("%v", result), nil
+}
+
+func callTool(ctx context.Context, toolWithHandler *ToolWithHandler) func(args map[string]any) (string, error) {
+	return func(args map[string]any) (string, error) {
+		// Extract required fields from InputSchema
+		var required []string
+		if toolWithHandler.Tool.InputSchema != nil {
+			if schemaMap, ok := toolWithHandler.Tool.InputSchema.(map[string]any); ok {
+				if req, ok := schemaMap["required"].([]any); ok {
+					for _, r := range req {
+						if reqStr, ok := r.(string); ok {
+							required = append(required, reqStr)
+						}
+					}
+				} else if req, ok := schemaMap["required"].([]string); ok {
+					required = req
+				}
+			}
+		}
+
+		nonNilArgs := make(map[string]any)
+		for k, v := range args {
+			if slices.Contains(required, k) || v != nil {
+				nonNilArgs[k] = v
+			}
+		}
+
+		arguments, err := json.Marshal(nonNilArgs)
+		if err != nil {
+			return "", err
+		}
+
+		result, err := toolWithHandler.Handler(ctx, &mcp.CallToolRequest{
+			Params: &mcp.CallToolParamsRaw{
+				Name:      toolWithHandler.Tool.Name,
+				Arguments: arguments,
+			},
+		})
+		if err != nil {
+			return "", err
+		}
+
+		// Extract text from Content
+		if len(result.Content) > 0 {
+			if textContent, ok := result.Content[0].(*mcp.TextContent); ok {
+				return textContent.Text, nil
+			}
+		}
+
+		return "", nil
+	}
+}