Add support for read-only flag on GitHub tool configuration

docs/src/content/docs/reference/tools.md

@@ -46,8 +46,23 @@ tools:
     allowed: [create_issue, update_issue, add_issue_comment]  # Optional: specific permissions
     version: "latest"                          # Optional: MCP server version
     args: ["--verbose", "--debug"]            # Optional: additional command-line arguments
+    read-only: true                           # Optional: restrict to read-only operations
 ```
 
+### GitHub Read-Only Mode
+
+The `read-only` flag restricts the GitHub MCP server to read-only operations, preventing any modifications to repositories, issues, pull requests, etc.
+
+```yaml
+tools:
+  github:
+    read-only: true
+```
+
+When `read-only: true` is specified, the GitHub MCP server runs with the `GITHUB_READ_ONLY` environment variable set, which enables read-only mode at the server level.
+
+**Default behavior**: When the GitHub tool is specified without any configuration (just `github:` with no properties), the default behavior provides read-only access with all read-only tools available.
+
 ### GitHub Args Configuration
 
 The `args` field allows you to pass additional command-line arguments to the GitHub MCP server:

pkg/parser/mcp.go

@@ -264,6 +264,14 @@ func processBuiltinMCPTool(toolName string, toolValue any, serverFilter string)
 
 		// Check for custom GitHub configuration
 		if toolConfig, ok := toolValue.(map[string]any); ok {
+			// Check for read-only mode
+			if readOnly, hasReadOnly := toolConfig["read-only"]; hasReadOnly {
+				if readOnlyBool, ok := readOnly.(bool); ok && readOnlyBool {
+					// When read-only is true, inline GITHUB_READ_ONLY=1 in docker args
+					config.Args = append(config.Args[:5], append([]string{"-e", "GITHUB_READ_ONLY=1"}, config.Args[5:]...)...)
+				}
+			}
+
 			if allowed, hasAllowed := toolConfig["allowed"]; hasAllowed {
 				if allowedSlice, ok := allowed.([]any); ok {
 					for _, item := range allowedSlice {

pkg/parser/mcp_test.go

@@ -74,6 +74,80 @@ func TestExtractMCPConfigurations(t *testing.T) {
 		expected     []MCPServerConfig
 		expectError  bool
 	}{
+		{
+			name: "GitHub tool with read-only true",
+			frontmatter: map[string]any{
+				"tools": map[string]any{
+					"github": map[string]any{
+						"read-only": true,
+					},
+				},
+			},
+			expected: []MCPServerConfig{
+				{
+					Name:    "github",
+					Type:    "docker",
+					Command: "docker",
+					Args: []string{
+						"run", "-i", "--rm", "-e", "GITHUB_PERSONAL_ACCESS_TOKEN",
+						"-e", "GITHUB_READ_ONLY=1",
+						"ghcr.io/github/github-mcp-server:sha-09deac4",
+					},
+					Env: map[string]string{
+						"GITHUB_PERSONAL_ACCESS_TOKEN": "${GITHUB_TOKEN_REQUIRED}",
+					},
+					Allowed: []string{},
+				},
+			},
+		},
+		{
+			name: "GitHub tool with read-only false",
+			frontmatter: map[string]any{
+				"tools": map[string]any{
+					"github": map[string]any{
+						"read-only": false,
+					},
+				},
+			},
+			expected: []MCPServerConfig{
+				{
+					Name:    "github",
+					Type:    "docker",
+					Command: "docker",
+					Args: []string{
+						"run", "-i", "--rm", "-e", "GITHUB_PERSONAL_ACCESS_TOKEN",
+						"ghcr.io/github/github-mcp-server:sha-09deac4",
+					},
+					Env: map[string]string{
+						"GITHUB_PERSONAL_ACCESS_TOKEN": "${GITHUB_TOKEN_REQUIRED}",
+					},
+					Allowed: []string{},
+				},
+			},
+		},
+		{
+			name: "GitHub tool without read-only (default behavior)",
+			frontmatter: map[string]any{
+				"tools": map[string]any{
+					"github": map[string]any{},
+				},
+			},
+			expected: []MCPServerConfig{
+				{
+					Name:    "github",
+					Type:    "docker",
+					Command: "docker",
+					Args: []string{
+						"run", "-i", "--rm", "-e", "GITHUB_PERSONAL_ACCESS_TOKEN",
+						"ghcr.io/github/github-mcp-server:sha-09deac4",
+					},
+					Env: map[string]string{
+						"GITHUB_PERSONAL_ACCESS_TOKEN": "${GITHUB_TOKEN_REQUIRED}",
+					},
+					Allowed: []string{},
+				},
+			},
+		},
 		{
 			name: "New format: Custom MCP server with direct fields",
 			frontmatter: map[string]any{

pkg/parser/schemas/main_workflow_schema.json

@@ -984,6 +984,10 @@
         "github": {
           "description": "GitHub API tools for repository operations (issues, pull requests, content management)",
           "oneOf": [
+            {
+              "type": "null",
+              "description": "Empty GitHub tool configuration (enables all read-only GitHub API functions)"
+            },
             {
               "type": "string",
               "description": "Simple GitHub tool configuration (enables all GitHub API functions)"
@@ -1009,6 +1013,10 @@
                   "items": {
                     "type": "string"
                   }
+                },
+                "read-only": {
+                  "type": "boolean",
+                  "description": "Enable read-only mode to restrict GitHub MCP server to read-only operations only"
                 }
               },
               "additionalProperties": false

pkg/workflow/claude_engine.go

@@ -627,6 +627,7 @@ func (e *ClaudeEngine) RenderMCPConfig(yaml *strings.Builder, tools map[string]a
 func (e *ClaudeEngine) renderGitHubClaudeMCPConfig(yaml *strings.Builder, githubTool any, isLast bool, workflowData *WorkflowData) {
 	githubDockerImageVersion := getGitHubDockerImageVersion(githubTool)
 	customArgs := getGitHubCustomArgs(githubTool)
+	readOnly := getGitHubReadOnly(githubTool)
 
 	yaml.WriteString("              \"github\": {\n")
 
@@ -638,6 +639,10 @@ func (e *ClaudeEngine) renderGitHubClaudeMCPConfig(yaml *strings.Builder, github
 	yaml.WriteString("                  \"--rm\",\n")
 	yaml.WriteString("                  \"-e\",\n")
 	yaml.WriteString("                  \"GITHUB_PERSONAL_ACCESS_TOKEN\",\n")
+	if readOnly {
+		yaml.WriteString("                  \"-e\",\n")
+		yaml.WriteString("                  \"GITHUB_READ_ONLY=1\",\n")
+	}
 	yaml.WriteString("                  \"ghcr.io/github/github-mcp-server:" + githubDockerImageVersion + "\"")
 
 	// Append custom args if present

pkg/workflow/codex_engine.go

@@ -478,6 +478,7 @@ func (e *CodexEngine) extractCodexTokenUsage(line string) int {
 func (e *CodexEngine) renderGitHubCodexMCPConfig(yaml *strings.Builder, githubTool any, workflowData *WorkflowData) {
 	githubDockerImageVersion := getGitHubDockerImageVersion(githubTool)
 	customArgs := getGitHubCustomArgs(githubTool)
+	readOnly := getGitHubReadOnly(githubTool)
 
 	yaml.WriteString("          \n")
 	yaml.WriteString("          [mcp_servers.github]\n")
@@ -503,6 +504,10 @@ func (e *CodexEngine) renderGitHubCodexMCPConfig(yaml *strings.Builder, githubTo
 	yaml.WriteString("            \"--rm\",\n")
 	yaml.WriteString("            \"-e\",\n")
 	yaml.WriteString("            \"GITHUB_PERSONAL_ACCESS_TOKEN\",\n")
+	if readOnly {
+		yaml.WriteString("            \"-e\",\n")
+		yaml.WriteString("            \"GITHUB_READ_ONLY=1\",\n")
+	}
 	yaml.WriteString("            \"ghcr.io/github/github-mcp-server:" + githubDockerImageVersion + "\"")
 
 	// Append custom args if present

pkg/workflow/copilot_engine.go

@@ -255,6 +255,7 @@ func (e *CopilotEngine) RenderMCPConfig(yaml *strings.Builder, tools map[string]
 func (e *CopilotEngine) renderGitHubCopilotMCPConfig(yaml *strings.Builder, githubTool any, isLast bool, workflowData *WorkflowData) {
 	githubDockerImageVersion := getGitHubDockerImageVersion(githubTool)
 	customArgs := getGitHubCustomArgs(githubTool)
+	readOnly := getGitHubReadOnly(githubTool)
 
 	yaml.WriteString("              \"github\": {\n")
 	yaml.WriteString("                \"type\": \"local\",\n")
@@ -267,6 +268,10 @@ func (e *CopilotEngine) renderGitHubCopilotMCPConfig(yaml *strings.Builder, gith
 	yaml.WriteString("                  \"--rm\",\n")
 	yaml.WriteString("                  \"-e\",\n")
 	yaml.WriteString("                  \"GITHUB_PERSONAL_ACCESS_TOKEN=${{ secrets.GITHUB_TOKEN }}\",\n")
+	if readOnly {
+		yaml.WriteString("                  \"-e\",\n")
+		yaml.WriteString("                  \"GITHUB_READ_ONLY=1\",\n")
+	}
 	yaml.WriteString("                  \"ghcr.io/github/github-mcp-server:" + githubDockerImageVersion + "\"")
 
 	// Append custom args if present

pkg/workflow/custom_engine.go

@@ -183,6 +183,7 @@ func (e *CustomEngine) RenderMCPConfig(yaml *strings.Builder, tools map[string]a
 func (e *CustomEngine) renderGitHubMCPConfig(yaml *strings.Builder, githubTool any, isLast bool) {
 	githubDockerImageVersion := getGitHubDockerImageVersion(githubTool)
 	customArgs := getGitHubCustomArgs(githubTool)
+	readOnly := getGitHubReadOnly(githubTool)
 
 	yaml.WriteString("              \"github\": {\n")
 
@@ -194,6 +195,10 @@ func (e *CustomEngine) renderGitHubMCPConfig(yaml *strings.Builder, githubTool a
 	yaml.WriteString("                  \"--rm\",\n")
 	yaml.WriteString("                  \"-e\",\n")
 	yaml.WriteString("                  \"GITHUB_PERSONAL_ACCESS_TOKEN\",\n")
+	if readOnly {
+		yaml.WriteString("                  \"-e\",\n")
+		yaml.WriteString("                  \"GITHUB_READ_ONLY=1\",\n")
+	}
 	yaml.WriteString("                  \"ghcr.io/github/github-mcp-server:" + githubDockerImageVersion + "\"")
 
 	// Append custom args if present

pkg/workflow/github_readonly_test.go

@@ -0,0 +1,59 @@
+package workflow
+
+import "testing"
+
+func TestGetGitHubReadOnly(t *testing.T) {
+	tests := []struct {
+		name       string
+		githubTool any
+		expected   bool
+	}{
+		{
+			name: "read-only true",
+			githubTool: map[string]any{
+				"read-only": true,
+			},
+			expected: true,
+		},
+		{
+			name: "read-only false",
+			githubTool: map[string]any{
+				"read-only": false,
+			},
+			expected: false,
+		},
+		{
+			name:       "no read-only field",
+			githubTool: map[string]any{},
+			expected:   false,
+		},
+		{
+			name: "read-only with other fields",
+			githubTool: map[string]any{
+				"read-only": true,
+				"version":   "latest",
+				"args":      []string{"--verbose"},
+			},
+			expected: true,
+		},
+		{
+			name:       "nil tool",
+			githubTool: nil,
+			expected:   false,
+		},
+		{
+			name:       "string tool (not map)",
+			githubTool: "github",
+			expected:   false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := getGitHubReadOnly(tt.githubTool)
+			if result != tt.expected {
+				t.Errorf("getGitHubReadOnly() = %v, want %v", result, tt.expected)
+			}
+		})
+	}
+}