Add list_issue_fields tool

README.md

@@ -874,6 +874,12 @@ The following sets of tools are available:
   - `title`: Issue title (string, optional)
   - `type`: Type of this issue. Only use if the repository has issue types configured. Use list_issue_types tool to get valid type values for the organization. If the repository doesn't support issue types, omit this parameter. (string, optional)
 
+- **list_issue_fields** - List issue fields
+  - **Required OAuth Scopes**: `repo`, `read:org`
+  - **Accepted OAuth Scopes**: `admin:org`, `read:org`, `repo`, `write:org`
+  - `owner`: The account owner of the repository or organization. The name is not case sensitive. (string, required)
+  - `repo`: The name of the repository. When provided, returns fields for this specific repository (inherited from its organization). When omitted, returns org-level fields directly. (string, optional)
+
 - **list_issue_types** - List available issue types
   - **Required OAuth Scopes**: `read:org`
   - **Accepted OAuth Scopes**: `admin:org`, `read:org`, `write:org`

pkg/github/__toolsnaps__/list_issue_fields.snap

@@ -0,0 +1,24 @@
+{
+  "annotations": {
+    "readOnlyHint": true,
+    "title": "List issue fields"
+  },
+  "description": "List issue fields for a repository or organization. Returns field definitions including name, type (text, number, date, single_select), and for single_select fields the list of valid option names. When repo is omitted, returns org-level fields directly.",
+  "inputSchema": {
+    "properties": {
+      "owner": {
+        "description": "The account owner of the repository or organization. The name is not case sensitive.",
+        "type": "string"
+      },
+      "repo": {
+        "description": "The name of the repository. When provided, returns fields for this specific repository (inherited from its organization). When omitted, returns org-level fields directly.",
+        "type": "string"
+      }
+    },
+    "required": [
+      "owner"
+    ],
+    "type": "object"
+  },
+  "name": "list_issue_fields"
+}

pkg/github/issue_fields.go

@@ -0,0 +1,223 @@
+package github
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+
+	ghcontext "github.com/github/github-mcp-server/pkg/context"
+	ghErrors "github.com/github/github-mcp-server/pkg/errors"
+	"github.com/github/github-mcp-server/pkg/inventory"
+	"github.com/github/github-mcp-server/pkg/scopes"
+	"github.com/github/github-mcp-server/pkg/translations"
+	"github.com/github/github-mcp-server/pkg/utils"
+	"github.com/google/jsonschema-go/jsonschema"
+	"github.com/modelcontextprotocol/go-sdk/mcp"
+	"github.com/shurcooL/githubv4"
+)
+
+// IssueField represents a repository issue field definition.
+type IssueField struct {
+	ID          string                         `json:"id"`
+	Name        string                         `json:"name"`
+	Description string                         `json:"description,omitempty"`
+	DataType    string                         `json:"data_type"`
+	Visibility  string                         `json:"visibility"`
+	Options     []IssueSingleSelectFieldOption `json:"options,omitempty"`
+}
+
+// IssueSingleSelectFieldOption represents an option for a single_select issue field.
+type IssueSingleSelectFieldOption struct {
+	ID          string `json:"id"`
+	Name        string `json:"name"`
+	Description string `json:"description,omitempty"`
+	Color       string `json:"color"`
+	Priority    *int   `json:"priority,omitempty"`
+}
+
+// issueFieldNode is the GraphQL fragment for a single issue field in the IssueFields union.
+// Only the fragment matching __typename is populated; read from the matching fragment.
+type issueFieldNode struct {
+	TypeName       githubv4.String `graphql:"__typename"`
+	IssueFieldText struct {
+		ID          githubv4.ID
+		Name        githubv4.String
+		Description githubv4.String
+		DataType    githubv4.String
+		Visibility  githubv4.String
+	} `graphql:"... on IssueFieldText"`
+	IssueFieldNumber struct {
+		ID          githubv4.ID
+		Name        githubv4.String
+		Description githubv4.String
+		DataType    githubv4.String
+		Visibility  githubv4.String
+	} `graphql:"... on IssueFieldNumber"`
+	IssueFieldDate struct {
+		ID          githubv4.ID
+		Name        githubv4.String
+		Description githubv4.String
+		DataType    githubv4.String
+		Visibility  githubv4.String
+	} `graphql:"... on IssueFieldDate"`
+	IssueFieldSingleSelect struct {
+		ID          githubv4.ID
+		Name        githubv4.String
+		Description githubv4.String
+		DataType    githubv4.String
+		Visibility  githubv4.String
+		Options     []struct {
+			ID          githubv4.ID
+			Name        githubv4.String
+			Description githubv4.String
+			Color       githubv4.String
+			Priority    *int
+		}
+	} `graphql:"... on IssueFieldSingleSelect"`
+}
+
+// issueFieldsRepoQuery is the GraphQL query for listing issue fields on a repository.
+type issueFieldsRepoQuery struct {
+	Repository struct {
+		IssueFields struct {
+			Nodes []issueFieldNode
+		} `graphql:"issueFields(first: 100)"`
+	} `graphql:"repository(owner: $owner, name: $name)"`
+}
+
+// issueFieldsOrgQuery is the GraphQL query for listing issue fields on an organization.
+type issueFieldsOrgQuery struct {
+	Organization struct {
+		IssueFields struct {
+			Nodes []issueFieldNode
+		} `graphql:"issueFields(first: 100)"`
+	} `graphql:"organization(login: $login)"`
+}
+
+// ListIssueFields creates a tool to list issue field definitions for a repository or organization.
+func ListIssueFields(t translations.TranslationHelperFunc) inventory.ServerTool {
+	return NewTool(
+		ToolsetMetadataIssues,
+		mcp.Tool{
+			Name:        "list_issue_fields",
+			Description: t("TOOL_LIST_ISSUE_FIELDS_DESCRIPTION", "List issue fields for a repository or organization. Returns field definitions including name, type (text, number, date, single_select), and for single_select fields the list of valid option names. When repo is omitted, returns org-level fields directly."),
+			Annotations: &mcp.ToolAnnotations{
+				Title:        t("TOOL_LIST_ISSUE_FIELDS_USER_TITLE", "List issue fields"),
+				ReadOnlyHint: true,
+			},
+			InputSchema: &jsonschema.Schema{
+				Type: "object",
+				Properties: map[string]*jsonschema.Schema{
+					"owner": {
+						Type:        "string",
+						Description: "The account owner of the repository or organization. The name is not case sensitive.",
+					},
+					"repo": {
+						Type:        "string",
+						Description: "The name of the repository. When provided, returns fields for this specific repository (inherited from its organization). When omitted, returns org-level fields directly.",
+					},
+				},
+				Required: []string{"owner"},
+			},
+		},
+		[]scopes.Scope{scopes.Repo, scopes.ReadOrg},
+		func(ctx context.Context, deps ToolDependencies, _ *mcp.CallToolRequest, args map[string]any) (*mcp.CallToolResult, any, error) {
+			owner, err := RequiredParam[string](args, "owner")
+			if err != nil {
+				return utils.NewToolResultError(err.Error()), nil, nil
+			}
+			repo, err := OptionalParam[string](args, "repo")
+			if err != nil {
+				return utils.NewToolResultError(err.Error()), nil, nil
+			}
+
+			gqlClient, err := deps.GetGQLClient(ctx)
+			if err != nil {
+				return utils.NewToolResultErrorFromErr("failed to get GitHub GraphQL client", err), nil, nil
+			}
+
+			ctxWithFeatures := ghcontext.WithGraphQLFeatures(ctx, "issue_fields")
+			var nodes []issueFieldNode
+			if repo != "" {
+				var query issueFieldsRepoQuery
+				vars := map[string]any{
+					"owner": githubv4.String(owner),
+					"name":  githubv4.String(repo),
+				}
+				if err := gqlClient.Query(ctxWithFeatures, &query, vars); err != nil {
+					return ghErrors.NewGitHubGraphQLErrorResponse(ctx, "failed to list issue fields", err), nil, nil
+				}
+				nodes = query.Repository.IssueFields.Nodes
+			} else {
+				var query issueFieldsOrgQuery
+				vars := map[string]any{
+					"login": githubv4.String(owner),
+				}
+				if err := gqlClient.Query(ctxWithFeatures, &query, vars); err != nil {
+					return ghErrors.NewGitHubGraphQLErrorResponse(ctx, "failed to list issue fields", err), nil, nil
+				}
+				nodes = query.Organization.IssueFields.Nodes
+			}
+
+			fields := make([]IssueField, 0, len(nodes))
+			for _, node := range nodes {
+				var f IssueField
+				// Read from the fragment matching __typename; the other fragments are zero-valued.
+				switch string(node.TypeName) {
+				case "IssueFieldSingleSelect":
+					opts := make([]IssueSingleSelectFieldOption, 0, len(node.IssueFieldSingleSelect.Options))
+					for _, o := range node.IssueFieldSingleSelect.Options {
+						opts = append(opts, IssueSingleSelectFieldOption{
+							ID:          fmt.Sprintf("%v", o.ID),
+							Name:        string(o.Name),
+							Description: string(o.Description),
+							Color:       string(o.Color),
+							Priority:    o.Priority,
+						})
+					}
+					f = IssueField{
+						ID:          fmt.Sprintf("%v", node.IssueFieldSingleSelect.ID),
+						Name:        string(node.IssueFieldSingleSelect.Name),
+						Description: string(node.IssueFieldSingleSelect.Description),
+						DataType:    string(node.IssueFieldSingleSelect.DataType),
+						Visibility:  string(node.IssueFieldSingleSelect.Visibility),
+						Options:     opts,
+					}
+				case "IssueFieldText":
+					f = IssueField{
+						ID:          fmt.Sprintf("%v", node.IssueFieldText.ID),
+						Name:        string(node.IssueFieldText.Name),
+						Description: string(node.IssueFieldText.Description),
+						DataType:    string(node.IssueFieldText.DataType),
+						Visibility:  string(node.IssueFieldText.Visibility),
+					}
+				case "IssueFieldNumber":
+					f = IssueField{
+						ID:          fmt.Sprintf("%v", node.IssueFieldNumber.ID),
+						Name:        string(node.IssueFieldNumber.Name),
+						Description: string(node.IssueFieldNumber.Description),
+						DataType:    string(node.IssueFieldNumber.DataType),
+						Visibility:  string(node.IssueFieldNumber.Visibility),
+					}
+				case "IssueFieldDate":
+					f = IssueField{
+						ID:          fmt.Sprintf("%v", node.IssueFieldDate.ID),
+						Name:        string(node.IssueFieldDate.Name),
+						Description: string(node.IssueFieldDate.Description),
+						DataType:    string(node.IssueFieldDate.DataType),
+						Visibility:  string(node.IssueFieldDate.Visibility),
+					}
+				default:
+					continue
+				}
+				fields = append(fields, f)
+			}
+
+			r, err := json.Marshal(fields)
+			if err != nil {
+				return utils.NewToolResultErrorFromErr("failed to marshal issue fields", err), nil, nil
+			}
+
+			return utils.NewToolResultText(string(r)), nil, nil
+		})
+}