feat(resources): return issue resource as single markdown document

Consolidate the issue resource into a single ResourceContents item
containing the issue body, frontmatter metadata, and all comments
separated by --- delimiters.

- Return one markdown file instead of multiple content items
- Use .md extension in URI template for editor preview support
- Convert HTML <img> tags to markdown image syntax
- Keep original image URLs (private images won't render in preview)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: SamMorrowDrums

pkg/github/issue_resource.go

@@ -0,0 +1,279 @@
+package github
+
+import (
+	"context"
+	"fmt"
+	"regexp"
+	"strconv"
+	"strings"
+
+	"github.com/github/github-mcp-server/pkg/inventory"
+	"github.com/github/github-mcp-server/pkg/octicons"
+	"github.com/github/github-mcp-server/pkg/sanitize"
+	"github.com/github/github-mcp-server/pkg/translations"
+	"github.com/google/go-github/v82/github"
+	"github.com/modelcontextprotocol/go-sdk/mcp"
+	"github.com/yosida95/uritemplate/v3"
+)
+
+var issueResourceURITemplate = uritemplate.MustNew("issue://{owner}/{repo}/issues/{issueNumber}.md")
+
+// htmlImagePattern matches HTML img tags: <img ... src="url" ... />
+var htmlImagePattern = regexp.MustCompile(`<img\b([^>]*)\bsrc=["']([^"']+)["']([^>]*)/??>`)
+
+// htmlAltPattern extracts the alt attribute value from an img tag fragment.
+var htmlAltPattern = regexp.MustCompile(`\balt=["']([^"']*)["']`)
+
+// GetIssueResourceContent defines the resource template for reading issue content.
+func GetIssueResourceContent(t translations.TranslationHelperFunc) inventory.ServerResourceTemplate {
+	return inventory.NewServerResourceTemplate(
+		ToolsetMetadataIssues,
+		mcp.ResourceTemplate{
+			Name:        "issue_content",
+			URITemplate: issueResourceURITemplate.Raw(),
+			Description: t("RESOURCE_ISSUE_CONTENT_DESCRIPTION", "Issue content with comments and embedded images as a single markdown document"),
+			Icons:       octicons.Icons("issue-opened"),
+		},
+		issueResourceHandlerFunc(),
+	)
+}
+
+func issueResourceHandlerFunc() inventory.ResourceHandlerFunc {
+	return func(_ any) mcp.ResourceHandler {
+		return IssueResourceHandler()
+	}
+}
+
+// IssueResourceHandler returns a handler for issue resource requests.
+func IssueResourceHandler() mcp.ResourceHandler {
+	return func(ctx context.Context, request *mcp.ReadResourceRequest) (*mcp.ReadResourceResult, error) {
+		deps := MustDepsFromContext(ctx)
+
+		uriValues := issueResourceURITemplate.Match(request.Params.URI)
+		if uriValues == nil {
+			return nil, fmt.Errorf("failed to match URI: %s", request.Params.URI)
+		}
+
+		owner := uriValues.Get("owner").String()
+		repo := uriValues.Get("repo").String()
+		issueNumberStr := uriValues.Get("issueNumber").String()
+
+		if owner == "" {
+			return nil, fmt.Errorf("owner is required")
+		}
+		if repo == "" {
+			return nil, fmt.Errorf("repo is required")
+		}
+		if issueNumberStr == "" {
+			return nil, fmt.Errorf("issueNumber is required")
+		}
+
+		issueNumber, err := strconv.Atoi(issueNumberStr)
+		if err != nil {
+			return nil, fmt.Errorf("invalid issue number: %w", err)
+		}
+
+		client, err := deps.GetClient(ctx)
+		if err != nil {
+			return nil, fmt.Errorf("failed to get GitHub client: %w", err)
+		}
+
+		// Fetch the issue
+		issue, _, err := client.Issues.Get(ctx, owner, repo, issueNumber)
+		if err != nil {
+			return nil, fmt.Errorf("failed to get issue: %w", err)
+		}
+
+		// Build unified markdown document
+		var doc strings.Builder
+
+		// Issue body with frontmatter
+		body := sanitize.Sanitize(issue.GetBody())
+		frontmatter := buildIssueFrontmatter(issue)
+		doc.WriteString(frontmatter)
+		doc.WriteString(convertHTMLImagesToMarkdown(body))
+
+		// Fetch all comments
+		comments, err := fetchAllIssueComments(ctx, client, owner, repo, issueNumber)
+		if err != nil {
+			return nil, fmt.Errorf("failed to get issue comments: %w", err)
+		}
+
+		for _, comment := range comments {
+			doc.WriteString("\n\n---\n\n")
+			commentBody := sanitize.Sanitize(comment.GetBody())
+			commentFrontmatter := buildCommentFrontmatter(comment)
+			doc.WriteString(commentFrontmatter)
+			doc.WriteString(convertHTMLImagesToMarkdown(commentBody))
+		}
+
+		resourceURI := fmt.Sprintf("issue://%s/%s/issues/%d.md", owner, repo, issueNumber)
+		contents := []*mcp.ResourceContents{
+			{
+				URI:      resourceURI,
+				MIMEType: "text/markdown",
+				Text:     doc.String(),
+			},
+		}
+
+		return &mcp.ReadResourceResult{Contents: contents}, nil
+	}
+}
+
+func buildIssueFrontmatter(issue *github.Issue) string {
+	var b strings.Builder
+	b.WriteString("---\n")
+	b.WriteString(fmt.Sprintf("title: %q\n", sanitize.Sanitize(issue.GetTitle())))
+	b.WriteString(fmt.Sprintf("state: %s\n", issue.GetState()))
+	if user := issue.GetUser(); user != nil {
+		b.WriteString(fmt.Sprintf("author: %s\n", user.GetLogin()))
+	}
+	if issue.CreatedAt != nil {
+		b.WriteString(fmt.Sprintf("created_at: %s\n", issue.CreatedAt.Format("2006-01-02T15:04:05Z")))
+	}
+	if len(issue.Labels) > 0 {
+		b.WriteString("labels:\n")
+		for _, label := range issue.Labels {
+			if label != nil {
+				b.WriteString(fmt.Sprintf("  - %s\n", label.GetName()))
+			}
+		}
+	}
+	if issue.GetMilestone() != nil {
+		b.WriteString(fmt.Sprintf("milestone: %s\n", issue.GetMilestone().GetTitle()))
+	}
+	b.WriteString("---\n\n")
+	return b.String()
+}
+
+func buildCommentFrontmatter(comment *github.IssueComment) string {
+	var b strings.Builder
+	b.WriteString("---\n")
+	if user := comment.GetUser(); user != nil {
+		b.WriteString(fmt.Sprintf("author: %s\n", user.GetLogin()))
+	}
+	b.WriteString(fmt.Sprintf("author_association: %s\n", comment.GetAuthorAssociation()))
+	if comment.CreatedAt != nil {
+		b.WriteString(fmt.Sprintf("created_at: %s\n", comment.CreatedAt.Format("2006-01-02T15:04:05Z")))
+	}
+	if comment.UpdatedAt != nil {
+		b.WriteString(fmt.Sprintf("updated_at: %s\n", comment.UpdatedAt.Format("2006-01-02T15:04:05Z")))
+	}
+	b.WriteString("---\n\n")
+	return b.String()
+}
+
+// convertHTMLImagesToMarkdown converts HTML <img> tags to markdown image syntax.
+func convertHTMLImagesToMarkdown(body string) string {
+	return htmlImagePattern.ReplaceAllStringFunc(body, func(match string) string {
+		submatches := htmlImagePattern.FindStringSubmatch(match)
+		if len(submatches) < 3 {
+			return match
+		}
+		imageURL := submatches[2]
+		alt := ""
+		attrs := submatches[1] + submatches[3]
+		if altMatch := htmlAltPattern.FindStringSubmatch(attrs); len(altMatch) >= 2 {
+			alt = altMatch[1]
+		}
+		return fmt.Sprintf("![%s](%s)", alt, imageURL)
+	})
+}
+
+func fetchAllIssueComments(ctx context.Context, client *github.Client, owner, repo string, issueNumber int) ([]*github.IssueComment, error) {
+	var allComments []*github.IssueComment
+	opts := &github.IssueListCommentsOptions{
+		ListOptions: github.ListOptions{PerPage: 100},
+	}
+	for {
+		comments, resp, err := client.Issues.ListComments(ctx, owner, repo, issueNumber, opts)
+		if err != nil {
+			return nil, err
+		}
+		_ = resp.Body.Close()
+		allComments = append(allComments, comments...)
+		if resp.NextPage == 0 {
+			break
+		}
+		opts.Page = resp.NextPage
+	}
+	return allComments, nil
+}
+
+// IssueResourceCompletionHandler returns a completion handler for issue resource URI templates.
+func IssueResourceCompletionHandler(getClient GetClientFn) func(ctx context.Context, req *mcp.CompleteRequest) (*mcp.CompleteResult, error) {
+	return func(ctx context.Context, req *mcp.CompleteRequest) (*mcp.CompleteResult, error) {
+		if req.Params.Ref.Type != "ref/resource" {
+			return nil, nil
+		}
+
+		argName := req.Params.Argument.Name
+		argValue := req.Params.Argument.Value
+		var resolved map[string]string
+		if req.Params.Context != nil && req.Params.Context.Arguments != nil {
+			resolved = req.Params.Context.Arguments
+		} else {
+			resolved = map[string]string{}
+		}
+
+		client, err := getClient(ctx)
+		if err != nil {
+			return nil, err
+		}
+
+		// Reuse owner and repo resolvers from repository resource completions
+		resolvers := map[string]CompleteHandler{
+			"owner":       completeOwner,
+			"repo":        completeRepo,
+			"issueNumber": completeIssueNumber,
+		}
+
+		resolver, ok := resolvers[argName]
+		if !ok {
+			return nil, fmt.Errorf("no resolver for argument: %s", argName)
+		}
+
+		values, err := resolver(ctx, client, resolved, argValue)
+		if err != nil {
+			return nil, err
+		}
+		if len(values) > 100 {
+			values = values[:100]
+		}
+
+		return &mcp.CompleteResult{
+			Completion: mcp.CompletionResultDetails{
+				Values:  values,
+				Total:   len(values),
+				HasMore: false,
+			},
+		}, nil
+	}
+}
+
+func completeIssueNumber(ctx context.Context, client *github.Client, resolved map[string]string, argValue string) ([]string, error) {
+	owner := resolved["owner"]
+	repo := resolved["repo"]
+	if owner == "" || repo == "" {
+		return nil, fmt.Errorf("owner or repo not specified")
+	}
+
+	issues, _, err := client.Search.Issues(ctx, fmt.Sprintf("repo:%s/%s is:issue", owner, repo), &github.SearchOptions{
+		ListOptions: github.ListOptions{PerPage: 100},
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	var values []string
+	for _, issue := range issues.Issues {
+		num := fmt.Sprintf("%d", issue.GetNumber())
+		if argValue == "" || strings.HasPrefix(num, argValue) {
+			values = append(values, num)
+		}
+	}
+	if len(values) > 100 {
+		values = values[:100]
+	}
+	return values, nil
+}