fix: Correctly structure tool responses

Refactored list_issues, update_issue, add_issue_comment, and get_issue
tools to return their responses in the correct MCP `content` structure following the spec https://github.com/modelcontextprotocol/specification/blob/main/schema/schema.json#L80

src/github/index.ts

@@ -978,21 +978,21 @@ server.setRequestHandler(CallToolRequestSchema, async (request) => {
         const args = ListIssuesOptionsSchema.parse(request.params.arguments);
         const { owner, repo, ...options } = args;
         const issues = await listIssues(owner, repo, options);
-        return { toolResult: issues };
+        return { content: [{ type: "text", text: JSON.stringify(issues, null, 2) }] };
       }
 
       case "update_issue": {
         const args = UpdateIssueOptionsSchema.parse(request.params.arguments);
         const { owner, repo, issue_number, ...options } = args;
         const issue = await updateIssue(owner, repo, issue_number, options);
-        return { toolResult: issue };
+        return { content: [{ type: "text", text: JSON.stringify(issue, null, 2) }] };
       }
 
       case "add_issue_comment": {
         const args = IssueCommentSchema.parse(request.params.arguments);
         const { owner, repo, issue_number, body } = args;
         const comment = await addIssueComment(owner, repo, issue_number, body);
-        return { toolResult: comment };
+        return { content: [{ type: "text", text: JSON.stringify(comment, null, 2) }] };
       }
 
       case "list_commits": {
@@ -1008,7 +1008,7 @@ server.setRequestHandler(CallToolRequestSchema, async (request) => {
           issue_number: z.number()
         }).parse(request.params.arguments);
         const issue = await getIssue(args.owner, args.repo, args.issue_number);
-        return { toolResult: issue };
+        return { content: [{ type: "text", text: JSON.stringify(issue, null, 2) }] };
       }
 
       default: