AI: Agent Tools with bare MCP server name not expanded — agent sees zero MCP tools

[KnicKnic]

Bug

When a CustomAgentConfig specifies a bare MCP server name in its Tools list (e.g. Tools = ["github-mcp-server"]), and that MCP server is configured via SessionConfig.McpServers, the agent sees zero MCP tools after being selected via Rpc.Agent.SelectAsync(). The bare server name is not expanded to the individual MCP tool names.

Versions

• SDK: GitHub.Copilot.SDK 0.1.33-preview.0
• CLI: GitHub Copilot CLI 1.0.5
• Runtime: .NET 8.0

Expected Behavior

When an agent has Tools = ["github-mcp-server"] and the session has a McpRemoteServerConfig named "github-mcp-server", the agent should see the 18 tools exposed by that MCP server (e.g. github-mcp-server-actions_list, github-mcp-server-list_pull_requests, etc.).

Actual Behavior

The model only sees skill and report_intent (always-injected tools). Zero MCP tools are visible. The bare server name "github-mcp-server" in the agent's Tools list is not resolved to the individual MCP tool names.

Repro Output

MCP server: github-mcp-server
  Type: http
  URL:  https://api.enterprise.githubcopilot.com/mcp/readonly
Agent: mcp-agent
  Tools: [github-mcp-server]

Creating session...
Session created.

Selecting agent 'mcp-agent' via Rpc.Agent.SelectAsync...
Agent selected.

Asking model to list all its tools...

--- Model Response ---
skill, report_intent
--- End Response ---

Tools reported: 0 (ignoring skill, report_intent)

Expected MCP tools: 18
Found:   0
Missing: 18
Missing MCP tools:
  - github-mcp-server-actions_list
  - github-mcp-server-actions_get
  - github-mcp-server-get_job_logs
  - github-mcp-server-list_pull_requests
  - github-mcp-server-search_pull_requests
  - github-mcp-server-pull_request_read
  - github-mcp-server-list_issues
  - github-mcp-server-search_issues
  - github-mcp-server-issue_read
  - github-mcp-server-list_commits
  - github-mcp-server-get_commit
  - github-mcp-server-list_branches
  - github-mcp-server-search_code
  - github-mcp-server-search_repositories
  - github-mcp-server-get_file_contents
  - github-mcp-server-search_users
  - github-mcp-server-list_copilot_spaces
  - github-mcp-server-get_copilot_space

Self-Contained Repro Code

using GitHub.Copilot.SDK;

public class McpToolAgentScoped
{
    public async Task RunAsync(string cliPath)
    {
        var mcpServer = new McpRemoteServerConfig
        {
            Url = "https://api.enterprise.githubcopilot.com/mcp/readonly",
            Type = "http",
            Tools = new List<string> { "*" }
        };

        var agent = new CustomAgentConfig
        {
            Name = "mcp-agent",
            Description = "Agent with access to github-mcp-server tools",
            Prompt = "You have access to github-mcp-server tools.",
            Tools = new List<string> { "github-mcp-server" }
        };

        await using var client = new CopilotClient(new CopilotClientOptions { CliPath = cliPath });
        await client.StartAsync();

        var sessionConfig = new SessionConfig
        {
            Model = "gpt5-mini",
            McpServers = new Dictionary<string, object>
            {
                ["github-mcp-server"] = mcpServer
            },
            CustomAgents = new List<CustomAgentConfig> { agent },
            OnPermissionRequest = PermissionHandler.ApproveAll,
        };

        await using var session = await client.CreateSessionAsync(sessionConfig);

        await session.Rpc.Agent.SelectAsync("mcp-agent");

        // Ask the model what tools it sees
        var done = new TaskCompletionSource();
        string? content = null;
        using var sub = session.On(evt =>
        {
            switch (evt)
            {
                case AssistantMessageEvent msg: content = msg.Data.Content; break;
                case SessionIdleEvent: done.TrySetResult(); break;
                case SessionErrorEvent err: done.TrySetException(new Exception(err.Data.Message)); break;
            }
        });
        await session.SendAsync(new MessageOptions
        {
            Prompt = "List every tool name you have access to. Output ONLY a comma-separated list."
        });
        await done.Task;

        Console.WriteLine($"Agent Tools: [github-mcp-server]");
        Console.WriteLine($"Model sees: {content}");
        // BUG: Model sees only "skill, report_intent" — zero MCP tools
    }
}

Notes

• The MCP server itself works — when no agent scoping is used and AvailableTools = ["github-mcp-server"] is set at the session level, the tools ARE visible (though with different names than expected — see related issue).
• The CLI does not expand bare MCP server names in CustomAgentConfig.Tools to the individual <server>-<tool> names.
• VS Code handles this by doing MCP tool discovery (via tools/list JSON-RPC) and expanding bare server names before passing to the CLI. The SDK/CLI should handle this natively.