MCP-Client fuer HTTP-Server: externe Werkzeuge durch dieselben Pruefstellen (#197)

- Core/Mcp/McpClient: Streamable HTTP (MCP 2025-06-18) - initialize, tools/list with paging, tools/call; answers as JSON or event stream; session kept and opened again when the server forgets it; answers capped at 4 MB. - McpServerTool: one server is one tool (mcp_<id>); its remote tools are the operations, so rights, preflight, staging, lead approvals, votes, audit and budget apply. On approval by default unless the human trusts an operation; reads foreign content; the server's descriptions are cut short and marked. - McpConnections: registers, refreshes every 15 minutes, follows changes. - InstanceConfig.mcpServers with protected headers; /api/mcp-servers; settings card "External MCP servers"; tool catalog includes the servers. - stdio servers are not part of this (sandbox runner, separate step). Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-01 18:15:44 +02:00
parent 44844a41a0
commit caf4323012
19 changed files with 1089 additions and 5 deletions
@@ -115,6 +115,50 @@ internal static class McpEndpoints
                ? Results.Ok(new OutcomeDto(true, "Revoked."))
                : Results.NotFound(new OutcomeDto(false, $"No active trigger '{id}'.")));

+        // #197: External MCP servers — the human adds them, the agents use them as tools.
+        var servers = app.MapGroup("/api/mcp-servers");
+
+        servers.MapGet("/", (AppHost host) => Results.Ok(host.Instance.McpServers.Select(s => ServerDto(host, s)).ToList()));
+
+        servers.MapPost("/", async (AppHost host, McpServerInputDto input, CancellationToken ct) =>
+        {
+            var id = (input.Id ?? "").Trim().ToLowerInvariant();
+            if (!Core.Mcp.McpConnections.IdPattern().IsMatch(id))
+                return Results.BadRequest(new OutcomeDto(false, "An id is 1–31 lower-case letters, digits, '-' or '_'."));
+            if (host.Instance.McpServers.Any(s => string.Equals(s.Id, id, StringComparison.OrdinalIgnoreCase)))
+                return Results.BadRequest(new OutcomeDto(false, $"There is already a server '{id}'."));
+            var server = new Core.Mcp.McpServerConfig { Id = id };
+            if (Apply(server, input) is { } problem)
+                return Results.BadRequest(new OutcomeDto(false, problem));
+            host.Instance.McpServers.Add(server);
+            return await SaveAndSyncAsync(host, $"MCP server '{server.Name}' added as tool {Core.Mcp.McpServerTool.NameFor(id)}.", ct);
+        });
+
+        servers.MapPut("/{id}", async (AppHost host, string id, McpServerInputDto input, CancellationToken ct) =>
+        {
+            if (host.Instance.McpServers.FirstOrDefault(s => string.Equals(s.Id, id, StringComparison.OrdinalIgnoreCase)) is not { } server)
+                return Results.NotFound(new OutcomeDto(false, $"No server '{id}'."));
+            if (Apply(server, input) is { } problem)
+                return Results.BadRequest(new OutcomeDto(false, problem));
+            return await SaveAndSyncAsync(host, $"MCP server '{server.Name}' saved.", ct);
+        });
+
+        servers.MapDelete("/{id}", async (AppHost host, string id, CancellationToken ct) =>
+        {
+            var removed = host.Instance.McpServers.RemoveAll(s => string.Equals(s.Id, id, StringComparison.OrdinalIgnoreCase));
+            return removed == 0
+                ? Results.NotFound(new OutcomeDto(false, $"No server '{id}'."))
+                : await SaveAndSyncAsync(host, $"MCP server '{id}' removed. Agents that had its tool keep the entry until it is taken away.", ct);
+        });
+
+        servers.MapPost("/{id}/refresh", async (AppHost host, string id, CancellationToken ct) =>
+        {
+            if (host.McpServers?.Find(id) is not { } tool)
+                return Results.NotFound(new OutcomeDto(false, $"No server '{id}'."));
+            var ok = await tool.RefreshAsync(ct);
+            return Results.Ok(new OutcomeDto(ok, ok ? $"{tool.RemoteTools.Count} tool(s) found." : $"Not reachable: {tool.Problem}"));
+        });
+
        // Streamable HTTP lets a server refuse the event stream; this one keeps no sessions.
        app.MapMethods("/mcp", ["GET", "DELETE"], () => Results.StatusCode(StatusCodes.Status405MethodNotAllowed));

@@ -150,6 +194,58 @@ internal static class McpEndpoints
                : Results.NotFound(new OutcomeDto(false, $"No active token '{id}'.")));
    }

+    // ─── external MCP servers (#197) ───
+
+    private static McpServerDto ServerDto(AppHost host, Core.Mcp.McpServerConfig s)
+    {
+        var tool = host.McpServers?.Find(s.Id);
+        return new McpServerDto(s.Id, s.Name, s.Url, Core.Mcp.McpServerTool.NameFor(s.Id), s.Enabled, s.TimeoutSeconds,
+            s.Headers.Keys.Order(StringComparer.OrdinalIgnoreCase).ToList(), s.WithoutApproval,
+            tool?.RemoteTools.Select(t => new McpRemoteToolDto(t.Name, t.Description)).ToList() ?? [],
+            tool?.RefreshedAtUtc, tool?.Problem);
+    }
+
+    /// <summary>Writes the input into the server; headers only where a value was given — an empty value removes one.</summary>
+    private static string? Apply(Core.Mcp.McpServerConfig server, McpServerInputDto input)
+    {
+        if (input.Name is not null)
+            server.Name = input.Name.Trim();
+        if (string.IsNullOrWhiteSpace(server.Name))
+            server.Name = server.Id;
+        if (input.Url is not null)
+        {
+            if (!Uri.TryCreate(input.Url.Trim(), UriKind.Absolute, out var uri) || uri.Scheme is not ("http" or "https"))
+                return "The address must be an http(s) URL.";
+            server.Url = uri.ToString();
+        }
+        if (string.IsNullOrWhiteSpace(server.Url))
+            return "The server needs an address.";
+        if (input.Enabled is { } enabled)
+            server.Enabled = enabled;
+        if (input.TimeoutSeconds is { } timeout)
+            server.TimeoutSeconds = Math.Clamp(timeout, 5, 600);
+        if (input.WithoutApproval is not null)
+            server.WithoutApproval = input.WithoutApproval.Select(o => o.Trim()).Where(o => o.Length > 0).Distinct().ToList();
+        foreach (var (name, value) in input.Headers ?? [])
+        {
+            if (string.IsNullOrWhiteSpace(name) || name.Any(c => c <= ' ' || c == ':'))
+                return $"'{name}' is no header name.";
+            if (string.IsNullOrEmpty(value))
+                server.Headers.Remove(name);
+            else
+                server.Headers[name.Trim()] = value;
+        }
+        return null;
+    }
+
+    private static async Task<IResult> SaveAndSyncAsync(AppHost host, string message, CancellationToken ct)
+    {
+        host.SaveInstance(new App.InstanceChange(App.InstanceChangeKind.Settings));
+        if (host.McpServers is { } connections)
+            await connections.SyncAsync(ct);
+        return Results.Ok(new OutcomeDto(true, message));
+    }
+
    /// <summary>Only the header — never the query string: an address ends up in logs.</summary>
    private static string? BearerToken(HttpRequest request)
    {