Playa/extensions/Volcanic.AgenticCore.Extensions.ClaudeCode/ClaudeArgs.cs

using System.Text.Encodings.Web;
using System.Text.Json;
using System.Text.Json.Nodes;

namespace Volcanic.AgenticCore.Extensions.ClaudeCode;

/// <summary>Everything the argv builder needs for one request.</summary>
/// <param name="Model">The alias passed to <c>--model</c>.</param>
/// <param name="Effort">The <c>--effort</c> level, or null to omit the flag.</param>
/// <param name="SystemPromptPath">File handed to <c>--system-prompt-file</c>.</param>
/// <param name="CatalogPath">Tool catalogue for the bridge; null when the request carries no tools (empty MCP config).</param>
/// <param name="ViolationPath">Marker the bridge creates on a <c>tools/call</c>.</param>
/// <param name="ReadyPath">Marker the bridge creates after <c>tools/list</c>.</param>
/// <param name="BridgeDllPath">The bridge assembly <c>dotnet</c> runs.</param>
/// <param name="DotnetPath">The dotnet muxer.</param>
/// <param name="ServerName">The MCP server name; tools are exposed as <c>mcp__&lt;ServerName&gt;__&lt;alias&gt;</c>.</param>
public sealed record ClaudeArgsInput(
    string Model,
    string? Effort,
    string SystemPromptPath,
    string? CatalogPath = null,
    string? ViolationPath = null,
    string? ReadyPath = null,
    string? BridgeDllPath = null,
    string? DotnetPath = null,
    string ServerName = ToolCatalog.DefaultServerName);

/// <summary>Builds the exact <c>claude</c> argv and the allow-listed child environment.</summary>
public static class ClaudeArgs
{
    // Empty setting sources plus explicit settings preserve subscription authentication while suppressing user and
    // project customisations. --bare would disable OAuth, and --safe-mode would disable the proposal MCP server.
    // totalTokensReminder would otherwise append a changing reminder that breaks append-only cache reuse, and the
    // built-in agents-md plugin loads regardless of setting sources unless disabled here.
    public const string Settings = "{\"disableAllHooks\":true,\"autoMemoryEnabled\":false,\"totalTokensReminder\":\"off\",\"enabledPlugins\":{\"agents-md@builtin\":false}}";
    public const string EmptyMcpConfig = "{\"mcpServers\":{}}";

    public const string CatalogVariable = "VOLCANIC_CLAUDE_TOOL_CATALOG";
    public const string ViolationVariable = "VOLCANIC_CLAUDE_TOOL_VIOLATION";
    public const string ReadyVariable = "VOLCANIC_CLAUDE_TOOL_READY";
    public const string MaxOutputTokensVariable = "CLAUDE_CODE_MAX_OUTPUT_TOKENS";

    private static readonly JsonSerializerOptions ConfigOptions = new() { Encoder = JavaScriptEncoder.UnsafeRelaxedJsonEscaping };

    /// <summary>Variables forwarded from the parent environment (compared case-insensitively). <c>LC_*</c> is forwarded as a prefix.</summary>
    public static readonly IReadOnlyList<string> AllowedVariables =
    [
        "HOME", "PATH", "USER", "LOGNAME", "SHELL", "LANG", "TMPDIR", "TMP", "TEMP",
        // A relocated Claude Code configuration directory holds the login to use.
        "CLAUDE_CONFIG_DIR",
        "HTTP_PROXY", "HTTPS_PROXY", "NO_PROXY",
        // The extra CA bundle a TLS-inspecting proxy requires.
        "NODE_EXTRA_CA_CERTS",
        "SystemRoot", "USERPROFILE", "APPDATA", "LOCALAPPDATA", "ComSpec", "PATHEXT",
    ];

    /// <summary>Variables that must never reach a Claude child: this provider is subscription-only.</summary>
    public static readonly IReadOnlyList<string> DeniedVariables =
    [
        "ANTHROPIC_API_KEY", "ANTHROPIC_AUTH_TOKEN", "ANTHROPIC_BASE_URL",
        "CLAUDE_CODE_OAUTH_TOKEN", "CLAUDE_CODE_USE_BEDROCK", "CLAUDE_CODE_USE_VERTEX",
    ];

    /// <summary>The complete argv (without the executable), in the fixed order Claude Code is validated against.</summary>
    public static IReadOnlyList<string> Build(ClaudeArgsInput input)
    {
        ArgumentNullException.ThrowIfNull(input);
        if (string.IsNullOrWhiteSpace(input.Model)) throw new ArgumentException("A model alias is required.", nameof(input));
        if (string.IsNullOrWhiteSpace(input.SystemPromptPath)) throw new ArgumentException("A system prompt file is required.", nameof(input));

        var args = new List<string>
        {
            "-p",
            "--setting-sources", "",
            "--settings", Settings,
            "--disable-slash-commands",
            "--strict-mcp-config",
            "--permission-mode", "dontAsk",
            "--no-chrome",
            "--no-session-persistence",
            "--prompt-suggestions", "false",
            "--mcp-config", BuildMcpConfig(input),
            "--tools", "",
            "--model", input.Model,
        };
        if (input.Effort is not null)
        {
            args.Add("--effort");
            args.Add(input.Effort);
        }
        // Claude 5 and Opus 4.7+ return thinking blocks whose text is empty unless summarized display is requested.
        args.Add("--thinking-display");
        args.Add("summarized");
        args.Add("--input-format");
        args.Add("stream-json");
        args.Add("--output-format");
        args.Add("stream-json");
        args.Add("--include-partial-messages");
        args.Add("--verbose");
        // The system prompt stays out of the argv, away from command-line size limits.
        args.Add("--system-prompt-file");
        args.Add(input.SystemPromptPath);
        return args;
    }

    /// <summary>The <c>--mcp-config</c> JSON: the bridge as the only server, or no servers at all without tools.</summary>
    public static string BuildMcpConfig(ClaudeArgsInput input)
    {
        ArgumentNullException.ThrowIfNull(input);
        if (input.CatalogPath is null) return EmptyMcpConfig;
        if (string.IsNullOrWhiteSpace(input.BridgeDllPath))
            throw new ClaudeCodeException(ClaudeCodeException.Codes.McpStartup, "The proposal MCP bridge assembly was not located; tools cannot be exposed to Claude Code");
        if (string.IsNullOrWhiteSpace(input.DotnetPath))
            throw new ClaudeCodeException(ClaudeCodeException.Codes.McpStartup, "The dotnet muxer was not located; the proposal MCP bridge cannot be launched");
        var env = new JsonObject { [CatalogVariable] = input.CatalogPath };
        if (input.ViolationPath is not null) env[ViolationVariable] = input.ViolationPath;
        if (input.ReadyPath is not null) env[ReadyVariable] = input.ReadyPath;
        var config = new JsonObject
        {
            ["mcpServers"] = new JsonObject
            {
                [input.ServerName] = new JsonObject
                {
                    ["command"] = input.DotnetPath,
                    ["args"] = new JsonArray(input.BridgeDllPath),
                    ["env"] = env,
                },
            },
        };
        return config.ToJsonString(ConfigOptions);
    }

    /// <summary>The name of a denied variable present in <paramref name="parentEnv"/>, or null.</summary>
    public static string? FindDeniedVariable(IReadOnlyDictionary<string, string?> parentEnv)
    {
        ArgumentNullException.ThrowIfNull(parentEnv);
        foreach (var (name, value) in parentEnv)
        {
            if (value is null) continue;
            if (DeniedVariables.Any(denied => string.Equals(denied, name, StringComparison.OrdinalIgnoreCase))) return name;
        }
        return null;
    }

    /// <summary>
    /// The complete environment a Claude child receives: the allow-listed parent variables plus the pinned ones.
    /// Throws <c>auth</c> when the parent process carries API-key or third-party-provider authentication.
    /// </summary>
    public static IReadOnlyDictionary<string, string> BuildEnvironment(IReadOnlyDictionary<string, string?> parentEnv, int maxOutputTokens)
    {
        ArgumentNullException.ThrowIfNull(parentEnv);
        if (FindDeniedVariable(parentEnv) is { } denied)
            throw new ClaudeCodeException(ClaudeCodeException.Codes.Auth,
                $"{denied} is set; the Claude Code provider only supports subscription authentication and never forwards API-key or third-party credentials. Unset it to use this provider");
        return AllowListed(parentEnv, maxOutputTokens);
    }

    /// <summary>The allow-listed environment without the denial check (used by diagnostics that only probe the CLI).</summary>
    public static IReadOnlyDictionary<string, string> AllowListed(IReadOnlyDictionary<string, string?> parentEnv, int? maxOutputTokens)
    {
        ArgumentNullException.ThrowIfNull(parentEnv);
        var env = new Dictionary<string, string>(StringComparer.Ordinal);
        foreach (var (name, value) in parentEnv)
        {
            if (value is null) continue;
            var allowed = name.StartsWith("LC_", StringComparison.Ordinal)
                          || AllowedVariables.Any(a => string.Equals(a, name, StringComparison.OrdinalIgnoreCase));
            if (allowed) env[name] = value;
        }
        env["CLAUDE_CODE_DISABLE_AUTO_MEMORY"] = "1";
        // Claude Code collects git status, log and user.name at startup for a default system prompt this provider
        // replaces. Run in the user's project, that status can execute a configured git clean filter.
        env["CLAUDE_CODE_DISABLE_GIT_INSTRUCTIONS"] = "1";
        env["CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC"] = "1";
        // The core owns compaction. Given a transcript near its limit, Claude Code would otherwise compact it itself.
        env["DISABLE_COMPACT"] = "1";
        if (maxOutputTokens is { } tokens) env[MaxOutputTokensVariable] = tokens.ToString(System.Globalization.CultureInfo.InvariantCulture);
        return env;
    }

    /// <summary>The current process environment as a dictionary.</summary>
    public static IReadOnlyDictionary<string, string?> CurrentEnvironment()
    {
        var env = new Dictionary<string, string?>(StringComparer.Ordinal);
        foreach (System.Collections.DictionaryEntry entry in Environment.GetEnvironmentVariables())
            env[(string)entry.Key] = entry.Value as string;
        return env;
    }
}

/// <summary>Finds the bridge assembly and the dotnet muxer that runs it.</summary>
public static class BridgeLocator
{
    public const string BridgeFileName = "Volcanic.AgenticCore.Extensions.ClaudeCode.Bridge.dll";

    /// <summary>The bridge dll next to the host, else next to this assembly; null when neither exists.</summary>
    public static string? FindBridgeDll()
    {
        var candidates = new List<string> { Path.Combine(AppContext.BaseDirectory, BridgeFileName) };
        var assemblyDirectory = SafeDirectory(typeof(BridgeLocator).Assembly.Location);
        if (assemblyDirectory is not null) candidates.Add(Path.Combine(assemblyDirectory, BridgeFileName));
        return candidates.FirstOrDefault(File.Exists);
    }

    /// <summary>The dotnet muxer: the current process when it is dotnet, else <c>dotnet</c> on PATH, else <c>DOTNET_ROOT/dotnet</c>.</summary>
    public static string? FindDotnet(Func<string, string?> getEnv)
    {
        ArgumentNullException.ThrowIfNull(getEnv);
        var processPath = Environment.ProcessPath;
        if (processPath is not null)
        {
            var name = Path.GetFileNameWithoutExtension(processPath);
            if (string.Equals(name, "dotnet", StringComparison.OrdinalIgnoreCase) && File.Exists(processPath)) return processPath;
        }
        var names = OperatingSystem.IsWindows() ? new[] { "dotnet.exe" } : new[] { "dotnet" };
        foreach (var directory in (getEnv("PATH") ?? "").Split(Path.PathSeparator, StringSplitOptions.RemoveEmptyEntries))
        {
            foreach (var name in names)
            {
                var candidate = Path.Combine(directory, name);
                if (File.Exists(candidate)) return candidate;
            }
        }
        var root = getEnv("DOTNET_ROOT");
        if (!string.IsNullOrWhiteSpace(root))
        {
            foreach (var name in names)
            {
                var candidate = Path.Combine(root, name);
                if (File.Exists(candidate)) return candidate;
            }
        }
        return null;
    }

    private static string? SafeDirectory(string location)
    {
        if (string.IsNullOrEmpty(location)) return null;
        try
        {
            return Path.GetDirectoryName(location);
        }
        catch (ArgumentException)
        {
            return null;
        }
    }
}