dotfiles/.agents/mcp/index.ts

#!/usr/bin/env node
/**
 * all-agents MCP server — shared agent infrastructure over the Model Context Protocol.
 *
 * Prompts and tools are auto-discovered from sibling directories:
 *   ../agents/*.md   → slash-command prompts (requires description: frontmatter)
 *   ../skills/*.md   → model-controlled tools (requires description: frontmatter)
 *
 * Agent/skill bodies are read from disk at invocation time — editing any .md
 * file takes effect immediately without restarting the server.
 *
 * Frontmatter fields:
 *   description  (required) — routing description for the prompt/tool
 *   toolName     (skills only, optional) — override the derived tool name
 *                  default: load_<basename> (e.g. research-methodology.md → load_research-methodology)
 *
 * Not handled here (stays bespoke):
 *   hooks/       — MCP has no lifecycle intercept primitive
 *   AGENTS.md    — always-on bootstrap; model needs it before tools/list
 *
 * Run:  node --experimental-strip-types .agents/mcp/index.ts
 * Config: ~/.vscode-server/data/User/mcp.json (Copilot),
 *         ~/.config/opencode/opencode.json (OpenCode global)
 */
import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
import { readFileSync, readdirSync } from "node:fs";
import { basename, resolve } from "node:path";
import { z } from "zod";

const agentsDir = resolve(import.meta.dirname, "../agents");
const skillsDir = resolve(import.meta.dirname, "../skills");

interface ParsedFile {
  description: string;
  toolName?: string | undefined;
  body: string;
}

/** Parse YAML frontmatter and return description, optional toolName, and body. */
function parseFrontmatter(content: string): ParsedFile {
  const lines = content.split("\n");
  if (lines[0] !== "---") return { description: "", body: content.trim() };
  const end = lines.indexOf("---", 1);
  if (end === -1) return { description: "", body: content.trim() };

  const frontmatter = lines.slice(1, end).join("\n");
  const body = lines
    .slice(end + 1)
    .join("\n")
    .trim();

  // Simple single-line or quoted-string extraction for description and toolName
  const descMatch = frontmatter.match(
    /^description:\s*['"]?([\s\S]*?)['"]?\s*$/m,
  );
  const toolMatch = frontmatter.match(/^toolName:\s*['"]?([^'"]+)['"]?\s*$/m);

  // Handle multi-line description values (block scalar or wrapped string)
  let description = "";
  if (descMatch) {
    // If the match includes a leading quote, strip matching quotes
    const raw = frontmatter.match(/^description:\s*(['"])([\s\S]*?)\1\s*$/m);
    description = raw ? raw[2]?.trim() ?? '' : descMatch[1]?.trim() ?? '';
  }

  return {
    description,
    toolName: toolMatch?.[1]?.trim(),
    body,
  };
}

function stripLocalBlocks(body: string): string {
  return body.replace(/<!-- @local -->[\s\S]*?<!-- @endlocal -->\n?/g, "");
}

function stripCloudBlocks(body: string): string {
  return body.replace(/<!-- @cloud -->[\s\S]*?<!-- @endcloud -->\n?/g, "");
}

/**
 * Returns 'local' when the MCP client identifies as `opencode` (local-model
 * harness), 'cloud' for any other client (Copilot / VS Code etc.).
 */
function getClientProfile(): "local" | "cloud" {
  const info = server.server.getClientVersion();
  return info?.name === "opencode" ? "local" : "cloud";
}

function applyClientProfile(body: string): string {
  return getClientProfile() === "local"
    ? stripCloudBlocks(body)
    : stripLocalBlocks(body);
}

const server = new McpServer({ name: "all-agents", version: "1.0.0" });

// ── Prompts (auto-discovered from ../agents/*.md) ─────────────────────────────

const agentFiles = readdirSync(agentsDir).filter(
  (f) => f.endsWith(".md") && f !== "AGENTS.md",
);

for (const file of agentFiles) {
  const name = basename(file, ".md");
  const { description, body } = parseFrontmatter(
    readFileSync(resolve(agentsDir, file), "utf8"),
  );
  if (!description) {
    process.stderr.write(
      `[all-agents] WARNING: ${file} has no description — skipping\n`,
    );
    continue;
  }

  const argKey =
    name === "orchestrator" ? "goal" : name === "brainstorm" ? "topic" : "task";
  const argDesc =
    name === "orchestrator"
      ? "The high-level goal to decompose"
      : name === "brainstorm"
        ? "The problem or decision to brainstorm"
        : "The specific task or question";

  server.registerPrompt(
    name,
    {
      description,
      argsSchema: { [argKey]: z.string().optional().describe(argDesc) },
    },
    (args: Record<string, string | undefined>) => {
      const input = args[argKey];
      const agentBody = applyClientProfile(
        parseFrontmatter(readFileSync(resolve(agentsDir, file), "utf8")).body,
      );
      return {
        messages: [
          {
            role: "user" as const,
            content: {
              type: "text" as const,
              text: input ? `${agentBody}\n\n${input}` : agentBody,
            },
          },
        ],
      };
    },
  );
}

// ── Tools (auto-discovered from ../skills/*.md) ───────────────────────────────

const skillFiles = readdirSync(skillsDir).filter((f) => f.endsWith(".md"));

for (const file of skillFiles) {
  const name = basename(file, ".md");
  const { description, toolName } = parseFrontmatter(
    readFileSync(resolve(skillsDir, file), "utf8"),
  );
  if (!description) {
    process.stderr.write(
      `[all-agents] WARNING: ${file} has no description — skipping\n`,
    );
    continue;
  }

  server.registerTool(toolName ?? `load_${name}`, { description }, () => ({
    content: [
      {
        type: "text" as const,
        text: parseFrontmatter(readFileSync(resolve(skillsDir, file), "utf8"))
          .body,
      },
    ],
  }));
}

// ── Resources (no-op to satisfy resources/list) ──────────────────────────────

server.registerResource(
  "noop",
  "noop://noop",
  { description: "No-op resource (satisfies resources/list)" },
  () => ({
    contents: [{ uri: "noop://noop", mimeType: "text/plain", text: "" }],
  }),
);

// ── Connect ───────────────────────────────────────────────────────────────────

const transport = new StdioServerTransport();
try {
  await server.connect(transport);
} catch (err) {
  process.stderr.write(
    `MCP connect failed: ${err instanceof Error ? err.message : String(err)}\n`,
  );
  process.exit(1);
}