feat: add detect-tools utility and Gemini sync with tests

src/sync/gemini.ts

@@ -0,0 +1,76 @@
+import fs from "fs/promises"
+import path from "path"
+import type { ClaudeHomeConfig } from "../parsers/claude-home"
+import type { ClaudeMcpServer } from "../types/claude"
+import { forceSymlink, isValidSkillName } from "../utils/symlink"
+
+type GeminiMcpServer = {
+  command?: string
+  args?: string[]
+  url?: string
+  env?: Record<string, string>
+  headers?: Record<string, string>
+}
+
+export async function syncToGemini(
+  config: ClaudeHomeConfig,
+  outputRoot: string,
+): Promise<void> {
+  const skillsDir = path.join(outputRoot, "skills")
+  await fs.mkdir(skillsDir, { recursive: true })
+
+  for (const skill of config.skills) {
+    if (!isValidSkillName(skill.name)) {
+      console.warn(`Skipping skill with invalid name: ${skill.name}`)
+      continue
+    }
+    const target = path.join(skillsDir, skill.name)
+    await forceSymlink(skill.sourceDir, target)
+  }
+
+  if (Object.keys(config.mcpServers).length > 0) {
+    const settingsPath = path.join(outputRoot, "settings.json")
+    const existing = await readJsonSafe(settingsPath)
+    const converted = convertMcpForGemini(config.mcpServers)
+    const existingMcp =
+      existing.mcpServers && typeof existing.mcpServers === "object"
+        ? (existing.mcpServers as Record<string, unknown>)
+        : {}
+    const merged = {
+      ...existing,
+      mcpServers: { ...existingMcp, ...converted },
+    }
+    await fs.writeFile(settingsPath, JSON.stringify(merged, null, 2), { mode: 0o600 })
+  }
+}
+
+async function readJsonSafe(filePath: string): Promise<Record<string, unknown>> {
+  try {
+    const content = await fs.readFile(filePath, "utf-8")
+    return JSON.parse(content) as Record<string, unknown>
+  } catch (err) {
+    if ((err as NodeJS.ErrnoException).code === "ENOENT") {
+      return {}
+    }
+    throw err
+  }
+}
+
+function convertMcpForGemini(
+  servers: Record<string, ClaudeMcpServer>,
+): Record<string, GeminiMcpServer> {
+  const result: Record<string, GeminiMcpServer> = {}
+  for (const [name, server] of Object.entries(servers)) {
+    const entry: GeminiMcpServer = {}
+    if (server.command) {
+      entry.command = server.command
+      if (server.args && server.args.length > 0) entry.args = server.args
+      if (server.env && Object.keys(server.env).length > 0) entry.env = server.env
+    } else if (server.url) {
+      entry.url = server.url
+      if (server.headers && Object.keys(server.headers).length > 0) entry.headers = server.headers
+    }
+    result[name] = entry
+  }
+  return result
+}