fix(converters): preserve user config when writing MCP servers (#479)

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/sync/codex.ts

@@ -1,15 +1,11 @@
 import fs from "fs/promises"
 import path from "path"
 import type { ClaudeHomeConfig } from "../parsers/claude-home"
-import { renderCodexConfig } from "../targets/codex"
+import { mergeCodexConfig, renderCodexConfig } from "../targets/codex"
 import { writeTextSecure } from "../utils/files"
 import { syncCodexCommands } from "./commands"
 import { syncSkills } from "./skills"
 
-const CURRENT_START_MARKER = "# BEGIN compound-plugin Claude Code MCP"
-const CURRENT_END_MARKER = "# END compound-plugin Claude Code MCP"
-const LEGACY_MARKER = "# MCP servers synced from Claude Code"
-
 export async function syncToCodex(
   config: ClaudeHomeConfig,
   outputRoot: string,
@@ -17,52 +13,19 @@ export async function syncToCodex(
   await syncSkills(config.skills, path.join(outputRoot, "skills"))
   await syncCodexCommands(config, outputRoot)
 
-  // Write MCP servers to config.toml (TOML format)
-  if (Object.keys(config.mcpServers).length > 0) {
-    const configPath = path.join(outputRoot, "config.toml")
-    const mcpToml = renderCodexConfig(config.mcpServers)
-    if (!mcpToml) {
-      return
+  // Write MCP servers to config.toml, or clean up stale managed block if none remain
+  const configPath = path.join(outputRoot, "config.toml")
+  let existingContent = ""
+  try {
+    existingContent = await fs.readFile(configPath, "utf-8")
+  } catch (err) {
+    if ((err as NodeJS.ErrnoException).code !== "ENOENT") {
+      throw err
     }
-
-    // Read existing config and merge idempotently
-    let existingContent = ""
-    try {
-      existingContent = await fs.readFile(configPath, "utf-8")
-    } catch (err) {
-      if ((err as NodeJS.ErrnoException).code !== "ENOENT") {
-        throw err
-      }
-    }
-
-    const managedBlock = [
-      CURRENT_START_MARKER,
-      mcpToml.trim(),
-      CURRENT_END_MARKER,
-      "",
-    ].join("\n")
-
-    const withoutCurrentBlock = existingContent.replace(
-      new RegExp(
-        `${escapeForRegex(CURRENT_START_MARKER)}[\\s\\S]*?${escapeForRegex(CURRENT_END_MARKER)}\\n?`,
-        "g",
-      ),
-      "",
-    ).trimEnd()
-
-    const legacyMarkerIndex = withoutCurrentBlock.indexOf(LEGACY_MARKER)
-    const cleaned = legacyMarkerIndex === -1
-      ? withoutCurrentBlock
-      : withoutCurrentBlock.slice(0, legacyMarkerIndex).trimEnd()
-
-    const newContent = cleaned
-      ? `${cleaned}\n\n${managedBlock}`
-      : `${managedBlock}`
-
-    await writeTextSecure(configPath, newContent)
+  }
+  const mcpToml = renderCodexConfig(config.mcpServers)
+  const merged = mergeCodexConfig(existingContent, mcpToml)
+  if (merged !== null) {
+    await writeTextSecure(configPath, merged)
   }
 }
-
-function escapeForRegex(value: string): string {
-  return value.replace(/[.*+?^${}()|[\]\\]/g, "\\$&")
-}