MCP config using type "stdio" causes opaque TUI bootstrap server errors in 1.15.x #28625

Describe the bug

After upgrading to OpenCode 1.15.x, an existing opencode.json MCP config that used the previous/Claude-style stdio shape caused the TUI to fail during bootstrap with opaque request failures instead of a config validation message.

The user-facing error was:

Error: 4 of 5 requests failed: config.providers: Unexpected server error. Check server logs for details.; provider.list: Unexpected server error. Check server logs for details.; app.agents: Unexpected server error. Check server logs for details.; config.get: Unexpected server error. Check server logs for details.

Server logs had the actual root cause:

ConfigInvalidError
SchemaError: Expected { readonly "type": "local", ... } | { readonly "type": "remote", ... }, got {"type":"stdio","command":"python","args":["..."]}
  at ["mcp"]["dbpedia-lookup"]
Missing key
  at ["mcp"]["dbpedia-lookup"]["enabled"]

Config that triggers it

{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "local-server": {
      "type": "stdio",
      "command": "python",
      "args": ["/path/to/server.py"]
    }
  }
}

Working config

{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "local-server": {
      "type": "local",
      "command": ["python", "/path/to/server.py"],
      "enabled": true
    }
  }
}

Expected behavior

Either:

1. accept/migrate the old type: "stdio" + command + args form for compatibility, or
2. surface the schema validation error directly in the TUI instead of the higher-level config.providers / provider.list / app.agents / config.get unexpected server errors.

Environment

• OpenCode version observed: 1.15.0, then upgraded to 1.15.6
• Install method: curl updater
• macOS

Notes

This is especially easy to hit for users syncing MCP config from Cursor/Claude-style mcpServers, where local stdio servers commonly use type: "stdio", command, and args.