# SH0004: The build closed the link at its hello: the token is wrong

Source: https://zafnok.github.io/shuyi-engine/learn/errors/sh0004/

Class: usage, exit code 2.

`attach` (or MCP's `start` with `link`) reached a build listening on the
live link, and said hello with `--token` (`link`'s `token`). The build has another token, so it closed the link and read
nothing more. A build makes a new token each time it starts, unless
`SHUYI_LINK_TOKEN` sets it, and says it in its log line:

```text
shuyi link: listening on 127.0.0.1:7357, token 3f0c9b2e8d1a4c6f9e7b5a3d2c1f0e9d
```

**How to fix it.** Pass the token of the build's latest log line as
`--token` (or `link`'s `token`), then attach again.

For example:

```text
attach: error[SH0004]: the build at 127.0.0.1:7357 closed the link at its hello: the token is wrong
```