# SH3005: The game's tool program didn't build, or stopped before it answered

Source: https://zafnok.github.io/shuyi-engine/learn/errors/sh3005/

Class: operation, exit code 1.

The MCP server (`shuyi mcp`) runs the game's tool program (`shuyi.ron`'s
`game`) with `cargo run` to answer a tool that runs the game, and keeps
it running for the session. The program didn't build, or it stopped
before it answered: a compile error, a panic in the game, or a game whose
engine is older than the server's. The message ends with the last of its
output.

A project in another cargo workspace than the server's (a worktree, say)
is answered by the project's own MCP server, built from that workspace's
engine: its `command` and `mcp`. When that server didn't build, or
stopped, the message names it ("the project's own server") and ends with
the last of its output: the compile error is in the engine or the game
of that workspace.

**How to fix it.** Read the output in the message, fix the game's code
(or its engine's version, or the workspace's engine), then call the tool
again: the server builds it again. A session that was running has ended:
call `start` again.

For example:

```text
start: error[SH3005]: the game's tool program stopped before it answered (exit code 101): error[E0425]: cannot find value `hero` in this scope
```