x/tools/gopls: add a 'format' mcp tool

[findleyr]

Frequently, Gemini CLI fails to format Go code.

We should add a format tool to gopls MCP, with instructions to run it after every edit.

[gabyhelp]

Related Issues

• x/tools/gopls: allow more formatter options #74678

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[myaaaaaaaaa]

How about making it into a catch-all "cleanup AI code" tool? It could clean up various other things that Gemini tends to miss:

• goimports to fix import statements
• Rewriting b.N benchmarks into b.Loop()
• for i := 0; i < n; i++ into for i := range n

Ideally, it should also be made available from the command line, so that Jules can use it too.

[findleyr]

@myaaaaaaaaa can Jules not call mcp servers? gopls mcp is a headless MCP.

There's already a diagnostics tool that serves modernizers, so you should be able to instruct any MCP-powered agent to check that.

[myaaaaaaaaa]

can Jules not call mcp servers? gopls mcp is a headless MCP.

I'm not sure. There's no option to add custom MCP servers. On the other hand, maybe you're right, not having the official Go MCP server preinstalled is an issue on the Jules side.

There's already a diagnostics tool that serves modernizers, so you should be able to instruct any MCP-powered agent to check that.

But is it pre-instructed to run them after every edit, like you're proposing with the formatter? I think there's a case to be made that this should be the default behavior for coding agents, since they'll otherwise tend to write outdated code.