[BUG]: It looks like codebook is reporting INFO logs as ERROR logs in Helix

[ghuh]

Issue Description

I'm getting a bunch of these messages in my Helix logs. Codebook seems to be working fine, so I'm not sure there is a functional issue. It just makes it hard to track down other errors when I see these all over the place.

2025-11-12T22:41:42.626 helix_lsp::transport [ERROR] codebook err <- "[codebook_lsp] INFO: Starting Codebook Language Server v0.3.17-release...\n"
2025-11-12T22:41:42.626 helix_lsp::transport [ERROR] codebook err <- "[codebook_config] INFO: No project config found, using default\n"
2025-11-12T22:41:42.626 helix_lsp::transport [ERROR] codebook err <- "[codebook_downloader] INFO: Cache folder at: \"/var/folders/f_/v1bqrc3s5m5513kry78x82j80000gn/T/codebook\"\n"

My helix_languages.toml is normal

[language-server.codebook]
command = "codebook-lsp"
args = ["serve"]

and I just add codebook to all my language-servers

helix 25.07.1 (a05c151b)

Operating System

macOS

Editor

Helix

Codebook Version

0.3.17

Configuration

Steps to Reproduce

:log-open

Expected Behavior

I'd expect those as INFO logs, not ERROR

Actual Behavior

ERROR logs in Helix

Code Sample

Log Output

Additional Context

No response

[blopker]

Hey! Thanks for the report. I'll be honest, I'm not familiar with how every editor handles logging, so this is helpful.

I think the issue is that logs are printed to stderr. This works for some editors, but it seems like others, maybe Helix, uses a LSP logging API.

I'll need to experiment, and maybe add a command line flag.

Can @copilot explain? (Does that work?)

[the-mikedavis]

Yeah, we print anything a language server prints on stderr as an error log https://github.com/helix-editor/helix/blob/948ac05aa0db64e0e5d00710db36eb244076e988/helix-lsp/src/transport.rs#L146-L158

Lots of servers use stderr for logging so I wonder if we should ignore stderr logs by default instead.

[blopker]

Thanks for the info @the-mikedavis. I refreshed my memory with how Codebook logging works specifically.

When the server first starts up, the handshake with Helix has not been initialized yet, so using the window/logMessage protocol isn't available yet. However, important logs may still need visibility. So Codebook sends all logs to stderr, while also buffering those logs into memory. Once the initialization handshake happens (if it gets that far), Codebook then switches to window/logMessage. When the switch happens, the logger stops using stderr and flushes the pre-handshake log buffer to window/logMessage. All future logs are sent to window/logMessage.

This is something I kinda just came up with as I didn't see much consistency among other LSPs around how this pre-initialization logging is handled.

My question is: How does Helix handle window/logMessage messages?. Do they also get sent to this :log-open file, or into some LSP-specific log? I see they are handled differently, but it's unclear to me how the user accesses them.

Depending on the answer, I think one solution would be to only write pre-initialization logs to stderr if they are actually errors, like warn or error level, by default. Info logs can be written out later exclusively to window/logMessage. This could help cut down the noise to the :log-open log.

[blopker]

Here's a potential fix: https://github.com/blopker/codebook/pull/158/files. When the server is not running in a tty, then only send important logs to stderr.

[blopker]

I've published the mentioned change in v0.3.18. Let me know if it's not working as expected!

[ghuh]

So far it looks like it fixed it to me. Thanks!