Windows: /mcp prints taskkill “SUCCESS” process termination logs

I encountered the same problem.

Same issue:

<img width="1068" height="468" alt="Image" src="https://github.com/user-attachments/assets/897f756a-ae5f-4513-9bbe-84e2c297a122" />

<img width="752" height="555" alt="Image" src="https://github.com/user-attachments/assets/600fa9bc-6a7c-4059-9787-ed2f50eafe02" />

Relevant code:

The Windows termination path currently appears to invoke taskkill without redirecting its stdio, see codex-rs/rmcp-client/src/stdio_server_launcher.rs:

#[cfg(windows)]
fn terminate(&self) {
    let _ = std::process::Command::new("taskkill")
        .arg("/PID")
        .arg(self.pid.to_string())
        .arg("/T")
        .arg("/F")
        .status();
}

Since no stdio is specified, taskkill inherits Codex's stdout/stderr. As a result, taskkill status messages are printed directly into the terminal used by the TUI.

Possible fix:

Redirect the taskkill process stdio to null:

#[cfg(windows)]
fn terminate(&self) {
    use std::process::{Command, Stdio};

    let _ = Command::new("taskkill")
        .arg("/PID")
        .arg(self.pid.to_string())
        .arg("/T")
        .arg("/F")
        .stdin(Stdio::null())
        .stdout(Stdio::null())
        .stderr(Stdio::null())
        .status();
}

Optionally, also set CREATE_NO_WINDOW on Windows:

#[cfg(windows)]
fn terminate(&self) {
    use std::os::windows::process::CommandExt;
    use std::process::{Command, Stdio};

    const CREATE_NO_WINDOW: u32 = 0x08000000;

    let _ = Command::new("taskkill")
        .arg("/PID")
        .arg(self.pid.to_string())
        .arg("/T")
        .arg("/F")
        .stdin(Stdio::null())
        .stdout(Stdio::null())
        .stderr(Stdio::null())
        .creation_flags(CREATE_NO_WINDOW)
        .status();
}

I prepared a possible fix: EurekaMXZ/codex@134409d

However, I am unable to create a Pull Request for this commit, as it only allows invited collaborators to do so.

If this approach matches the intended direction, I’d be happy to open an invited PR.

@etraut-openai Please fix this bug. Thank you so much!

<img width="895" height="318" alt="Image" src="https://github.com/user-attachments/assets/9837e2e1-ad71-4a62-8c34-513bde135a37" />

Same problem

Same. thread ID 019df5b9-d5f8-77a3-8629-36c48d1879b1

Same... version codex-cli 0.128.0

<img width="1214" height="182" alt="Image" src="https://github.com/user-attachments/assets/692a24ee-18ce-438a-a2a6-8ad6f67dc205" />

@rhan-oai Please fix this bug. Thank you so much!

@fcoury-oai Please fix this bug. Thank you so much!

Fixing this bug could still take a long time; this repository does not accept PRs from external contributors, and there are currently over 3,000 open issues.

Currently, in the latest version of Codex, if this issue occurs, you can resize the terminal window; this triggers a re-layout of the Codex TUI, thereby clearing the stdout output by taskkill that has leaked into the TUI.

As of today (May 10) the issue is still present for me and triggers regularly

<img width="1052" height="599" alt="Image" src="https://github.com/user-attachments/assets/4b8eca3f-cf78-4f48-8eff-b070de78466e" />