Colon-prefixed output is truncated in VS Code Codex extension

What version of Codex is running?

VS Code Extension v0.4.0

Which model were you using?

gpt-5-high

What platform is your computer?

Darwin 24.6.0 arm64 arm

What steps can reproduce the bug?

1. Install the latest Codex VS Code extension (v0.4.0).
2. Trigger a completion where Codex should output a colon-prefixed string. Example: request Codex to output read:project.
3. Observe the result in the editor.

What is the expected behavior?

The extension should output the full string read:project.

What do you see instead?

Output will be:

read

The word after the colon will be replaced with a newline. This transformation also happens in the prompt you send through the extension.

Additional information

This bug breaks any completion involving key:value syntax, YAML, configs, or namespaces. It appears to be either a token handling or output post-processing issue in the extension itself.