D333 - The command-line engine reads its prompt from standard input

Status: decided Date: 2026-08-27

The engine that borrows an installed coding assistant's session (Kind::Cli) passes the prompt on standard input and reads the reply from standard output. A signed-out command is reported, never signed in, and describe() states that seed and temperature are ignored and the system text is not isolated.

Why: it needs no key, download or accelerator. A prompt carrying examples and a vocabulary sample can exceed the platform's command-line length limit. A tool that must run unattended cannot seize the terminal to open a browser. An engine that dropped request fields quietly would be indistinguishable from one that honoured them.

Rejected:

• The prompt as an argument: fails once it grows past the length limit.
• Interactive login on failure: blocks an unattended run.