Setup asks for the Harness, Model and Effort #393

Parent

#136

What to build

Setup asks which Harness to use, then the Model and Effort for it, and writes the answers to the User config.

• The Harness question. It always lists both Harnesses, marking any that isn't installed, for example codex (not installed). It refuses a Harness that isn't installed and asks again. The default answer is the installed Harness, or claude when both are installed.
• Codex for now. Until Codex sessions are supported, Codex is listed but marked and refused the same way, with "not supported yet". The "Setup offers Codex" Ticket turns it on.
• Model and Effort questions. These are asked only for the chosen Harness. Each shows the current value as its default answer, and a blank answer means the Harness's own default.
• Checking answers. Answers are checked the way a Run checks them (Choose the Harness, Model and Effort a Command runs on (Claude Code or Codex) #136, see the Harness, Model and Effort Ticket). A rejected answer is asked again with the reason shown.
• Writing the file. The other Harness's section is written with blank values, so the file shows every setting. Setup over an existing User config keeps its values and comments and adds the keys it lacks, as it does today. With no terminal, Setup writes the defaults without asking.

Acceptance criteria

• From a terminal, Setup asks the Harness question with both Harnesses listed, and marks any that isn't on PATH.
• Choosing a Harness that isn't installed, or isn't supported yet, is refused and asked again.
• The default answer is the installed Harness, or claude when both are installed.
• Model and Effort are asked only for the chosen Harness, with the current values as defaults and blank meaning the Harness's default.
• A Claude Model that the test call rejects is asked again, with Claude's error shown.
• The written User config has [harness], [harness.claude] and [harness.codex] with every key present.
• Setup over an existing User config keeps its values and comments.
• Setup with no terminal writes the Harness settings at their defaults.

Blocked by

• Choose the Harness, Model and Effort on the command line and in the User config, with Claude #392