fg-tdd

name	fg-tdd
description	Toggle forge's TDD mode on/off — a persistent setting in .forge/config.json. `fg-tdd on`/`off` set it; no arg shows the current state. When on, fg-ask defaults to asking per task and fg-run runs test-first. On-demand utility outside the loop. Use in contexts like 'forge tdd', 'tdd on', 'tdd off', 'TDD 켜', 'TDD 꺼', 'tdd 상태'.

fg-tdd — toggle TDD mode (outside the loop)

This is not a stage of the forge loop. It is a tiny on-demand utility that flips one persistent project setting: whether forge defaults to test-driven development. It reads and writes only .forge/config.json — it never touches the active slot, backlog, executed, or done state.

.forge/config.json is a deliberate global exemption from branch-root resolution (see ${CLAUDE_PLUGIN_ROOT}/skills/fg-run/FORGE-ROOT.md / ADR-0011): it is always the top-level .forge/config.json on every branch, never .forge/branch/<branch>/config.json. Reason — it holds defaultBranch, which the root-resolution rule itself must read before it can resolve anything, and tdd is a project-wide setting. So fg-tdd writes the global path as-is; do not "fix" it to resolve the branch root.

Language: This skill file is authored in English, but you MUST write every message shown to the user — questions, menus, status/next-step lines, and handoff text — in the user's language (detect it from the user's own messages), never mirroring this file's English.

What it does

• fg-tdd on → set tdd: true in .forge/config.json.
• fg-tdd off → set tdd: false.
• fg-tdd (no argument) → report the current state in one line (e.g. "TDD mode: on" / "off"). Do not change anything.

The config file — .forge/config.json

A git-tracked JSON settings file (lazily created on first write; .gitignore whitelists !.forge/config.json). It holds forge's persistent project settings — tdd (the key this skill manages) and, optionally, defaultBranch (read by branch-root resolution; see FORGE-ROOT.md / ADR-0011) and eco (the fg-eco delegated-model toggle; ADR-0014). Example of the lazily-created default:

{
  "tdd": false
}

• Default is false (off) — if the file doesn't exist, treat tdd as false.
• When writing, preserve any other keys already in the file (read → set tdd → write back); only change tdd. Keep the JSON valid.
• This is a team-shared project default (tracked in git): "this project develops TDD-style." An individual task can still override it — fg-ask asks per task and records the choice on the plan (<!-- tdd: on|off -->), defaulting to this setting.

How the setting is used (for reference — not this skill's job)

• fg-ask reads tdd as the default when it asks, at the start of grilling, whether to build the task TDD-style, and records <!-- tdd: on|off --> on the plan.
• fg-run runs the plan test-first when its tdd marker is on (each slice: write a failing test → implement → make it pass).

fg-tdd only flips the default; it does not start any work.

Handoff

After toggling, state the new value in one line and, if relevant, note that it takes effect on the next fg-ask (the default it offers) — tasks already planned keep the tdd: marker they were created with. There is no loop next-step; fg-tdd is a side utility.

Document impact

• Creates/updates .forge/config.json (the tdd key only; git-tracked). Touches nothing else.