Loop Build

Loop Build — phase 2 of loop-run

Input: an ISSUE-ID (e.g. <TEAM>-<N>). State dir: $LOOP_STATE_DIR/<ISSUE-ID>/ (default ~/.claude/loop-state/<ISSUE-ID>/). Requires spec.md there — if missing, stop and tell the operator to run loop-spec first.

Repo: a lago-front checkout. Two layouts, resolved by loop-run and defined in its ## Layout section — worktree (the default: front/ in the lago monorepo, worktrees in front-worktrees/ beside it) and in-place (the current checkout is the worktree; automatic inside a Conductor workspace, forced with --in-place). Invoked directly without loop-run, resolve it the same way: $CONDUCTOR_WORKSPACE_PATH set or --in-place passed → in-place, else worktree.

Nothing is fetched. spec.md carries the ticket and its sources; the coding styleguide is .agents/docs/frontend-coding-styleguide.md. No Linear, no Notion in this phase.

Modes

• Fresh build: no review.md in the state dir, or it says PASS.
• Fix mode: review.md (or adversarial.md) has verdict FAIL, or ci-failure.md was just written by loop-run — fix ONLY the numbered issues / CI failures listed there, nothing else. Reuse the existing worktree from state.md.

Steps (fresh build)

1. Preflight — the worktree layout creates its workspace, in-place validates the one it was handed:

   worktree layout (all must hold, else STOP and ask the operator):

   • Main docker stack running: docker ps --format '{{.Names}}' | grep lago_front_dev.
   • Local main in front/ up to date: git -C front pull --ff-only origin main. If it fails (dirty checkout, diverged), STOP — never stash, reset, or force.
   • If a front-worktrees/<ISSUE-ID>-* dir already exists from an aborted run, STOP and ask — never delete or force.

   in-place layout:

   FRONT="$(git rev-parse --show-toplevel)"
   [ -x "$FRONT/scripts/iter-budget.sh" ] || { echo "not a lago-front checkout"; exit 1; }
   BRANCH="$(git rev-parse --abbrev-ref HEAD)"
   git fetch origin main

   • Branch guard: STOP if BRANCH is main (or $CONDUCTOR_DEFAULT_BRANCH), or is HEAD (detached). The loop only ever works on a feature branch.
   • git fetch origin main is required: the review phase diffs against origin/main. Fetch only — NEVER pull, rebase, merge, stash or reset (the checkout is the operator's).
   • State conflict: if state.md already exists for this ISSUE-ID and its worktree: is a different path, STOP — that state belongs to another checkout.
   • Docker stack (docker ps --format '{{.Names}}' | grep lago_front_dev): missing → warn only, never block. Gates run on the host.

2. Create the worktree — worktree layout ONLY; in in-place skip this step entirely (nothing is created, lago-worktree is never called). Use the repo's own tool (handles branch, .env copy, pnpm install, port slot, dedicated docker containers, isolated API worktree):

   lago-worktree create <BRANCH> --from-front=main --from-api=main

   (lago-worktree = front/scripts/lago-worktree.sh; if the alias is unavailable, call the script directly.)

   Branch naming — <BRANCH> = <ISSUE-ID>-<topic-slug>: the Linear issue ID first, UPPERCASE, then a short kebab-case slug of the ticket's main topic (3-6 words), e.g. <TEAM>-<N>-swap-customer-overview-connection. No Linear ticket (edge case, e.g. tooling change requested directly) → just the kebab-case topic slug: clean-vite-cache-on-worktree-start. Worktree dir name = branch name. The session stays in the lago root — operate on the worktree via git -C / cd in subshells.

   In in-place the branch is whatever the checkout already carried and is never renamed (git branch -m is forbidden: Conductor persists the branch name in its own database, so a git-side rename desyncs its diff view and its archive-time branch deletion).

3. Record state: write state.md in the state dir (keyed on the bare ISSUE-ID). Key names are load-bearing — loop-review, loop-revise and scripts/loop-restart.sh read them:

   layout: <worktree | in-place>
   worktree: <absolute path — front-worktrees/<BRANCH> in worktree layout, the checkout itself in in-place>
   branch: <BRANCH>
   port: <front port printed by lago-worktree, or $CONDUCTOR_PORT in in-place>
   workspace: <$CONDUCTOR_WORKSPACE_NAME — in-place under Conductor only>
   container: <lago_front_wt_<SAN(branch)> | lago_front_ct_<SAN(workspace)> — omit when there is none>

   SAN = tr '[:upper:]' '[:lower:]' | sed 's/[^a-z0-9]/_/g' on the branch (worktree layout) or on the workspace name (in-place).

4. Plan before code — write plan.md in the state dir. It is the declaration scripts/loop-plan-check.sh and the reviewers compare the diff against; a new file or export that appears in the diff without appearing here triggers the adversarial pass:

   # <ISSUE-ID> plan
   
   ## Files to change
   <path — one line: what changes>
   
   ## New files
   <path — why no existing file could host it, naming the sibling checked; or "none">
   
   ## New exports
   <symbol (path) — who consumes it, why inlining at the call sites is worse; or "none">
   
   ## Estimated size
   <N lines>
   
   ## Comments kept
   <one line per comment the diff keeps: `- <path> — constraint|why-not|trap — "<first words>"`; or "none">
   
   ## Deviations
   <appended during implementation: what changed from the plan above and the one-line reason>

   Start from spec.md ## Files to touch and ## Premises. The default for ## New files, ## New exports and ## Comments kept is "none": write the diff in your head without the abstraction first, and add it only when the inline version is larger. Read .agents/docs/frontend-coding-styleguide.md now, before the first edit.

5. Implement per spec.md and plan.md, inside the worktree: path from state.md only (in in-place that is the cwd). The checks below are capped by scripts/skill-budget.sh.

   <!-- checks:start -->

   1. The plan is the scope. Reality diverges from spec.md or plan.md → append the divergence and its reason to plan.md ## Deviations and continue only if minor; otherwise stop and report. A premise spec.md marks unverified is not built around: build what the code shows, and say so in the report.
   2. Existing mechanism first. Before writing a component, hook, util or handler, search the design-system package (packages/design-system) and src/components/designSystem, the shared modules and the global layers (Apollo error link, toast, router wrappers) for one that already does the job - reuse or extend, never duplicate. When the spec says to mirror a sibling, diff YOUR dependency list against ITS: a dependency the sibling deliberately avoided (an aggregate hook, a wider query) needs a reason in the report. When the component used or touched has an entry in the lago-frontend-patterns skill's index, read it before writing the code.
   3. Translations (translations/base.json): search for an existing label with the same meaning before adding a key; new keys only when nothing fits, following the naming pattern; remove a key when the change removes its last usage.
   4. Comments are declared or deleted. scripts/diff-hygiene.sh flags every comment the diff adds unless plan.md ## Comments kept lists it with its category — constraint (an external rule the reader cannot see, identifier named), why-not (the obvious alternative is wrong), trap (an edit here breaks something elsewhere) — and refuses outright a comment inside a type/interface body, above an import, one that repeats the export's name, or one over 2 lines. Nothing else is a category: "explains the prop", "describes the step", "summarises the function" are deletions. Expect none on a typical diff.
   5. Never as unknown as your way past a type. A shared component's prop type: narrow to Pick<...> of the fields it reads. Two enums with identical members: an exhaustive Record<Source, Target> lookup, the only form that breaks the build when one enum grows.
   6. Copied state goes stale. A config snapshot (MainHeader.Configure), a drawer open({ children }), a child seeding useState from a prop: each copies a mutable value once. Either encode every field it reads in a key (remount / snapshot key) or pass a getter / read the prop. A parent that resets a value the child also stores is a silent wrong-save.
   7. A redirect in a useEffect does not stop its own render: pair every guard effect with an early return null on the same condition (after all hooks), and assert container.firstChild is null.

   <!-- checks:end -->

   GraphQL documents changed → pnpm codegen, and when the worktree's API runs a feature branch, keep only the hunks in src/generated/graphql.tsx that belong to your own operations (CI regenerates from lago-api main).

6. Tests — ALWAYS: after the implementation is complete, invoke the make-tests skill on the changes. NEVER hand-write tests.

7. Gates (run in the worktree, all must pass):

   • pnpm lint (use pnpm lint:fix first if there are formatting issues), pnpm types, pnpm translations:inspect, pnpm translations:ensure-consistency.
   • <front>/scripts/diff-hygiene.sh origin/main <worktree> <state dir>/plan.md — every added comment is declared with a category, none in a refused position. Flagged → delete it (the default) or, for a real constraint/why-not/trap, add its line to ## Comments kept.
   • <front>/scripts/loop-plan-check.sh <worktree> <state dir>/plan.md — every new file / export / re-export is declared. Exit 1 → either delete the abstraction or declare it in plan.md with its reason; never leave it undeclared. Exit 3 (all declared) passes the gate: it is loop-run's signal to run the adversarial pass on what was declared.
   • Scoped jest on the paths make-tests produced/touched. NEVER run the full suite (pnpm test with no path is FORBIDDEN).
   • A jest failure that does not reproduce in isolation or under --runInBand is load/cold-cache flake, not a regression: rerun before diagnosing or consuming a cycle.

8. Report: diff stat, plan.md deviations, gates output summary. Do NOT commit — shipping happens in loop-run after review PASS.