build — implement spec

Single-thread native plan→execute. You are main Claude. No swarm.

LOAD

1. Read SPEC.md. If missing → tell user to invoke the spec skill first. Stop.
2. Parse invocation args:

• §T.n → that task only
• --next or empty → lowest-numbered row with status .
• --all → every . row in §T order

PLAN

Native plan mode. For chosen task(s):

1. Cite every §V invariant that applies. Plan must respect all.
2. Cite every §I interface touched. Plan must preserve shape.
3. List files to create / edit.
4. List tests to add or update (one per invariant touched).
5. Name verification command (test, build, lint).

Emit plan inline every task — transparency, not wait-state — then proceed to EXECUTE.

EXECUTE

Per task in order (status flips . → x direct):

1. Edit code per plan.
2. Run verification command.

2'. On staged diff touching PUBLISHED, probe .claude/check-extras.md and run audit recipes it ships; bail per recipe message every surviving match, not commit until match-free. Probe not match → no-op.

1. Pass (verification exits 0 and tests added per plan and not §V regressed via full-suite re-run) → flip §T.n status . → x; auto-commit. Surface /sdd:check as Next-block item #1 per §V.<n> (cascade scan; not silent close). Next task.
2. Fail → invoke backprop skill. Do NOT retry blindly. Status stays ..

FAIL → BACKPROP

On test/build failure:

1. Read failure output.
2. Classify failure: (a) code bug → step 3, (b) spec wrong → step 4, (c) unspec edge → step 4. Confident → proceed direct. Low-confidence (ambiguous or multiple plausible) → AskUserQuestion per decision-gate invariant w/ 3 options keyed (a)/(b)/(c), labels is action descriptions ("Code bug — fix and re-run", "Spec wrong — /sdd:spec bug:", "Unspec edge — /sdd:spec bug:"), header Verify-fail class.
3. (a) → fix code, re-run. No spec change.
4. (b) or (c) → invoke spec skill with bug: <cause> first, let it update §V and §B, then resume build against updated spec.

Rule: never silently fix root-cause without considering backprop. §B records bug-class precedent so recurrence-class blocked.

WRITE POLICY

• Only flip §T status. No other SPEC.md edits from build.
• Other spec edits → invoke spec skill.
• Auto-commit on . → x per §T row; not user prompt. Message: T<n>: <goal line> + §V cites.
• Stage explicit git add <listed-paths> per plan; not git add -A — pre-existing dirty working-tree state not bundled.
• /sdd:build --all chains plan-once → every §T row {edit → verify → commit} autonomously.
• FAIL → not commit; FAIL→BACKPROP runs first.

OUTPUT — "Next" block

Heading ## Next; 1–5 atomic items (one sentence each, no Reply prefix); positional dispatch (run <int> or run /<plugin>:<cmd> [args]). Optional ## Hint (≤ 3 lines) precedes when item selection needs hidden state. PLAN not wait-state so not execute/revise/abort items; EXECUTE-pass auto-commits so Next leads w/ /sdd:check post-§T-close cascade; after backlog cleared, swap /sdd:build --next for /sdd:spec seed.

Canonical example after EXECUTE pass (commit already auto-fired):

## Next

1. /sdd:check — cascade scan over the just-closed §T row
2. /sdd:build --next — start the next pending §T row
3. /sdd:spec amend §T.<n> — re-scope before continuing

Variant: backlog cleared (terminal state) → swap item 2 for /sdd:spec (seed new row), drop item 3.

NON-GOALS

• No progress dashboards. cat SPEC.md | grep §T is the dashboard.
• No speculative work beyond chosen task scope.