PRD-per-sprint evolution route for an existing harness-built (or brownfield) system — grounds a new PRD against the prior requirement spine, produces a human-approved design amendment against the living specs/design/ baseline, then runs /auto. Companion to /build (sprint 1) and /feature (single-story changes).
PRD-per-sprint evolution route for an existing harness-built (or brownfield) system — grounds a new PRD against the prior requirement spine, produces a human-approved design amendment against the living specs/design/ baseline, then runs /auto. Companion to /build (sprint 1) and /feature (single-story changes).
argument-hint
<prd-file> [--autonomous]
Sprint Skill — PRD-per-Sprint Evolution
/sprint is a thin conductor, like /feature, for evolving a system PRD
by PRD without regenerating its architecture from scratch each time. It
grounds the new PRD against the prior sprint's requirement spine, amends the
living specs/design/ baseline instead of replacing it, and gates code
generation on a human-reviewable diff of the design amendment — never a
regenerated document. See
docs/superpowers/specs/2026-07-04-sprint-delta-lane-design.md for the full
design rationale.
Use /build for sprint 1 (no existing code or specs). Use /feature for a
single story or small cluster that doesn't need a full PRD. /sprint is for
"here is the next PRD" — many stories, evolving an existing architecture.
Runs in the main session — do not add context: fork. Like /feature,
this conductor owns interactive human gates (GATE 1, GATE 2) and delegates the
actual work to forked sub-skills.
There is no --auto (zero-gate) mode — GATE 2 (design-delta approval) is
never collapsible, by design.
Wrong-door protection
Before anything else, check specs/design/architecture.md:
If it does not exist and the repo has no source code (a fresh, empty
project) — this is sprint 1, not sprint N. Stop and tell the human to run
/build <prd> instead.
If it does not exist but source code exists (a true brownfield app the
harness did not build) — proceed to Phase 0's baseline recovery.
If it exists — proceed normally.
/build's own Step 0 carries the mirror check: if specs/design/architecture.md
already exists when /build is invoked, /build stops and redirects here.
Phase 0 — Preflight & Baseline (fully automatic, no flags)
Baseline recovery. If specs/design/architecture.md is missing (true
brownfield): run /design --baseline-recovery (see design/SKILL.md's
Baseline Recovery Mode). This runs /brownfield discovery first if
specs/brownfield/code-graph.json does not exist, then derives a living
design set from the graph, stamped provenance: derived-from-code, with
a one-time human approval before proceeding. After this, treat the repo
as if it already had an approved baseline.
DeepWiki freshness. If specs/brownfield/wiki/ exists, check for a
> STALE since… banner; if present, patch it incrementally via
/code-map --files on the flagged files, the same mechanism /feature
already uses.
Sprint number. List specs/brd/sprint-*/ directories; the sprint
number for this run is one greater than the highest found, or 2 if only
the flat legacy specs/brd/brd.md exists (sprint 1 was built before
sprint-numbered directories existed). State the resolved sprint number
before proceeding.
Phase 1 — Requirements Delta
Run /brd --delta <prd-file> (see brd/SKILL.md's Delta Mode). This writes
specs/brd/sprint-N/ and, critically,
specs/brd/sprint-N/requirements-delta.json classifying every requirement as
new/changed/carried against the prior sprint's spine. Any unresolved
dropped entry halts here per that skill's Step Δ2 — do not proceed with a
silent requirement regression.
Phase 2 — Story Decomposition
Run /spec specs/brd/sprint-N/brd.md --sprint N (see spec/SKILL.md's
sprint addendum). Writes specs/stories/sprint-N/.
Reuse-or-justify — REQUIRED SUB-SKILL: reuse-or-justify when the PRD
adds or materially extends behavior. Invoke reuse-or-justify at intake with the
sprint's theme as the goal string and the sprint's story directory
specs/stories/sprint-N/ as its batch, so intra-batch clusters across the
sprint's stories surface, before GATE 1. The sub-skill grounds on reuse-scout
itself: on a fire it settles reuse-vs-new (and any touched invariant / budget);
otherwise it records the net-new assumption and proceeds. The decision is
recorded either way — do not run reuse-scout here yourself.
The requirements-delta classification (new / changed / carried / dropped,
with resolution for each dropped item)
The story decomposition summary (epic table, dependency graph, story-point
total) from /spec's own Step 7 output
Ask: "Does this requirement delta and story decomposition look correct?
Approve to proceed to the design amendment, or provide corrections."
With --autonomous, skip this as a separate stop — fold its summary into the
single GATE 2 presentation instead (do not skip the underlying /brd --delta
and /spec grounding gates themselves, only the human stop).
Phase 3 — Design Delta
Run /design --delta --stories specs/stories/sprint-N/ --amendment-id sprint-N
(see design/SKILL.md's Delta Mode, Steps D1–D6): read the living baseline,
spawn one planner agent to write the amendment and amend the living design
non-destructively, emit the grounding gate, run the contract-drift check, and
run the design-delta evaluator rubric.
This is design/SKILL.md Delta Mode's Step D7, run from here. Never skipped,
never folded away in any autonomy mode. On approval, the amendment and
updated living-design files are committed together in one commit.
Phase 4 — Tracker Publish (optional)
If a tracker is configured (.claude/tracker-config.json), run
tracker-publish --granularity group exactly as /feature's epic lane does.
Phase 5 — Delta Test Plan
Run /test (the normal flow, not --from-cr — that lane is for a single
change-request bug fix with no stories directory) scoped to
specs/stories/sprint-N/, so every new story gets a proper test plan and
grounded verification-matrix entries exactly as a fresh spec/design pass
would produce. Any existing area the amendment's Breaking Changes section
names is covered by that area's own existing tests, which /auto's normal
test gate re-runs — no separate regression-pin pass is needed since sprint-N
stories already carry proper story-traces.json.
Phase 6 — Build
Run /auto. The merged specs/design/component-map.md (already updated by
Phase 3) means the existing ownership, canvas-sync, layer, and context
sensors now enforce the evolved design automatically — no /auto changes
needed.
Phase 7 — Gate and PR
Run /gate, then open the PR(s) exactly as /build//feature do. Merge
stays human.
State markers
At the start of Phase 0, write .claude/state/current-sprint (the resolved
sprint number, e.g. 2) and update .claude/state/sprint-phase at the start
of every phase (preflight, requirements-delta, story-decomposition,
design-delta, tracker-publish, test-plan, build, gate) so /status
can show sprint progress:
Never let Phase 3 regenerate specs/design/ from scratch. If the
planner agent's output looks like a fresh design rather than an amendment
(missing prior component-map rows, a rewritten architecture.md with no
trace to the prior version), stop and re-invoke Delta Mode Step D3 with a
stronger instruction to read the baseline first.
GATE 2 here is not /feature's GATE 2. They serve different lanes
(PRD-scale vs single-story) but share the same underlying
design/SKILL.md Delta Mode machinery — do not conflate the two
conductors.
Do not skip the requirements-delta dropped-item resolution. An
unresolved dropped entry is exactly the silent regression this lane
exists to prevent.
--autonomous folds human stops, never machine gates. The grounding
gates, contract-drift check, and design-delta evaluator all still run.
